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UNIT 2—THE BIG BANG
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CHANGING VIEWS .............................................................................................................. 2
PTOLEMY ......................................................................................................................... 2
GALILEO ........................................................................................................................... 8
COPERNICUS ................................................................................................................ 21
NEWTON ........................................................................................................................ 31
HUBBLE .......................................................................................................................... 38
APPROACHES TO KNOWLEDGE .................................................................................... 46
STRUCTURE OF SCIENTIFIC REVOLUTIONS ................................................................. 55
HENRIETTA LEAVITT ........................................................................................................ 66
TYCHO BRAHE .................................................................................................................. 73
SCIENCE, THEOLOGY, & COPERNICAN REVOLUTION ................................................. 77
THE VATICAN OBSERVATORY........................................................................................ 87
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UNIT 2 —THE BIG BANG TEXT READER
1
Changing Views
This is a collection of articles that details the changing view of the Universe from geocentric
to heliocentric. There is an article on each of these scientists: Ptolemy, Galileo, Copernicus,
Newton, and Hubble.
Ptolemy
He studied the stars with his naked eye, and put us at the center of the Universe.
Claudius Ptolemy: An Earth-Centered View of the Universe (1260L)
By Cynthia Stokes Brown
The Earth was the center of the Universe, according to Claudius Ptolemy, whose view of the
cosmos persisted for 1,400 years until it was overturned — with controversy — by findings
from Nicolaus Copernicus, Galileo Galilei, and Isaac Newton.
An astronomer in ancient times
Claudius Ptolemy lived in Alexandria, Egypt, from about 85 to 165 CE. The city was
established by Alexander the Great about 400 years before Ptolemy’s birth. Under its Greek
rulers, Alexandria cultivated a famous library that attracted many scholars from Greece, and
its school for astronomers received generous patronage. After the Romans conquered Egypt
in 30 BCE, Alexandria became the second-largest city in the Roman Empire and a major
source of Rome’s grain, but less funding was provided for scientific study of the stars.
Ptolemy was the only great astronomer of Roman Alexandria.
Ptolemy was also a mathematician, geographer, and astrologer. Befitting his diverse
intellectual pursuits, he had a motley cultural makeup: he lived in Egypt, wrote in Greek, and
bore a Roman first name, Claudius, indicating he was a Roman citizen — probably a gift
from the Roman emperor to one of Ptolemy’s ancestors.
A geocentric view
Ptolemy synthesized Greek knowledge of the known Universe. His work enabled
astronomers to make accurate predictions of planetary positions and solar and lunar
eclipses, promoting acceptance of his view of the cosmos in the Byzantine and Islamic
worlds and throughout Europe for more than 1,400 years.
Ptolemy accepted Aristotle’s idea that the Sun and the planets revolve around a spherical
Earth, a geocentric view. Ptolemy developed this idea through observation and in
mathematical detail. In doing so, he rejected the hypothesis of Aristarchus of Samos, who
came to Alexandria about 350 years before Ptolemy was born. Aristarchus had made the
UNIT 2 —THE BIG BANG TEXT READER
2
claim that the Earth revolves around the Sun, but he couldn’t produce any evidence to back
it up.
Based on observations he made with his naked eye, Ptolemy saw the Universe as a set of
nested, transparent spheres, with Earth in the center. He posited that the Moon, Mercury,
Venus, and the Sun all revolved around Earth. Beyond the Sun, he thought, sat Mars,
Jupiter, and Saturn, the only other planets known at the time because they were visible to
the naked eye. Beyond Saturn lay a final sphere — with all the stars fixed to it — that
revolved around the other spheres.
This idea of the Universe did not fit exactly with all of Ptolemy’s observations. He was aware
that the size, motion, and brightness of the planets varied. So he incorporated Hipparchus’s
notion of epicycles, put forth a few centuries earlier, to work out his calculations. Epicycles
were small circular orbits around imaginary centers on which the planets were said to move
while making a revolution around the Earth. By using Ptolemy’s tables, astronomers could
accurately predict eclipses and the positions of planets. Because real visible events in the
sky seemed to confirm the truth of Ptolemy’s views, his ideas were accepted for centuries
until the Polish astronomer, Copernicus, proposed in 1543 that the Sun, rather than the
Earth, belonged in the center.
After the Roman Empire dissolved, Muslim Arabs conquered Egypt in 641 CE. Muslim
scholars mostly accepted Ptolemy’s astronomy. They referred to him as Batlaymus and
called his book on astronomy al-Magisti, or “The Greatest.” Islamic astronomers corrected
some of Ptolemy’s errors and made other advances, but they did not make the leap to a
heliocentric (Sun-centered) universe.
Ptolemy’s book was translated into Latin in the 12th century and was known as The
Almagest, from the Arabic name. This enabled his teachings to be spread throughout
Western Europe.
We know few details of Ptolemy’s life. But he left one personal poem, inserted right after the
table of contents in The Almagest:
Well do I know that I am mortal, a creature of one day.
But if my mind follows the wandering path of stars
Then my feet no longer rest on earth, but standing by
Zeus himself, I take my fill of ambrosia, the food of the gods.
Claudius Ptolemy: An Earth-Centered View of the Universe (1090L)
By Cynthia Stokes Brown, adapted by Newsela
Ptolemy's view of the earth-centered view of the cosmos persisted for 1,400 years. Only until
findings from Nicolaus Copernicus, Galileo Galilei, and Isaac Newton was it overturned.
UNIT 2 —THE BIG BANG TEXT READER
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An astronomer in ancient times
Claudius Ptolemy lived in Alexandria, Egypt, from about 85 to 165 CE. The city was founded
by Alexander the Great. Under its Greek rulers, Alexandria developed a famous library that
attracted many scholars from Greece, and its school for astronomers received generous
funding. After the Romans conquered Egypt in 30 BCE, Alexandria became the secondlargest city in the Roman Empire, but less money was provided for astronomy. Ptolemy was
the only great astronomer of Roman Alexandria.
Ptolemy was also a mathematician, geographer, and astrologer. Along with many intellectual
interests, he had many different cultural influences in his life. He lived in Egypt, wrote in
Greek, and had a Roman first name, Claudius, which showed he was a Roman citizen.
A geocentric view
Ptolemy collected and summarized Greek knowledge of the known Universe. His work
enabled astronomers to pinpoint the planets and predict solar and lunar eclipses. Because
of this, his ideas were accepted by Byzantine, Islamic and Europe scholars for more than
1,400 years.
Ptolemy accepted Aristotle’s idea that the Sun and the planets revolve around a spherical
Earth, a geocentric view. Ptolemy developed this idea through observation and in
mathematical detail. In doing so, he rejected the hypothesis of Aristarchus of Samos, who
came to Alexandria about 350 years before Ptolemy was born. Aristarchus had made the
claim that the Earth revolves around the Sun, but he couldn’t produce any evidence to back
it up.
Based on observations he made with his naked eye, Ptolemy saw the Universe as a set of
nested, transparent spheres, with Earth in the center. He posited that the Moon, Mercury,
Venus, and the Sun all revolved around Earth. Beyond the Sun, he thought, sat Mars,
Jupiter, and Saturn, the only other planets known at the time because they were visible to
the naked eye. Beyond Saturn lay a final sphere — with all the stars fixed to it — that
revolved around the other spheres.
This idea of the Universe did not fit exactly with all of Ptolemy’s observations. He was aware
that the size, motion, and brightness of the planets varied. So he incorporated Hipparchus’s
notion of epicycles to work out his calculations. Epicycles were small circular orbits around
imaginary centers on which the planets were said to move while making a revolution around
the Earth. By using Ptolemy’s tables, astronomers could accurately predict eclipses and the
positions of planets. Because real visible events in the sky seemed to confirm the truth of
Ptolemy’s views, his ideas were accepted for centuries. They only came into doubt when the
Polish astronomer, Copernicus, proposed in 1543 that the Sun belonged in the center – not
the earth.
After the Roman Empire dissolved, Muslim Arabs conquered Egypt in 641 CE. Muslim
scholars mostly accepted Ptolemy’s astronomy. They referred to him as Batlaymus and
called his book on astronomy al-Magisti, or “The Greatest.” Islamic astronomers corrected
UNIT 2 —THE BIG BANG TEXT READER
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some of Ptolemy’s errors and made other advances, but they did not make the leap to a
heliocentric (Sun-centered) universe.
Ptolemy’s book was translated into Latin in the 12th century and was known as The
Almagest, from the Arabic name. This enabled his teachings to be spread throughout
Western Europe.
We know few details of Ptolemy’s life. But he left one personal poem, inserted right after the
table of contents in The Almagest:
Well do I know that I am mortal, a creature of one day.
But if my mind follows the wandering path of stars
Then my feet no longer rest on earth, but standing by
Zeus himself, I take my fill of ambrosia, the food of the gods.
Claudius Ptolemy: An Earth-Centered View of the Universe (890L)
By Cynthia Stokes Brown, adapted by Newsela
The Earth was the center of the Universe, according to Claudius Ptolemy. His view of the
cosmos was accepted for 1,400 years. Later, Nicolaus Copernicus, Galileo Galilei, and Isaac
Newton contradicted Ptolemy’s ideas.
An astronomer in ancient times
Claudius Ptolemy lived in Alexandria, Egypt from about 85 to 165 CE. Alexandria was
established by Alexander the Great about 400 years before Ptolemy’s birth.
Under its Greek rulers, Alexandria had a famous library that attracted many scholars from
Greece. Its school for astronomers received generous support.
After the Romans conquered Egypt in 30 BCE, there was less funding provided for scientific
study of the stars. Ptolemy was the only great astronomer of Roman Alexandria.
Ptolemy was also a mathematician, geographer, and astrologer. Along with many intellectual
interests, he had many cultural influences. He lived in Egypt, wrote in Greek, and had a
Roman first name, Claudius, which showed he was a Roman citizen.
A geocentric view
Ptolemy collected and summarized Greek knowledge of the known Universe. His work
allowed astronomers to predict eclipses of the sun and moon, and the positions of planets.
His view of the cosmos was accepted for more than 1,400 years in the Byzantine and
Islamic worlds and throughout Europe.
Ptolemy accepted Aristotle’s idea that the Sun and the planets revolve around a spherical
Earth. This is called a geocentric view. Ptolemy developed this idea by observing the sky
and using mathematics.
UNIT 2 —THE BIG BANG TEXT READER
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Aristarchus of Samos lived in Alexandria about 350 years before Ptolemy. Aristarchus
claimed that the Earth revolves around the Sun. He couldn’t produce any evidence to
support his view, and Ptolemy rejected it.
Ptolemy made observations of the stars and planets with his naked eye. He imagined a
Universe with Earth in the center. Around Earth was a set of transparent spheres. He
thought that the Moon, Mercury, Venus, and the Sun all revolved around Earth. Past the Sun
were Mars, Jupiter, and Saturn. Past Saturn was a final sphere that had all the stars
attached to it. This final sphere revolved around the other ones.
This idea of the Universe did not fit exactly with all of Ptolemy’s observations. He knew that
the size, motion, and brightness of the planets changed. Ptolemy solved this problem by
borrowing a centuries-old idea from Hipparchus. The idea was epicycles: mini-orbits that the
planets made while revolving around the Earth.
Astronomers could accurately predict eclipses and the positions of planets by using
Ptolemy’s tables. His ideas were accepted for centuries because real visible events in the
sky seemed to confirm his views. But in 1543, the Polish astronomer Copernicus proposed
that the Sun, not the Earth, belonged in the center.
After the Roman Empire dissolved, Muslim Arabs conquered Egypt in 641 CE. Muslim
scholars mostly accepted Ptolemy’s astronomy. They referred to him as Batlaymus and
called his book on astronomy al-Magisti, or “The Greatest.” Islamic astronomers corrected
some of Ptolemy’s errors and made other advances, but they did not consider a heliocentric
(Sun-centered) universe.
Ptolemy’s book was translated into Latin in the 12th century. It was known as The Almagest,
from the Arabic name. This allowed his teachings to be spread throughout Western Europe.
We know few details of Ptolemy’s life. But he left one personal poem, inserted right after the
table of contents in The Almagest:
Well do I know that I am mortal, a creature of one day.
But if my mind follows the wandering path of stars
Then my feet no longer rest on earth, but standing by
Zeus himself, I take my fill of ambrosia, the food of the gods.
Claudius Ptolemy: An Earth-Centered View of the Universe (780L)
By Cynthia Stokes Brown, adapted by Newsela
Claudius Ptolemy was an ancient astronomer who studied the skies with his naked eye. He
believed the Earth was at the center of the Universe. This view was accepted for 1,400
years until Nicolaus Copernicus, Galileo Galilei, and Isaac Newton came along.
UNIT 2 —THE BIG BANG TEXT READER
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Ancient astronomer in Alexandria
Ptolemy lived in Alexandria, Egypt. The famous ancient city was founded by Alexander the
Great.
At the time, Alexandria was a great center of learning. There was a famous library where
many Greek scholars studied. There was a school for astronomers. Wealthy families gave
money to the library and schools.
But then the Romans conquered Egypt in 30 BCE. There was less money for studying the
stars. Ptolemy was the only great astronomer from Alexandria during this time.
Claudius Ptolemy wasn’t only interested in stars and planets. He also studied maps, math,
and astrology. He lived in Egypt, wrote in Greek, and had a Roman first name.
Earth at the center of the universe?
Ptolemy studied the Greek knowledge of the known Universe. Aristotle said that the Sun and
the planets all revolve around Earth. This geocentric view sees Earth as the center of the
Universe. (geo - Earth, centric - centered).
Ptolemy agreed with Aristotle.
Of course, the Earth is not the center of the Universe, as we now know. But amazingly,
Ptolemy’s system worked. He could accurately predict the positions of planets. He could
also accurately predict when the Sun and Moon would be eclipsed.
Ptolemy studied the sky with his naked eye — no telescope. He used math to track the
planets and stars.
He saw a Universe with Earth in the center. Around Earth were huge transparent spheres.
He thought that the Moon, Mercury, Venus, and the Sun all revolved around Earth. Past the
Sun were Mars, Jupiter, and Saturn. Past Saturn was a final sphere that had all the stars
attached to it. This final sphere revolved around the other spheres.
Because his system worked, it was believed all over the world. For more than 1,400 years
people accepted Ptolemy’s spheres.
In 1543, though, Polish astronomer Copernicus correctly claimed that the Sun is at the
center of our Universe, not the Earth.
His work lives on
The Roman Empire dissolved, and Muslim Arabs conquered Egypt in 641 CE. Muslim
scholars mostly accepted Ptolemy’s astronomy. They corrected some of his errors, and
made some advances, but they did not consider a heliocentric (Sun-centered) Universe.
Ptolemy’s book was translated into Latin in the 12th century. This allowed his teachings to
be spread throughout Western Europe.
We know few details of Ptolemy’s life. But he left one personal poem, inserted right after the
table of contents in his book:
UNIT 2 —THE BIG BANG TEXT READER
7
Well do I know that I am mortal, a creature of one day.
But if my mind follows the wandering path of stars
Then my feet no longer rest on earth, but standing by
Zeus himself, I take my fill of ambrosia, the food of the gods.
Galileo
An Italian Renaissance man, Galileo used a telescope of his own invention to collect
evidence that supported a Sun-centered model of the Solar System.
Galileo Galilei: The Father of Modern Observational Astronomy
(1220L)
By Cynthia Stokes Brown
Galileo Galilei, an Italian Renaissance man, used a telescope of his own invention to collect
evidence that supported a Sun-centered model of the Solar System.
Youth and education
Galileo Galilei was born in Pisa, Italy, on February 15, 1564, the first of seven children of
Vincenzo Galilei and Giulia Ammanati. Galileo’s father was a musician — a lute player —
from a noble background.
When Galileo was 10, his family moved to Florence, northeast of Rome, where he was
educated in a monastery. He was attracted to the priesthood, but his father steered him to
study medicine from 1581 to 1585 at the University of Pisa, 40 miles west of Florence on the
coast, and very near Galileo’s childhood home.
University studies at that time were based primarily on Aristotle’s philosophy, but Galileo’s
acute observations caused him to question some of these accepted views. He noticed that
hailstones of different sizes reached the ground simultaneously, contradicting Aristotle’s rule
that bodies fall with speeds proportional to their size. At this time, Galileo also sat in on
lectures by a practical mathematician, apart from his university studies.
Professor at Pisa and Padua
After four years at university, Galileo gave private lessons in mathematics and wrote his first
scientific paper, about how things float on water. In 1587, he got a position teaching
mathematics at the University of Pisa, which paid him a very modest salary. Two years later,
Galileo’s father died, leaving Galileo responsible for the promised dowries of his two sisters.
The next year he secured the chair of mathematics at the renowned University of Padua,
and the new position paid three times as much. In addition to mathematics, Galileo gave
private instruction in military architecture, fortification, surveying, and mechanics.
UNIT 2 —THE BIG BANG TEXT READER
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At the age of 31, Galileo showed his first interest in astronomy, while working to explain the
cause of the tides. Padua was 20 miles inland from Venice, an important trading port on the
Adriatic Sea. Astronomy was considered part of mathematics at the time, while cosmology
was part of philosophy. Most scholars still held the views of Ptolemy, who followed Aristotle
in thinking that all heavenly bodies revolve around Earth (a geocentric model). But other
views were being considered, including that of Nicolaus Copernicus, who claimed that all
bodies revolve around the Sun (a heliocentric model), and of Danish astronomer Tycho
Brahe, who held that Earth was fixed but other planets are in orbit around the Sun.
In 1597, Galileo read a book by German astronomer Johannes Kepler, who was
enthusiastically pro-Copernicus. Galileo wrote a letter to Kepler stating that he had long
agreed with Copernicus, but that he had not dared to make his thoughts public because he
was frightened that he would become, like Copernicus, “mocked and hooted by an infinite
multitude.” In the same year, Galileo invented a mechanical device for mathematical
calculations. He had a craftsman make them, so that Galileo could sell them and give
classes on how to use them.
Professors at Padua tended not to marry, and prominent families there did not view Galileo
as a catch. Instead, Galileo established a lasting relationship with a non-noble woman 14
years younger, Marina Gamba, and had three children with her. He never married her, and
she and the children lived separately, around the corner from him. When he later left Padua
in 1610 to move to Florence, he put their two daughters in a convent as soon as possible,
and he left his son, Vincenzo, in Padua in Marina’s care.
Galileo’s first known astronomical observation occurred in 1604, when a supernova (the
explosive death of a high-mass star) was visible in the sky. Such an event clearly challenged
Aristotle’s claim that no change could ever take place in the heavens. From then on,
observation and experimentation became the basis for Galileo’s work. Galileo’s prominence
as a mathematician and scholar grew, and in the summer of 1605 he arranged to tutor
Cosimo de Medici, the son of the Grand Duke of Tuscany.
In July 1609, Galileo heard about a Dutch device for making distant objects look nearer. A
friend who saw it described it to Galileo as having two lenses, one on each end of a 4-foot
tube. Within about a month, Galileo had made an instrument three times as powerful as the
Dutch device.
Galileo continued to work on his telescope, grinding his own lenses. By December 1609, he
had seen for the first time the four largest moons orbiting around Jupiter, which contradicted
Ptolemaic theory that Earth is the center of all orbiting bodies. Galileo published his findings
in March 1610 as The Starry Messenger. The general public was excited, but most
philosophers and astronomers declared it an optical illusion.
Mathematics at the court of Tuscany
Galileo was offered life tenure at the University of Padua, but Florence was his home, and
he wanted freedom from teaching. So he took the job of court mathematician in Florence,
where his former math student had become Cosimo II, the Grand Duke of Tuscany.
UNIT 2 —THE BIG BANG TEXT READER
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Soon after his arrival in Florence in September 1610, Galileo began his observations of
Venus. Over time he discovered that the Moon-like phases of Venus demonstrated that the
neighboring planet had an orbit independent of Earth. This showed conclusively that Venus
circled the Sun, as Copernicus thought, not Earth, as Ptolemy thought. But it did not yet
prove conclusively that Earth circled the Sun.
In 1613, Galileo published his Letters on Sunspots, based on his observations of the dark
spots on the Sun that are caused by intense magnetic activity.
In an appendix, he noted that he agreed with Copernicus, mentioning the fact that he had
seen eclipses of the satellites of Jupiter, further evidence that they orbited the planet. This is
the only time that Galileo expressed in print his support of the Copernican model. Galileo
had no definitive evidence that Copernicus was right, and he didn’t claim that he did.
Galileo’s main pieces of evidence were the phases of Venus; the eclipses of Jupiter’s
moons; the existence of tides, which Galileo believed could only occur if the Earth moved;
observable planetary speeds, and the distances of planets from the Sun.
Drama with the Inquisition
During the first part of the 16th century, the Catholic Church was facing the challenge of
Protestants, who were breaking away from the Church over certain doctrines. By this time,
there were printers in many European cities and ideas were spreading quickly, some of them
in opposition to the Catholic Church and its beliefs. To combat all heresies, the Pope set up
a system of tribunals, or courts, called the Inquisition.
In 1616, the year of Shakespeare’s death, the authorities of the Inquisition in Rome decided
to prohibit Copernicus’s book, On the Revolutions of the Celestial Spheres, and any other
books that argued in favor of a Copernican Sun-centered model for the Solar System.
Galileo traveled to Rome to try to prevent this; he thought it was a mistake that would
eventually tarnish the Church’s reputation. He believed that the Catholic Church should keep
science and religion completely separate and not interfere with scientific research. The
Church upheld its position, and Galileo agreed to obey the ban.
In 1623, a Florentine who admired Galileo became Pope Urban VIII. Galileo had six
audiences (meetings) with the Pope in 1624 and received permission to publish his theory
on the causes of tides, provided he did not take sides on the cosmological debate. For the
next six years, Galileo worked on this book, which turned into a dialogue concerning the
relative merits of the Ptolemaic and the Copernican conceptions of the Universe, without
reaching a conclusion of one over the other. To carry out the discussion, Galileo invented
three characters: Salviati, who gave Copernicus’s views; Simplicio, who presented
Aristotelian/Ptolemaic views; and Sagredo, an interested layman. Simplicio was named for
an ancient Greek commentator on Aristotle. The title in English was Dialogue Concerning
the Two Chief World Systems – Ptolemaic and Copernican.
The publisher of the book received a license to print, and the book appeared in Florence in
March 1632. An outbreak of the plague delayed copies being sent to Rome. In August of the
same year, an order came from the Roman Inquisition to stop all sales.
UNIT 2 —THE BIG BANG TEXT READER
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Galileo’s student and friend, the Grand Duke Cosimo II, had died in 1621. The new Grand
Duke of Tuscany, Ferdinand, protested the book, which seemed to him, and to many of the
Church leaders, to portray Simplicio as a simpleton and fool, and thus to take sides in the
debate. The Pope considered the character of Simplicio an insult, as did the other Church
leaders. In September 1632, Galileo was charged with “vehement suspicion of heresy” and
ordered to come to Rome for a trial. Ill, he did not appear until February 1633.
Galileo denied that he was defending heliocentrism, but he finally admitted that one could
get that impression from the book. He was threatened with torture, forced to recant the
heliocentric model, and, in June of that year, sentenced to indefinite imprisonment in Rome.
His book was put on the Index of Prohibited Books. Three of the 10 judges disagreed with
the verdict. Legend has it that as Galileo left the courtroom he whispered, “Eppur si muove
[Still it (Earth) moves],” but this was most likely invented later.
Galileo was crushed by the harsh verdict. The archbishop of Siena, who had disagreed with
the verdict, got permission to take Galileo into his home and helped him through his
depression. Two years before his trial, Galileo had taken a villa on the outskirts of Florence,
to be next to the convent where his daughters were nuns. After a few months in Rome,
Galileo received permission to return to his own villa, to be guarded by representatives of
the Inquisition, a house arrest. He was ill with a hernia, heart palpitations, and insomnia. A
few months after his return home, his older daughter, Maria Celeste, with whom he was very
close, died in April 1634.
The following year Galileo’s book, Dialogue Concerning the Two Chief World Systems –
Ptolemaic and Copernican, was published in Latin in Strasburg, Alsace (France), outside the
grasp of the Catholic Inquisition, thereby reaching a much more cosmopolitan audience than
the suppressed Italian text.
Blindness and a legacy of truth
Galileo rallied and in his last years wrote a book summarizing all his ideas, published in
1637 in Holland in Italian. This book was translated into English in 1661 as Discourses and
Mathematical Demonstrations Relating to Two New Sciences, and Isaac Newton read it in
1666.
By 1638, Galileo had become totally blind. He was allowed to live with his son in Florence
and have visitors as long as they were not mathematicians. He carried on a great deal of
correspondences by dictating his letters to others. He died on January 9, 1642, in Florence,
at the age of 77. He was not allowed to be buried in the main body of the Basilica of Santa
Croce, but in a small room at the end of a corridor; he was reburied in the main part in 1737.
The Catholic Church took 200 years to remove Galileo’s book from the Index of Prohibited
Books, finally doing so in 1835. In 1992, Pope John Paul II expressed regret at how the
Church had handled Galileo and issued a declaration acknowledging the errors committed
by the court of the Catholic Church. In 2008, plans were announced for a statue of Galileo
inside the Vatican walls, but in 2009 these plans were suspended.
Galileo’s own words to a friend about his blindness serve as a suitable epitaph:
UNIT 2 —THE BIG BANG TEXT READER
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Alas, your friend and servant Galileo has for the last month been irremediably blind, so that
this heaven, this Earth, this Universe which I, by my remarkable discoveries and clear
demonstrations had enlarged a hundred times beyond what had been believed by wise men
of past ages, for me is from this time forth shrunk into so small a space as to be filled by my
own sensations. (Drake, p. 107)
Galileo Galilei: The Father of Modern Observational Astronomy
(1030L)
By Cynthia Stokes Brown, adapted by Newsela
Galileo Galilei, an Italian scholar, invented a telescope to collect evidence that supported a
Sun-centered model of the Solar System.
Youth and education
Galileo Galilei was born in Pisa, Italy, on February 15, 1564. He was the first of seven
children. Galileo’s father was a musician — a lute player — from a noble background.
When Galileo was 10, his family moved to Florence, northeast of Rome, where he was
educated in a monastery. He wanted to become a priest, but his father pushed him to study
medicine at the University of Pisa.
University studies at that time were based primarily on Aristotle’s philosophy, but Galileo’s
sharp observations caused him to question some of these accepted views.
For example, he noticed that hailstones of different sizes reached the ground
simultaneously, contradicting Aristotle’s rule that objects of different sizes fall at different
speeds.
At this time, Galileo also sat in on lectures by a practical mathematician.
Professor at Pisa and Padua
After four years at the university, Galileo gave private lessons in mathematics and wrote his
first scientific paper, about how things float on water. In 1587, he got a position teaching
mathematics at the University of Pisa, which paid him a small salary.
Two years later, Galileo’s father died, leaving Galileo with financial responsibilities. The next
year he became the chair of mathematics at the famous University of Padua. The new
position paid three times as much. In addition to mathematics, Galileo gave private
instruction in military architecture, fortification, surveying, and mechanics.
At the age of 31, Galileo showed his first interest in astronomy, while studying tides. Padua
is near Venice, an important trading port on the Adriatic Sea.
Astronomy was considered part of mathematics at the time, while cosmology, which is the
study of the origins of the Universe, was part of philosophy.
UNIT 2 —THE BIG BANG TEXT READER
12
Most scholars still agreed with Ptolemy and Aristotle that all heavenly bodies revolve around
Earth (a geocentric model).
But other views were being considered. Nicolaus Copernicus claimed that all bodies revolve
around the Sun (a heliocentric model). Danish astronomer Tycho Brahe believed that Earth
was fixed but other planets orbited around the Sun.
In 1597, a German visitor gave Galileo a book by German astronomer Johannes Kepler,
who was enthusiastically pro-Copernicus. Galileo wrote a letter to Kepler stating that he had
long agreed with Copernicus but that he hadn’t made his thoughts public because he was
frightened that he would become, like Copernicus, “mocked and hooted by an infinite
multitude.”
In the same year, Galileo invented a mechanical device for mathematical calculations.
Galileo had a craftsman make them, so that he could sell the devices and give classes on
how to use them.
Professors at Padua usually didn’t marry. Anyway, prominent families in Padua did not view
Galileo as a suitable husband.
Instead, Galileo established a long relationship with a non-noble woman 14 years younger
than him. He never married Marina Gama, but he had three children with her. She and the
children lived separately, around the corner from him.
When Galileo left Padua in 1610 to move to Florence, he put their two daughters in a
convent and left his son with Marina.
Galileo’s first known astronomical observation occurred in 1604, when a supernova was
visible in the sky. A supernova is the explosive death of a large star.
This event clearly challenged Aristotle’s claim that no change could ever take place in the
heavens. From then on, observation and experimentation became the basis for Galileo’s
work.
In July 1609, Galileo heard about a Dutch device for making distant objects look nearer —
an early telescope. A friend who saw it described it to Galileo as having two lenses, one on
each end of a 4-foot tube. Within about a month, Galileo had made a telescope three times
as powerful as the Dutch device. Galileo continued to work on his telescope, making his own
lenses.
Using the telescope, Galileo saw four moons orbiting Jupiter. This contradicted Ptolemy’s
idea that the Earth is the center of all orbiting bodies.
Galileo published his findings in March 1610 as The Starry Messenger. The general public
was excited, but most philosophers and astronomers declared it an optical illusion.
Mathematics at the court of Tuscany
Galileo was offered a lifetime job at the University of Padua, but Florence was his home, and
he wanted freedom from teaching. So he took the job of court mathematician in Florence.
UNIT 2 —THE BIG BANG TEXT READER
13
Soon after his arrival in Florence in September 1610, Galileo began his observations of
Venus. Over time, he discovered that the Moon-like phases of Venus demonstrated that the
neighboring planet had an orbit independent of Earth. This showed conclusively that Venus
circled the Sun, as Copernicus thought, not Earth, as Ptolemy thought. But it did not yet
prove conclusively that Earth circled the Sun.
In 1613, Galileo published his Letters on Sunspots, based on his observations of the dark
spots on the Sun that are caused by intense magnetic activity.
In an appendix, he noted that he agreed with Copernicus. Galileo had no definitive evidence
that Copernicus was right, and he didn’t claim that he did. Galileo’s main pieces of evidence
were the phases of Venus; the eclipses of Jupiter’s moons; the existence of tides, which
Galileo believed could only occur if the Earth moved; observable planetary speeds, and the
distances of planets from the Sun.
Drama with the Inquisition
In the early 1500s, the Catholic Church had a problem. Many people disagreed with the
Church on different issues. Protestants were breaking away to form their own Church.
Printers in many European cities helped ideas spread quickly. Some of these ideas went
against the Catholic Church.
To fight the spread of these ideas, the Pope set up a system of tribunals, or courts. It was
called the Inquisition.
In 1616 — the year of Shakespeare’s death — the Inquisition authorities in Rome decided to
ban Copernicus’s book, On the Revolutions of the Celestial Spheres. They banned the book
because it argued for a Sun-centered solar system.
They also banned any other books that agreed with Copernicus. This included Galileo’s
works.
Galileo traveled to Rome. He thought the Church was making a mistake that would hurt its
reputation. He believed the Catholic Church should keep science and religion completely
separate. The Church did not agree with Galileo. In the end, he agreed to obey the ban.
In 1623, Pope Urban VIII gave Galileo permission to publish his theory on the causes of
tides, as long as he did not take sides on the cosmological debate.
For the next six years, Galileo worked on this book. His book didn’t take one position on the
heliocentric versus geocentric debate. Instead, his book presented a discussion of the two
views. One character gave Copernicus’s view, another gave Aristototle/Ptolemy’s view, and
a third character was an interested regular person. The book was called Dialogue
Concerning the Two Chief World Systems – Ptolemaic and Copernican.
The book appeared in Florence in March 1632. An outbreak of the plague delayed copies
being sent to Rome. In August, an order came from the Roman Inquisition to stop all sales.
The Grand Duke of Tuscany, Ferdinand, protested the book. He felt the book actually
argued for a heliocentric model, even though it wasn’t supposed to take sides.
UNIT 2 —THE BIG BANG TEXT READER
14
In September 1632, Galileo was charged with “heresy” — disagreeing with the Church. He
was ordered to come to Rome for a trial. He did not appear until February 1633 because he
was ill.
Galileo denied that he was defending heliocentrism, but he finally admitted that one could
get that impression from the book. He was threatened with torture and forced to publicly give
up the Sun-centered model. His book was banned.
Legend has it that as Galileo left the courtroom he whispered, “Eppur si muove [Still it
(Earth) moves],” but this was most likely invented later.
Galileo was crushed by the harsh verdict. The Inquisition put him under house arrest at his
villa outside Florence. He was ill with a hernia, heart palpitations, and insomnia. A few
months after his return home, his older daughter, Maria Celeste, who he was very close to,
died.
The following year, Galileo’s book was published in Latin in France, outside the grasp of the
Catholic Inquisition, thereby reaching a much more sophisticated audience than the banned
Italian text.
Blindness and a legacy of truth
Galileo recovered from his serious setbacks. In 1637, he wrote a book summarizing all his
ideas. The book was translated into English, and Isaac Newton read it in 1666.
By 1638, Galileo had become totally blind. He wrote many letters by dictating them to others.
He died on January 9, 1642, in Florence, at the age of 77.
The Catholic Church didn’t lift the ban on Galileo’s book for 200 years — not until 1835. In
1992, Pope John Paul II expressed regret at how the Church treated Galileo.
Galileo’s own words to a friend about his blindness serve as a suitable epitaph:
Alas, your friend and servant Galileo has for the last month been irremediably blind, so that
this heaven, this Earth, this Universe which I, by my remarkable discoveries and clear
demonstrations had enlarged a hundred times beyond what had been believed by wise men
of past ages, for me is from this time forth shrunk into so small a space as to be filled by my
own sensations. (Drake, p. 107)
Galileo Galilei: The Father of Modern Observational Astronomy
(890L)
By Cynthia Stokes Brown, adapted by Newsela
Galileo Galilei was an Italian scholar who invented a telescope. With it, he collected
evidence of a Sun-centered Solar System.
UNIT 2 —THE BIG BANG TEXT READER
15
Youth and education
Galileo Galilei was born in Pisa, Italy, on February 15, 1564. He was the first of seven
children. Galileo’s father was a musician — a lute player — from a noble background.
Galileo wanted to become a priest, but his father pushed him to study medicine at the
University of Pisa.
University courses at this time were based on Aristotle’s teachings. But Galileo made sharp
observations and began to question some of Aristotle’s ideas.
For example, Aristotle had said that objects of different sizes fall at different speeds. Galileo
observed hailstones all hitting the ground at the same time. He decided that Aristotle was
wrong.
Is the Earth or the Sun at the center of it all?
Galileo became a professor of mathematics, first in Pisa, then in Padua. He also gave
private lessons in military architecture, fortification, surveying, and mechanics.
Galileo began studying tides, and became interested in astronomy.
At this time, most scholars still agreed with Ptolemy and Aristotle that all heavenly bodies
revolve around Earth (a geocentric model).
But other views were being considered. Nicolaus Copernicus claimed that all bodies revolve
around the Sun (a heliocentric model). Danish astronomer Tycho Brahe believed that Earth
was fixed but other planets orbited around the Sun.
In 1597, Galileo read a book by German astronomer Johannes Kepler that argued for a
heliocentric universe. Galileo wrote a letter to Kepler, saying he agreed, but was keeping
quiet, because he didn’t want to be mocked.
Galileo looks at the sky
Galileo’s first known astronomical observation occurred in 1604, when a supernova was
visible in the sky. A supernova is the explosive death of a large star.
Aristotle had said that no change could ever take place in the heavens. This event proved
him wrong. From then on, Galileo began to observe the sky, perform experiments, and make
his own conclusions.
In 1609, the Dutch had made an early telescope. A friend who saw it described it to Galileo
as having two lenses, one on each end of a 4-foot tube. Within about a month, Galileo had
made a telescope three times as powerful as the Dutch device. Galileo continued to work on
his telescope, making his own lenses.
Using the telescope, Galileo saw four moons orbiting Jupiter. This contradicted Ptolemy’s
idea that the Earth is the center of all orbiting bodies.
UNIT 2 —THE BIG BANG TEXT READER
16
Galileo published his findings in March 1610 as The Starry Messenger. The general public
was excited by his work. However, most philosophers and astronomers disagreed with
Galileo and said the moons weren’t really there.
Galileo stopped teaching and became mathematician for the royal family in Florence. It was
there that he began to observe Venus.
His observations demonstrated that Venus orbits the Sun. This proved Copernicus right and
Ptolemy wrong. Galileo believed that the Earth also orbits the Sun, but he had not proved it
yet.
The Inquisition targets Galileo
In the 16th century, the Catholic Church was facing many problems. Some people broke
from the Church because of a disagreement and became Protestants. Printers in many
European cities helped ideas spread quickly. Some of these ideas went against the
teachings of the Church.
To fight the spread of these ideas, the Pope set up a system of tribunals, or courts. It was
called the Inquisition.
In 1616, Inquisition authorities banned Copernicus’s book On the Revolutions of the
Celestial Spheres because it argued for a Solar System with the Sun at the center. They
also banned any other books that agreed with Copernicus, which included Galileo’s work.
Galileo traveled to Rome. He thought the Church was making a mistake that would hurt its
reputation. He believed the Catholic Church should keep science and religion completely
separate. The Church did not agree with Galileo. In the end, he agreed to obey the ban.
Galileo got permission from Pope Urban II to write a book, but he was not allowed to take
sides in the Earth versus Sun debate. Galileo worked on his book for six years. In the book,
one character argued for a heliocentric model, and another character argued for a
geocentric model. A third character was a regular person, listening to both sides.
The book appeared in Florence in March 1632. In August, an order came from the Roman
Inquisition to stop all sales.
Leaders in the Catholic Church felt that Galileo’s book was arguing for a heliocentric model,
even though the book wasn’t supposed to take sides.
In September 1632, Galileo was charged with “heresy” — disagreeing with the Church. He
was ordered to come to Rome for a trial.
Galileo tried to argue that his book showed both sides, but finally admitted that maybe the
book leaned toward the Sun-centered argument.
He was threatened with torture. He had to publicly admit he was wrong. His book was
banned.
Legend has it that as Galileo left the courtroom he whispered, “Eppur si muove [Still it
(Earth) moves],” but this was most likely invented later.
UNIT 2 —THE BIG BANG TEXT READER
17
Galileo was crushed by the harsh verdict. The Inquisition put him under house arrest at his
villa outside Florence. He was ill with a hernia, heart palpitations, and insomnia. A few
months after his return home, his older daughter, Maria Celeste, who he was very close to,
died.
The following year, Galileo’s book was published in Latin in France, outside the grasp of the
Catholic Inquisition. This allowed his ideas to reach a wide audience.
Blindness and a legacy of truth
Galileo bounced back from these serious setbacks. In 1637, he wrote a book summarizing
all his ideas. The book was translated into English, and Isaac Newton read it in 1666.
By 1638, Galileo had become totally blind. He wrote many letters by dictating them to others.
He died on January 9, 1642, in Florence, at the age of 77.
The Catholic Church didn’t end the ban on Galileo’s book for 200 years — not until 1835. In
1992, Pope John Paul II expressed regret at how the Church treated Galileo.
Galileo’s own insights about his blindness may be the best way to remember him. The
following lines have been adapted from a letter he wrote to a friend:
Well, your friend Galileo has been blind these last few months. Through my remarkable
discoveries and observations, I have greatly expanded our past ideas of our Universe. But
now, the whole Universe for me is shrunk down to my own sensations — what I can hear,
touch, smell, taste...
Galileo Galilei: The Father of Modern Observational Astronomy
(780L)
By Cynthia Stokes Brown, adapted by Newsela
Galileo Galilei was an Italian scholar who invented a telescope. With it, he collected
evidence of a Sun-centered Solar System.
Youth and education
Galileo Galilei was born in Pisa, Italy, in 1564. He was the first of seven children. Galileo’s
father was a musician — a lute player — from a noble background.
Galileo's wish was to become a priest, but his father pushed him to study medicine. He
attended the University of Pisa.
University courses at this time were based on Aristotle’s teachings. But Galileo made clever
observations and began to question some of Aristotle’s ideas.
For example, Aristotle taught that objects of different sizes fall at different speeds. Galileo
observed hailstones all hitting the ground at the same time. He decided Aristotle was wrong.
UNIT 2 —THE BIG BANG TEXT READER
18
Is the Earth or the Sun at the center of it all?
Galileo became a professor of mathematics. He also gave private lessons in architecture,
surveying, and mechanics. He also began studying tides, and became interested in
astronomy.
Most scholars at this time still agreed with Ptolemy and Aristotle that all heavenly bodies
revolve around Earth. Their view was called a geocentric model.
But other views were being considered. Nicolaus Copernicus claimed that all bodies revolve
around the Sun. His was called a heliocentric model. Astronomer Tycho Brahe believed that
Earth stayed still but other planets orbited around the Sun.
In 1597, Galileo read a book by German astronomer Johannes Kepler that argued for a
heliocentric universe. Galileo wrote a letter to Kepler saying he agreed, but was keeping
quiet. He didn’t want to be mocked for his ideas.
Galileo looks at the sky
Galileo observed a remarkable event in 1604, when a large star died in an explosion. It's
called a supernova.
Aristotle had said that no change could ever take place in the heavens. The supernova
proved him wrong.
From then on, Galileo began to observe the sky. He performed experiments and made his
own conclusions.
In 1609, the Dutch made an early telescope. A friend who saw it described it to Galileo. He
reported that it had two lenses, one on each end of a 4-foot tube. Within about a month,
Galileo had made a telescope three times as powerful as the Dutch device. Galileo
continued to work on his telescope, making his own lenses.
Using the telescope, Galileo saw four moons orbiting Jupiter. This contradicted Ptolemy’s
idea that the Earth is the center of all orbiting bodies.
Galileo published his findings in March 1610 as The Starry Messenger. The general public
was excited by what he wrote. However, most philosophers and astronomers disagreed with
Galileo. They said the moons weren’t really there.
Galileo stopped teaching and became a mathematician for the royal family in Florence. It
was there that he began to observe Venus.
His observations demonstrated that Venus orbits the Sun. This proved Copernicus right and
Ptolemy wrong. Galileo believed that the Earth also orbits the Sun, but he had not proved it
yet.
The Inquisition targets Galileo
In the 16th century, the Catholic Church was facing many problems. Some people separated
from the Church because of a disagreement and became Protestants. Printers in many
UNIT 2 —THE BIG BANG TEXT READER
19
European cities helped ideas spread quickly. Some of these ideas went against the
teachings of the Catholic Church.
To fight the spread of these ideas, the Pope set up a system of courts. It was called the
Inquisition.
In 1616, the Inquisition banned Copernicus’s book because it argued for a Solar System with
the Sun at the center. The Church also banned Galileo’s book because he agreed with
Copernicus.
Galileo traveled to Rome. He thought the Church was making a mistake that would hurt its
reputation. He believed the Catholic Church should keep science and religion completely
separate. The Church did not agree with Galileo. In the end, he agreed to obey the ban.
Galileo got permission from Pope Urban II to write a book, as long as he didn’t take sides in
the Earth versus Sun debate. Galileo worked on his book for six years. In the book, one
character argues for a heliocentric model, and another character argues for a geocentric
model. The third character was a regular person, listening to both sides.
The book appeared in Florence in March 1632. In August, an order came from the Roman
Inquisition to stop all sales. The Catholic Church felt that Galileo’s book was arguing for a
Sun-centered model.
In September 1632, Galileo was charged with “heresy” — disagreeing with the Church. He
was ordered to come to Rome for a trial.
Galileo tried to argue that his book showed both sides. Finally, he admitted that maybe the
book leaned toward the Sun-centered argument. He was threatened with torture. He had to
publicly admit he was wrong. His book was banned.
Galileo was crushed by the harsh verdict. The Inquisition put him under house arrest at his
villa outside Florence. He suffered from many illnesses. A few months after his return home,
his beloved, older daughter died.
The following year, Galileo’s book was published in France, outside the grasp of the Catholic
Inquisition. This allowed his ideas to reach a wide audience.
Blindness and a legacy of truth
Galileo bounced back from these serious difficulties. In 1637, he wrote a book summarizing
all his ideas. The book was translated into English, and Isaac Newton read it in 1666.
By 1638, Galileo had become totally blind. He wrote many letters by dictating them to others.
He died on January 9, 1642, in Florence, at the age of 77.
It took the Catholic Church 200 years to lift the ban on Galileo’s book. In 1992, Pope John
Paul II apologized for how the Church treated Galileo.
Galileo may be best remembered by his own self-reflection. Here is an adapted section of a
letter he wrote about his blindness:
UNIT 2 —THE BIG BANG TEXT READER
20
Well, your friend Galileo has been blind these last few months. Through my remarkable
discoveries and observations, I have greatly expanded our past ideas of our Universe. But
now, the whole Universe for me is shrunk down to my own sensations — what I can hear,
touch, smell, taste...
Copernicus
Copernicus was a Catholic, Polish astronomer who declared that the Sun — not the Earth —
was at the center of the Universe. His ideas launched modern astronomy, and started a
scientific revolution.
Nicolaus Copernicus: A Renaissance man who started a scientific
revolution (1180L)
By Cynthia Stokes Brown
In the middle of the 16th century, a Catholic, Polish astronomer, Nicolaus Copernicus,
synthesized observational data to formulate a comprehensive, Sun-centered cosmology,
launching modern astronomy and setting off a scientific revolution.
Renaissance man
Have you ever heard the expression “Renaissance man?” The phrase describes a welleducated person who excels in a wide variety of subjects or fields. The Renaissance is the
name for a period in European history, the 14th through the 17th centuries, when the
continent emerged from the “Dark Ages” with a renewed interest in the arts and sciences.
European scholars were rediscovering Greek and Roman knowledge, and educated
Europeans felt that humans were limitless in their thinking capacities and should embrace all
types of knowledge.
Nicolaus Copernicus fulfilled the Renaissance ideal. He became a mathematician, an
astronomer, a church jurist with a doctorate in law, a physician, a translator, an artist, a
Catholic cleric, a governor, a diplomat, and an economist. He spoke German, Polish, and
Latin, and understood Greek and Italian.
Family and studies
Nicolaus was born February 19, 1473 to wealthy parents who lived in the center of what is
now Poland. His father, named Nicolaus Koppernigk, was a copper merchant from Krakow,
and his mother, Barbara Watzenrode, was the daughter of a wealthy local merchant.
Nicolaus was the youngest of four children; he had a brother and two sisters. His father died
when he was 10 and his mother at about the same time. His mother’s brother adopted
Nicolaus and his siblings and secured the future of each of them.
This maternal uncle, Lucas Watzenrode, was a wealthy, powerful man in Warmia, a small
province in northeast Poland under the rule of a prince-bishop. Since 1466 Warmia had
been part of the kingdom of Poland, but the king allowed it to govern itself. Watzenrode
UNIT 2 —THE BIG BANG TEXT READER
21
became the prince-bishop in Warmia when Copernicus was 16. Three years later he sent
Copernicus and his brother to the University of Krakow, where Copernicus studied from
1492 to 1496. He was in his first year at the university when Columbus sailed to a continent
that was then unknown in Europe. Copernicus changed his last name, Koppernigk, to its
Latin version while at the university, since scholars used Latin as their common language.
At Krakow Copernicus studied mathematics and Greek and Islamic astronomy. After
studying at Krakow, Copernicus’s uncle sent him to Italy, where he studied law at the
University of Bologna for four years, and then medicine at the University of Padua for two
years. These were two of the earliest and best European universities and Copernicus had to
travel two months by foot and horseback to reach Italy.
At these universities, Copernicus began to question what he was taught. For example, his
professors at Krakow taught about both Aristotle’s and Ptolemy’s views of the Universe.
However, Copernicus became aware of the contradictions between Aristotle’s theory of the
Earth, the Sun and the planets as a system of concentric spheres and Ptolemy’s use of
eccentric orbits and epicycles. Even though his professors believed that the Earth was in the
center of the Universe and it did not move, Copernicus began to question those ideas. While
at the University of Padua, there is some evidence that he had already developed the idea of
a new system of cosmology based on the movement of the Earth.
Copernicus returned to Warmia in 1503, at age 30, to live in his uncle’s castle and serve as
his secretary and physician. He stayed at this job, which gave him free time to continue his
observations of the heavens, until 1510, two years before his uncle’s death.
Life as a canon
Thanks to help from his uncle, Copernicus was elected in 1497 a canon of the cathedral in
Frombork, a town in Warmia on the Baltic Sea coast. Canons were responsible for
administering all aspects of a cathedral. Copernicus did not assume his position there until
1510, when he took a house outside the cathedral walls and an apartment inside a tower of
the fortifications. He had many duties as canon, including mapmaking, collecting taxes and
managing the money, serving as a secretary, and practicing medicine. He led a halfreligious, half-secular life and still managed to continue his astronomical observations from
his tower apartment. He conducted these with devices that looked like wooden yardsticks
joined together, set up to measure the angular altitude of stars and planets and the angles
between two distant bodies in the sky. He had a simple metal tube to look through, but no
telescope had yet been invented.
By 1514 Copernicus had written a short report that he circulated among his astronomyminded friends. This report, called the Little Commentary, expounded his heliocentric theory.
He omitted mathematical calculations for the sake of brevity, but he confidently asserted that
the Earth both revolved on its axis and orbited around the Sun. This solved many of the
problems he found with Ptolemy’s model, especially the lack of uniform circular motion.
By 1531 the bishop-prince of Warmia believed that Copernicus had a mistress, Anna
Schilling, whom he called his housekeeper. The next bishop-prince worked persistently to
force Copernicus to give up his companion. Lutheran Protestantism was springing up
UNIT 2 —THE BIG BANG TEXT READER
22
nearby, as cities, dukes, and kings renounced their loyalty to the Catholic Church. The
Catholic Church responded by trying to enforce more obedience to its rules. However,
Copernicus and Schilling managed to keep seeing each other, although not living together,
until much later when she moved to the city of Gdansk.
A heliocentric theory
By 1532 Copernicus had mostly completed a detailed astronomical manuscript he had been
working on for 16 years. He had resisted publishing it for fear of the ensuing controversy and
out of hope for more data. Finally, in 1541, the 68-year-old Copernicus agreed to publication,
supported by a mathematician friend, Georg Rheticus, a professor at the University of
Wittenberg, in Germany. Rheticus had traveled to Warmia to work with Copernicus, and then
took his manuscript to a printer in Nuremberg, Johannes Petreius, who was known for
publishing books on science and mathematics. Copernicus gave his master work the Latin
title De Revolutionibus Orbium Coelestium(translated to English as On the Revolutions of
the Celestial Spheres).
In this work Copernicus began by describing the shape of the Universe. He provided a
diagram to help the reader. In the diagram he showed the outer circle that contained all the
fixed stars, much further away than previously believed. Inside the fixed stars were Saturn,
then Jupiter and Mars, then Earth, Venus, and Mercury, all in circular orbits around the Sun
in the center.
He calculated the time required for each planet to complete its orbit and was off by only a bit.
Copernicus’s theory can be summarized like this:
The center of the Earth is not the center of the Universe, only of Earth’s gravity and of the
lunar sphere.
The Sun is fixed and all other spheres revolve around the Sun. Copernicus retained the idea
of spheres and of perfectly circular orbits. In fact, the orbits are elliptical, which the German
astronomer Johannes Kepler demonstrated in 1609.
Earth has more than one motion, turning on its axis and moving in a spherical orbit around
the sun.
The stars are fixed but appear to move because of the Earth’s motion.
Death and legacy
Legend has it that Copernicus, in a sickbed when his great work was published, awoke from
a stroke-induced coma to look at the first copy of his book when it was brought to him. He
was able to see and appreciate his accomplishment, and then closed his eyes and died
peacefully, on May 24, 1543. Thus he avoided both scorn and praise.
Copernicus was thought to be buried in the cathedral at Frombork, but no marker existed.
Some of his bones were finally identified there, with a DNA match from a strand of his hair
found in a book owned by him, and in 2010 he was given a new burial in the same spot, now
marked with a black granite tombstone.
UNIT 2 —THE BIG BANG TEXT READER
23
The Roman Catholic Church waited seven decades to take any action against On the
Revolutions of the Celestial Spheres. Why it waited so long has been the subject of much
debate. In 1616 the Church issued a decree suspending On the Revolutions of the Celestial
Spheres until it could be corrected and prohibiting any work that defended the movement of
Earth. A correction appeared in 1620, and in 1633 Galileo Galilei was convicted of grave
suspicion of heresy for following Copernicus’s position.
Scholars did not generally accept the heliocentric view until Isaac Newton, in 1687,
formulated the Law of Universal Gravitation. This law explained how gravity would cause the
planets to orbit the much more massive Sun and why the small moons around Jupiter and
Earth orbited their home planets.
How long did it take for Copernicus’s ideas to reach the general public? Does anyone
nowadays still believe the apparent evidence before their eyes that the Sun moves around
the Earth to set and rise? Almost everyone learns in childhood that, despite appearances,
the Earth moves around the Sun.
Copernicus’s model asked people to give up thinking that they lived in the center of the
Universe. For him the thought of the Sun illuminating all of the planets as they rotated
around it had a sense of great beauty and simplicity.
Nicolaus Copernicus: A Renaissance man who started a scientific
revolution (1070L)
By Cynthia Stokes Brown, adapted by Newsela
In the middle of the 16th century, a Catholic, Polish astronomer, Nicolaus Copernicus, used
observational data to diagram a Sun-centered view of the Universe. His work launched
modern astronomy and set off a scientific revolution.
Renaissance man
Have you ever heard the expression “Renaissance man?” The phrase describes a welleducated person who excels in a wide variety of subjects or fields. The Renaissance is the
name for a period in European history, the 14th through the 17th centuries, when the
continent emerged from the Dark Ages with a renewed interest in the arts and sciences.
European scholars were rediscovering Greek and Roman knowledge, and educated
Europeans felt that humans were limitless in their thinking capacities and should embrace all
types of knowledge.
Nicolaus Copernicus was a true Renaissance man. He became a mathematician, an
astronomer, a church judge with a doctorate in law, a physician, a translator, an artist, a
Catholic cleric, a governor, a diplomat, and an economist. He spoke German, Polish, and
Latin, and understood Greek and Italian.
UNIT 2 —THE BIG BANG TEXT READER
24
Family and studies
Copernicus was born to wealthy parents in what is now Poland on February 19, 1473. Both
his parents died when he was young. His wealthy, powerful uncle adopted him and his
siblings.
Copernicus studied mathematics and astronomy at the University of Krakow from 1492 to
1496. He changed his last name, Koppernigk, to its Latin version while at the university,
since scholars used Latin as their common language.
He also studied law at the University of Bologna and medicine at the University of Padua. It
took two months to travel from Poland to Italy by foot and horseback, but the two schools in
Italy were among the best in the world at that time.
As a student, Copernicus began to question what he was taught. He learned Aristotle’s and
Ptolemy’s views of the Universe. Even though his professors believed that the Earth was at
the center of the Universe and it did not move, Copernicus began to question those ideas.
Even as a young university student, there is evidence that Copernicus was beginning to
envision a Universe where the Earth moved.
Copernicus returned to Poland in 1503, at age 30, to live in his uncle’s castle and serve as
his secretary and physician. He stayed at this job, which gave him free time to continue his
observations of the heavens, until 1510, two years before his uncle’s death.
Life as a canon
In 1497, Copernicus was elected canon of the cathedral in Frombork. Canons were
responsible for administering all aspects of a cathedral. He had many duties as canon,
including mapmaking, collecting taxes and managing the money, serving as a secretary, and
practicing medicine.
He led a half-religious, half-secular life and still managed to continue his astronomical
observations from his tower apartment. He conducted these with devices that looked like
wooden yardsticks joined together, set up to measure the angular altitude of stars and
planets and the angles between two distant bodies in the sky. He had a simple metal tube to
look through, but no telescope had yet been invented.
By 1514, Copernicus had written a short report that he gave to his astronomy-minded
friends. This report, called the Little Commentary, explained his heliocentric theory. In it,
Copernicus confidently said that the Earth both revolved on its axis and orbited around the
Sun.
A heliocentric theory
Copernicus worked on a detailed astronomical book for 16 years. He didn’t want to publish it
because he was afraid of the huge controversy it would produce. He also hoped to gather
more data.
UNIT 2 —THE BIG BANG TEXT READER
25
Finally, in 1541, when he was 68, he agreed to publish it after a mathematician friend helped
convince him. Copernicus gave his master work the title On the Revolutions of the Celestial
Spheres.
In this work, Copernicus began by describing the shape of the Universe. He provided a
diagram to help the reader. In the diagram, he showed the outer circle that contained all the
fixed stars, much further away than previously believed. Inside the fixed stars were Saturn,
then Jupiter, and Mars, then Earth, Venus, and Mercury, all in circular orbits around the Sun
in the center.
He calculated the time required for each planet to complete its orbit, and was off by only a
bit. Copernicus’s theory can be summarized like this:
The center of the Earth is not the center of the Universe, only of Earth’s gravity and of the
Moon. The Sun is fixed and all other spheres revolve around the Sun. Copernicus kept the
idea of spheres and of perfectly circular orbits. In fact, the orbits are elliptical, which the
German astronomer Johannes Kepler demonstrated in 1609. Earth has more than one
motion, turning on its axis and moving in a spherical orbit around the sun.
The stars are fixed, but appear to move because of the Earth’s motion.
Death and legacy
Legend has it that Copernicus, in a sickbed when his great work was published, awoke from
a coma to look at the first copy of his book when it was brought to him. He was able to see
and appreciate his accomplishment, and then closed his eyes and died peacefully, on May
24, 1543. He didn’t live to hear the praise or criticism of his ideas.
The Catholic Church waited seven decades to take any action against On the Revolutions of
the Celestial Spheres. Why it waited so long has been the subject of much debate. In 1616,
the church banned the book and any other work that defended the movement of the Earth.
In 1633, Galileo Galilei was convicted of defying Church teachings for following Copernicus’s
position.
Scholars did not generally accept the heliocentric view until Isaac Newton, in 1687,
formulated the Law of Universal Gravitation. This law explained how gravity would cause the
planets to orbit the much more massive Sun, and why the small moons around Jupiter and
Earth orbited their home planets.
How long did it take for Copernicus’s ideas to reach the general public? Does anyone
nowadays still believe the apparent evidence before their eyes that the Sun moves around
the Earth to set and rise? Almost everyone learns in childhood that, despite appearances,
the Earth moves around the Sun.
Copernicus’s model asked people to give up thinking that they lived in the center of the
Universe. For him, the thought of the Sun illuminating all of the planets as they rotated
around it had a sense of great beauty and simplicity.
UNIT 2 —THE BIG BANG TEXT READER
26
Nicolaus Copernicus: A Renaissance man who started a scientific
revolution (920L)
By Cynthia Stokes Brown, adapted by Newsela
Copernicus was a Polish astronomer who declared that the Sun — not the Earth — was at
the center of the Universe. His ideas launched modern astronomy, and started a scientific
revolution.
Renaissance man
Have you ever heard the expression “Renaissance man?” The phrase describes a welleducated person who does well in many different fields. The Renaissance is the name for a
period in European history, the 14th through the 17th centuries, when the continent emerged
from the Dark Ages.
The Renaissance brought a renewed interest in the arts and sciences to Europe.
Nicolaus Copernicus was a true Renaissance man. He became a mathematician, an
astronomer, a church judge with a doctorate in law, a physician, a translator, an artist, an
official in the Catholic Church, a governor, a diplomat, and an economist. He spoke German,
Polish, and Latin, and understood Greek and Italian.
Family and studies
Copernicus was born February 19, 1473 to wealthy parents who both died when he was
young. He and his siblings were adopted by his rich and powerful uncle.
He studied mathematics and astronomy at the University of Krakow from 1492 to 1496. He
changed his last name, Koppernigk, to its Latin version while at the university, since scholars
used Latin as their common language.
Copernicus also studied law at the University of Bologna and medicine at the University of
Padua. These two schools were among the best in the world at that time. It was not an easy
journey, though. It took two months to travel from Poland to Italy by foot and horseback
As a student, Copernicus began to question what he was taught. He learned Aristotle’s and
Ptolemy’s views of the Universe. His professors believed that the Earth was at the center of
the Universe and it did not move. Copernicus began to question those ideas.
Even as a young university student, Copernicus was beginning to see a Universe where the
Earth moved.
Life at the cathedral
In 1497, Copernicus was elected canon of the cathedral in Frombork. Canons were
responsible for all aspects of a cathedral. He had many duties as canon, including
mapmaking, collecting taxes and managing the money, serving as a secretary, and
practicing medicine.
UNIT 2 —THE BIG BANG TEXT READER
27
His life was half-religious and half-scientific. He continued making astronomical observations
from his tower apartment.
He didn’t have a telescope, because the telescope hadn’t been invented yet. Instead, he
looked through a simple metal tube. He also had a device that looked like two wooden
yardsticks joined together. He used it to measure the angles of stars and planets in the sky.
By 1514, Copernicus had written a short report that explained his heliocentric theory. In it,
Copernicus confidently said that the Earth both revolved on its axis and orbited around the
Sun.
A heliocentric theory
Copernicus worked on a major astronomical book for 16 years. He didn’t want to publish it
because he was afraid of the fierce debate it would spark. He also hoped to gather more
data.
In 1541, when he was 68, he agreed to publish it after a mathematician friend helped
convince him. Copernicus titled his master work On the Revolutions of the Celestial
Spheres.
In this work, Copernicus began by describing the shape of the Universe. He provided a
diagram to help the reader. In the diagram, he showed the outer circle that contained all the
fixed stars, much further away than previously thought. Inside the fixed stars were Saturn,
then Jupiter, and Mars, then Earth, Venus, and Mercury. All of these planets made circular
orbits around the Sun in the center.
He calculated the time required for each planet to complete its orbit, and was off by only a
bit. Copernicus’s theory can be summarized like this:
The center of the Earth is not the center of the Universe, only of Earth’s gravity and of the
lunar sphere. The Sun is fixed, and all other spheres revolve around the Sun. Earth has
more than one motion, turning on its axis and moving in a spherical orbit around the Sun.
The stars are fixed, but appear to move because of the Earth’s motion.
Death and legacy
Legend has it that Copernicus was on his deathbed, in a coma, when his great work was
published. He awoke from the coma to see the first copy of his book. After he had seen and
appreciated his accomplishment, he died peacefully on May 24, 1543. He didn’t live to hear
the praise or criticism of his ideas.
The Catholic Church banned Copernicus’s book more than 70 years later. It also banned
any other book that agreed with Copernicus’s heliocentric argument. In 1633, Galileo Galilei
was convicted of defying Church teachings for following Copernicus’s position.
Copernicus’s heliocentric model was not widely accepted until Isaac Newton developed the
Law of Universal Gravitation in 1687. This law explained how gravity would cause the
planets to orbit the Sun, which is much larger than the Earth. It also explained why small
moons around Jupiter and Earth orbited their home planets.
UNIT 2 —THE BIG BANG TEXT READER
28
It appears that the Sun rises each morning and sets every night. But really, it is the Earth,
not the Sun, that is moving. Copernicus asked people to give up thinking that they lived in
the center of the Universe.
For him, the idea of the Sun shining on all the planets as they rotated around it had great
beauty and simplicity.
Nicolaus Copernicus: A Renaissance man who started a scientific
revolution (760L)
By Cynthia Stokes Brown, adapted by Newsela
Copernicus was a Polish astronomer who said that the Sun – not the Earth – was at the
center of the Universe. His ideas launched a scientific revolution.
Renaissance man
Have you ever heard the expression “Renaissance man?” This term describes a person who
is very good at many different things.
Nicolaus Copernicus was not only an astronomy genius. He was also a mathematician, a
church judge, a doctor, a translator, an artist, an official in the Catholic Church, a governor, a
diplomat, and an economist. He spoke German, Polish, and Latin, and understood Greek
and Italian.
Family and studies
Copernicus was born February 19, 1473 to wealthy parents who both died when he was
young. He and his siblings were adopted by his rich and powerful uncle.
He studied mathematics and astronomy at the University of Krakow from 1492 to 1496.
While there he changed his original last name, Koppernigk, to its Latin version. Latin was the
common language of scholars at the time.
Copernicus also studied law and medicine in Italy. The journey from Poland to Italy took two
months by foot and horseback. But the universities in Italy were some of the best in the
world at the time.
As a student, Copernicus began to question what he was taught. His professors taught him
Aristotle’s and Ptolemy’s views: the Earth was at the center of the Universe. It did not move.
Copernicus began to develop his theory that the Sun was at the center of the universe while
he was a student.
Life at the cathedral
Copernicus became canon of Frombork cathedral in 1497. He had many duties as canon.
These included mapmaking, collecting taxes, serving as a secretary, and practicing
medicine.
UNIT 2 —THE BIG BANG TEXT READER
29
He continued his study of the skies. He made astronomical observations from his tower
apartment.
Copernicus didn’t have a telescope, because the telescope hadn’t been invented yet.
Instead, he looked through a simple metal tube. He also had a device that looked like two
wooden yardsticks joined together. He used it to measure the angles of stars and planets in
the sky.
Based on his observations, he wrote a short report in which he explained his heliocentric
theory. Copernicus confidently said that the Earth both turned on its axis and orbited around
the Sun.
A heliocentric theory
It took Copernicus 16 years to write his masterwork on astronomy. Even then, he didn’t want
to publish it. He was afraid of the huge controversy it would create. He also wanted time for
more research.
Finally, a mathematician friend convinced Copernicus to publish the book. He was 68.
The book was called On the Revolutions of the Celestial Spheres. In it, Copernicus
described the shape of the Universe. He provided a diagram to help readers. In the diagram,
we see the Sun at the center. Orbiting around the Sun are the planets, including Earth. On
the outside are the fixed stars.
Copernicus’s theory can be summarized like this:
The center of the Earth is not the center of the Universe, only of Earth’s gravity and the
moon. The Sun doesn’t move, and all other spheres revolve around the Sun. Earth has more
than one motion. It turns on its axis and moves in a spherical orbit around the Sun. The stars
appear to move, but really it is the Earth that is moving.
Death and legacy
Legend says that Copernicus was on his deathbed when his great work was published. He
woke from a coma to see and appreciate his accomplishment. He died peacefully on May
24, 1543. He didn’t live to hear any praise or criticism of his ideas.
The Catholic Church banned Copernicus’s book more than 70 years later. It also banned
any other book that agreed with Copernicus’s heliocentric argument — Galileo Galilei’s for
example.
Copernicus’s heliocentric model wasn’t widely accepted for hundreds of years.
Isaac Newton’s laws of gravity helped to confirm Copernicus’s theories. The laws explained
why planets would orbit the Sun and not the Earth. Because the Sun is much larger, the pull
of its gravity is stronger.
It appears that the Sun rises each morning and sets every night. But really, it is the Earth,
not the Sun, that is moving. Copernicus asked people to give up thinking that they lived in
the center of the Universe.
UNIT 2 —THE BIG BANG TEXT READER
30
For him, the idea of the Sun shining on all the planets as they rotated around it had great
beauty and simplicity.
Newton
A falling apple plants the seed for the discovery of the Law of Universal Gravitation.
Sir Isaac Newton: Physics, Gravity, and Laws of Motion (1240L)
By Cynthia Stokes Brown
Newton developed the three basic laws of motion and the theory of universal gravity, which
together laid the foundation for our current understanding of physics and the Universe.
Early life and education
Isaac Newton was born prematurely on January 4, 1643, in Lincolnshire, England. His father
had died before his birth. When he was 3, his mother remarried and left him with his
grandparents on a farm, while she moved to a village a mile and a half away from him. He
grew up with few playmates, and amused himself by contemplating the world around him.
His mother returned when Newton was 11 years old and sent him to King’s School. Rather
than playing after school with the other boys, Newton spent his free time making wooden
models, kites of various designs, sundials, even a water clock. When his mother, who was
hardly literate, took him out of school at 15 to turn him into a farmer, the headmaster, who
recognized where Newton’s talents lay, prevailed on her to let Newton return to school.
Early discoveries
Newton attended Cambridge University from 1661 to 1665. The university temporarily closed
soon after he got his degree because people in urban areas were dying from the plague.
Newton retreated to his grandparents’ farm for two years, during which time he proved that
“white” light was composed of all colors, and started to figure out calculus and universal
gravitation — all before he was 24 years old.
It was on his grandparents’ farm that Newton sat under the famous apple tree and watched
one of its fruits fall to the ground. He wondered if the force that pulled the apple to the
ground could extend out to the Moon and keep it in its orbit around Earth. Perhaps that force
could extend into the Universe indefinitely.
After the plague subsided, Newton returned to Cambridge to earn his master’s degree and
become a professor of mathematics there. His lectures bored many of his students, but he
continued his own thinking and experiments, undaunted. When his mother died, he inherited
enough wealth to leave his teaching job and move to London, where he became the
president of the Royal Society of London for Improving Natural Knowledge, the top
organization of scientists in England.
UNIT 2 —THE BIG BANG TEXT READER
31
Laws of motion and gravity
Newton’s most important book was written in Latin; its title was translated as Mathematical
Principles of Natural Philosophy. It was published in 1687. The book proved to be one of the
most influential works in the history of science. In its pages, Newton asserted the three Laws
of Motion, elaborated Johannes Kepler’s Laws of Motion, and stated the Law of Universal
Gravitation. The book is primarily a mathematical work, in which Newton developed and
applied calculus, the mathematics of change, which allowed him to understand the motion of
celestial bodies.
To reach his conclusions, he also used accurate observations of planetary motion, which he
made by designing and building a new kind of telescope, one that used mirrors to reflect,
rather than lenses to refract, light.
Newton’s three Laws of Motion
1. Every body continues at rest or in motion in a straight line unless compelled to
change by forces impressed upon it. Galileo Galilei first formulated this, and Newton
recast it.
2. Every change of motion is proportional to the force impressed and is made in the
direction of the straight line in which that force is impressed. A planet would continue
outward into space but is perfectly balanced by the Sun’s inward pull, which Newton
termed “centripetal” force.
3. To every action there is always opposed an equal reaction, or the mutual action of
two bodies on each other is always equal and directed to contrary parts.
Law Of Universal Gravitation
Putting these laws together, Newton was able to state the Law of Universal Gravitation:
“Every particle of matter attracts every other particle with a force proportional to the product
of the masses of the two particles and inversely proportional to the square of the distance
between them.” Stated more simply, the gravitational attraction between two bodies
decreases rapidly as the distance between them increases.
This calculation proved powerful because it presented the Universe as an endless void filled
with small material bodies moving according to harmonious, rational principles. Newton
understood gravity as a universal property of all bodies, its force dependent only on the
amount of matter contained in each body. Everything, from apples to planets, obeys the
same unchanging laws.
By combining physics, mathematics, and astronomy, Newton made a giant leap in human
understanding of Earth and the cosmos. Newton’s mathematical method for dealing with
changing quantities is now called calculus. He did not publish his method, but solved
problems using it. Later, the German scientist Gottfried Wilhelm von Leibniz also worked out
calculus, and his notation proved easier to use. Newton accused Leibniz, in a nasty dispute,
of stealing his ideas, but historians now believe that each invented calculus independently.
UNIT 2 —THE BIG BANG TEXT READER
32
Newton was made a knight by Queen Anne in 1705. At his death in 1727, he was buried in
London’s Westminster Abbey. Shortly before he died, Newton remarked:
I do not know what I may appear to the world, but to myself I seem to have been only like a
boy playing on the seashore and diverting myself in now and then finding a smoother pebble
or prettier shell than ordinary, while the great ocean of truth lay all undiscovered before me.
Sir Isaac Newton: Physics, Gravity, and Laws of Motion (1030L)
By Cynthia Stokes Brown, adapted by Newsela
Newton developed the three basic laws of motion and the theory of universal gravity. Today,
these discoveries form the basis of our understanding of physics and the Universe.
Early life and education
Isaac Newton was born prematurely on January 4, 1643. After his father died and his mother
moved away, he grew up with his grandparents on a farm. As a child he had few playmates,
and amused himself by contemplating the world around him.
At school, Newton didn’t spend his free time after school playing with the other boys.
Instead, he made wooden models, kites, sundials, and even a water clock.
When he was 15, his mother took him out of school to become a farmer. But the director of
his school recognized Newton’s talents and convinced his mother to let him return to school.
Newton attended Cambridge University from 1661 to 1665. The university temporarily closed
soon after he got his degree because people in urban areas were dying from the plague.
Early discoveries
Newton retreated to his grandparents’ farm for two years. During this time, he proved that
“white” light was composed of all colors, and started to figure out calculus and universal
gravitation — all before he was 24 years old.
Newton was on his grandparents’ farm when he sat under the famous apple tree and
watched an apple fall to the ground.
He wondered if the force that pulled the apple to the ground could extend out to the Moon
and keep it in its orbit around Earth. Perhaps that force could extend into the Universe
indefinitely.
After the plague subsided, Newton returned to Cambridge. He earned his master’s degree
and became a professor of mathematics there. His lectures bored many of his students, but
he continued his own thinking and experiments, undaunted. Later, he became the president
of the Royal Society of London for Improving Natural Knowledge — the top organization of
scientists in England.
UNIT 2 —THE BIG BANG TEXT READER
33
Laws of motion and gravity
Newton’s most important book was written in Latin; its title was translated as Mathematical
Principles of Natural Philosophy and was published in 1687.
It proved to be one of the most influential works in the history of science. The book explained
Newton’s three Laws of Motion and the Law of Universal Gravitation.
Newton used advanced math and observation of the heavens to develop his laws. To track
the stars and planets, he used a new type of telescope that he designed and built himself.
Newton’s three Laws of Motion
1. An object at rest will stay at rest and an object in motion will stay in motion along a
straight line unless an external force is applied to it.
2. An object will accelerate if force is applied to it. The acceleration will happen in the
direction of the force. The acceleration will be less as the object gets bigger.
3. For every action there is always an equal and opposite reaction.
Putting these laws together, Newton was able to state the Law of Universal Gravitation:
“Every particle of matter attracts every other particle with a force proportional to the product
of the masses of the two particles and inversely proportional to the square of the distance
between them.”
Stated more simply, the gravitational attraction between two objects decreases rapidly as
the objects get farther apart.
This calculation proved powerful because it presented the Universe as an endless void filled
with small objects moving according to rational principles.
Everything, from apples to planets, obeys the same unchanging laws. By combining physics,
mathematics, and astronomy, Newton made a giant leap in human understanding of Earth
and the cosmos.
Calculus
Newton’s mathematical method for dealing with changing quantities is now called calculus.
Newton did not publish his method, but solved problems using it.
Later, the German scientist Gottfried Wilhelm von Leibniz also worked out calculus, and his
notation proved easier to use. Newton accused Leibniz, in a nasty dispute, of stealing his
ideas, but historians now believe that each invented calculus independently.
Newton was made a knight by Queen Anne in 1705. At his death in 1727, he was buried in
London’s Westminster Abbey. Shortly before he died, Newton remarked:
I do not know what I may appear to the world, but to myself I seem to have been only like a
boy playing on the seashore and diverting myself in now and then finding a smoother pebble
or prettier shell than ordinary, while the great ocean of truth lay all undiscovered before me.
UNIT 2 —THE BIG BANG TEXT READER
34
Sir Isaac Newton: Physics, Gravity, and Laws of Motion (950L)
By Cynthia Stokes Brown, adapted by Newsela
Newton developed the three basic laws of motion and the theory of universal gravity. Today,
these discoveries form the basis for our understanding of physics and the Universe.
Early life and education
Isaac Newton was born prematurely on January 4, 1643. He grew up with his grandparents
on a farm after his father died and his mother moved away.
As a child he had few playmates. He amused himself by thinking about the world around
him. At school, Newton didn’t play much with the other boys. Instead, he made wooden
models, kites, sundials, and even a water clock.
When he was 15, his mother took him out of school to become a farmer. But the director of
his school recognized the boy’s talents and convinced his mother to let him return to school.
Newton went Cambridge University from 1661 to 1665. The university temporarily closed
soon after he got his degree because people in European cities were dying from the plague.
Early discoveries
Newton moved back to his grandparents’ farm for two years. During this time, he proved that
“white” light was composed of all colors and started to figure out calculus and universal
gravitation. He did all this before he was 24 years old.
Newton was on his grandparents’ farm when he sat under the famous apple tree and
watched an apple fall to the ground.
He wondered if the force that pulled the apple to the ground could extend out to the Moon
and keep it in its orbit around Earth. Perhaps that force extended throughout the whole
Universe.
After the plague abated, Newton returned to Cambridge. He earned his master’s degree and
became a professor of mathematics there.
His lectures bored many of his students, but he continued his own thinking and experiments.
Later, he became the president of the Royal Society of London for Improving Natural
Knowledge — the top organization of scientists in England.
Laws of motion and gravity
Newton’s most important book was written in Latin; its English title was Mathematical
Principles of Natural Philosophy and was published in 1687.
It proved to be one of the most influential works in the history of science. The book explained
Newton’s three Laws of Motion and the Law of Universal Gravitation.
Newton used advanced math and observation of the heavens to develop his laws. To track
the stars and planets, he used a new type of telescope that he designed and built himself.
UNIT 2 —THE BIG BANG TEXT READER
35
Newton’s three Laws of Motion
1. An object at rest will stay at rest unless a force is applied to it. An object in motion will
stay in motion along a straight line unless an external force is applied to it.
2. An object will accelerate if force is applied to it. The acceleration will happen in the
direction of the force. The acceleration will be less as the object gets bigger.
3. For every action there is always an equal and opposite reaction.
Putting these laws together, Newton was able to state the Law of Universal Gravitation: the
gravitational pull between two objects decreases as the objects get farther apart.
Newton’s Universe was a powerful idea because it said that all objects move according to
rational principles.
Everything, from apples to planets, obeys the same unchanging laws. By combining physics,
mathematics, and astronomy, Newton made a giant leap in human understanding of Earth
and the cosmos.
Calculus
Newton came up with a new mathematical method for dealing with changing quantities. It is
now called calculus. Newton didn’t publish his method, he used it to solve problems.
Later, the German scientist Gottfried Wilhelm von Leibniz also worked out calculus. His
system was easier to use.
Newton accused Leibniz of stealing his ideas, but historians now believe that each invented
calculus independently.
Newton was made a knight by Queen Anne in 1705. At his death in 1727, he was buried in
London’s Westminster Abbey. Shortly before he died, Newton remarked:
I do not know what I may appear to the world, but to myself I seem to have been only like a
boy playing on the seashore and diverting myself in now and then finding a smoother pebble
or prettier shell than ordinary, while the great ocean of truth lay all undiscovered before me.
Sir Isaac Newton: Physics, Gravity, and Laws of Motion (780L)
By Cynthia Stokes Brown, adapted by Newsela
Newton developed the three basic laws of motion and the theory of universal gravity. His
work formed our understanding of physics and the Universe.
Early life and education
Isaac Newton was born on January 4, 1643, too soon before his due date. After his father
died and his mother moved away, he grew up with his grandparents on a farm.
As a child, he didn’t have many friends. He amused himself by thinking about the world
around him.
UNIT 2 —THE BIG BANG TEXT READER
36
At school, Newton didn’t play much with other students. Instead, he made wooden models,
kites, sundials, and even a water clock.
When he was 15, his mother took him out of school to become a farmer. But the director of
his school recognized his genius and convinced his mother to let him return to school.
Newton went Cambridge University from 1661 to 1665. He then moved back to his
grandparents’ farm for two years.
During this time, he proved that “white” light was made up of all colors. He also started to
figure out calculus and universal gravitation. He did all this before he was 24 years old.
Early discoveries
At his grandparents’ farm, Newton sat under the famous apple tree and watched an apple
fall to the ground.
He wondered if the force that pulled the apple to the ground could extend out to the Moon
and keep it in its orbit around Earth. Perhaps that force extended throughout the whole
Universe.
Newton became a professor of mathematics at Cambridge. His lectures bored many of his
students, but he didn’t care. He continued his own thinking and experiments.
Later, he became the president of the top organization of scientists in England.
Laws of motion and gravity
Newton’s most important book was written in Latin and published in 1687. Its English title
wasMathematical Principles of Natural Philosophy.
It was one of the most influential works in the history of science. The book explained
Newton’s three Laws of Motion and the Law of Universal Gravitation.
To develop his laws, Newton used advanced math. He also designed and built his own
telescope to study the heavens.
Newton’s three Laws of Motion
1. An object at rest will stay at rest unless a force is applied to it. An object in motion will
stay in motion along a straight line unless an external force is applied to it.
2. An object will accelerate if force is applied to it. The acceleration will happen in the
direction of the force. The acceleration will be less as the object gets bigger.
3. For every action there is always an equal and opposite reaction.
Putting these laws together, Newton was able to state the Law of Universal Gravitation: the
gravitational pull between two objects decreases as the objects get farther apart.
Newton’s Universe was a powerful idea because it said that all objects move according to
rational principles.
UNIT 2 —THE BIG BANG TEXT READER
37
Everything, from apples to planets, obeys the same unchanging laws. By combining physics,
mathematics, and astronomy, Newton made a giant leap in human understanding of Earth
and the cosmos.
Calculus
Newton came up with a new mathematical system for dealing with changing quantities. It is
now called calculus. Newton didn’t publish his method. He used it to solve problems.
Later, German scientist Gottfried Wilhelm von Leibniz also worked out “the calculus.” His
system was easier to use.
Newton accused Leibniz of stealing his ideas. Historians now believe that each invented the
calculus on their own.
Newton was made a knight by Queen Anne in 1705. At his death in 1727, he was buried in
London’s Westminster Abbey.
Hubble
Looking through a telescope, Hubble proved that the Universe is expanding.
Edwin Hubble: Evidence for an Expanding Universe (1150L)
By Cynthia Stokes Brown
In the course of five years, Edwin Hubble twice changed our understanding of the Universe,
helping to lay the foundations for the Big Bang theory. First he demonstrated that the
Universe was much larger than previously thought, then he proved that the Universe is
expanding.
Early life and education
Edwin Powell Hubble was the son of an insurance executive who grew up outside Chicago.
He was more outstanding as an athlete than as a student, although he did earn good grades
in every subject (except spelling).
At the University of Chicago, Hubble studied mathematics, astronomy, and philosophy —
and played for the school’s basketball team. He graduated with a bachelor of science in
1910, and then spent 1911 to 1914 earning his master’s as one of Oxford University’s first
Rhodes scholars. Though he studied law and Spanish there, his love of astronomy never
diminished.
At Yerkes Observatory
Moving back to the United States, Hubble enrolled as a graduate student at the University of
Chicago and studied the stars at their Yerkes Observatory in Wisconsin. It was here that he
began to study the faint nebulae that would be the key to his greatest discoveries. After
UNIT 2 —THE BIG BANG TEXT READER
38
receiving his doctorate in astronomy from the University of Chicago in 1917, he won an offer
to join the staff at the prestigious Mount Wilson Observatory, near Pasadena, California.
At Mount Wilson Observatory
Arriving at Mount Wilson in 1919, he joined an astronomy establishment that was just
beginning to grasp cosmic distances. The key to that effort was work that had been done
studying Cepheid variable stars, roughly a decade earlier, by Henrietta Swan Leavitt at
Harvard. These stars brighten and dim in a predictable pattern, and their distance from us
can be worked out by measuring how bright they appear to us.
Another astronomer at the observatory, Harlow Shapley, built on Leavitt’s findings and
shocked the world with his conclusions about the size of the Milky Way. Using the Cepheid
variables, Shapley judged that the Milky Way was 300,000 light years across — 10 times
bigger than previously thought.
Hubble began his work at Mount Wilson just as the new 2.56-meter Hooker Telescope, the
most powerful on Earth, was completed. With it, he was able to peer into the sky with greater
detail than anyone had previously. After years of observation, Hubble made an extraordinary
discovery. In 1923 he spotted a Cepheid variable star in what was known as the Andromeda
Nebula. Using Leavitt’s techniques, he was able to show that Andromeda was nearly 1
million light years away and clearly a galaxy in its own right, not a gas cloud.
Hubble then went on to discover Cepheids in multiple nebulae, and proved, in a 1924 paper
called “Cepheids in Spiral Nebula,” that galaxies existed outside our own. Overnight, he
became the most famous astronomer in the world, and people everywhere had to get used
to the fact that the Universe was far vaster than anyone had imagined. Shapley, for one, was
shaken by the news. He wrote Hubble, “I do not know whether I am sorry or glad to see this
break in the nebular problem. Perhaps both.”
In 1926, while developing a classification system for galaxies, Hubble discovered an odd
fact: Almost every galaxy he observed appeared to be moving away from the Earth. He
knew this because the light coming from the galaxies exhibited redshift. Light waves from
distant galaxies get stretched by the expansion of the Universe on their way to Earth. This
shifts visible light toward the red end of the spectrum.
Building on the work of Vesto Slipher, who measured the redshifts associated with galaxies
more than a decade earlier, Hubble and his assistant, Milton Humason, discovered a rough
proportionality between the distances and redshifts of 46 galaxies they studied. By 1929
they had formulated what became known as Hubble’s Law. Hubble’s Law basically states
that the greater the distance of a galaxy from ours, the faster it recedes. It was proof that the
Universe is expanding.
It was also the first observational support for a new theory on the origin of the Universe
proposed by Georges Lemaitre: the Big Bang. After all, an expanding Universe must once
have been smaller.
UNIT 2 —THE BIG BANG TEXT READER
39
Later life
Hubble achieved scientific superstardom for his discoveries and is still considered a brilliant
observational astronomer. He ran the Mount Wilson Observatory for the rest of his life,
popularized astronomy through books and lectures, and worked to have astronomy
recognized by the Nobel Prize committee.
He also played a pivotal role in the design and construction of the Hale Telescope, on
Palomar Mountain, California. At 5.08 meters, the Hale was four times as powerful as the
Hooker Telescope and existed as the most advanced telescope on Earth for some time.
After its completion in 1948, Edwin Hubble was given the honor of first use. When asked by
a reporter what he expected to find, Hubble answered: “We hope to find something we
hadn’t expected.”
Edwin Hubble: Evidence for an Expanding Universe (1000L)
By Cynthia Stokes Brown, adapted by Newsela
In the course of five years, Edwin Hubble made two major discoveries that changed our
understanding of the Universe. He demonstrated that the Universe was much larger than
previously thought. He also proved that the Universe is expanding.
His discoveries helped to support the Big Bang theory.
Early life and education
Edwin Hubble was born on November 20, 1889, and grew up outside Chicago. He was a
better athlete than a student, although he did earn good grades in every subject, except
spelling.
At the University of Chicago, Hubble studied mathematics, astronomy, and philosophy —
and played for the school’s basketball team.
He graduated with a bachelor of science in 1910, and then spent 1911 to 1914 earning his
master’s degree at Oxford University. Though he studied law and Spanish there, his love of
astronomy never diminished.
At Yerkes Observatory
Hubble moved back to the U.S. and enrolled as a graduate student at the University of
Chicago. He studied the stars at its Yerkes Observatory in Wisconsin.
It was here that he began to study the distant nebulae that would be the key to his greatest
discoveries. A nebula is a cloud of dust and gasses in outer space. The plural of nebula is
nebulae.
After receiving his doctorate in astronomy from the University of Chicago in 1917, he joined
the staff at the prestigious Mount Wilson Observatory, near Pasadena, California.
UNIT 2 —THE BIG BANG TEXT READER
40
Major discoveries at Mount Wilson Observatory
When Hubble arrived at Mount Wilson in 1919, astronomers around the world were trying to
grasp cosmic distances.
Scientists measured the immense distances using Cepheid variable stars. These stars
brighten and dim in a predictable pattern, and their distance from us can be worked out by
measuring how bright they appear to us. An astronomer at the observatory used Cepheid
stars to determine that the Milky Way was 300,000 light years across — 10 times bigger
than previously thought.
Hubble began his work at Mount Wilson just as the new 2.56-meter Hooker Telescope, the
most powerful on Earth, was completed. With it, he was able to peer into the sky with greater
detail than anyone had previously.
After years of observation, Hubble made an extraordinary discovery. In 1923, he spotted a
Cepheid star in what was known as the Andromeda Nebula. He was able to show that
Andromeda was nearly 1 million light years away and clearly a galaxy in its own right, not a
gas cloud.
Hubble then went on to discover Cepheids in multiple nebulae, and proved that galaxies
existed outside our own. Overnight, he became the most famous astronomer in the world,
and people everywhere had to get used to the fact that the Universe was far vaster than
anyone had imagined.
In 1926, Hubble discovered an odd fact: Almost every galaxy he observed appeared to be
moving away from the Earth. He knew this because the light coming from the galaxies
exhibited redshift. Light waves from distant galaxies get stretched by the expansion of the
Universe on their way to Earth. This shifts visible light toward the red end of the spectrum.
Hubble and his assistant, Milton Humason, discovered a relationship between the distances
and redshifts of 46 galaxies they studied. By 1929, they had formulated what became known
as Hubble’s Law. Hubble’s Law basically states that the greater the distance of a galaxy
from ours, the faster it recedes. It was proof that the Universe is expanding.
It was also the first observational support for a new theory on the origin of the Universe
proposed by Georges Lemaitre: the Big Bang. After all, an expanding Universe must once
have been smaller.
His later life
Hubble achieved scientific superstardom for his discoveries. He is still considered a brilliant
observational astronomer. He ran the Mount Wilson Observatory for the rest of his life, and
popularized astronomy through books and lectures.
He also worked to have astronomy recognized by the Nobel Prize committee.
Hubble made important contributions to the design and construction of the Hale Telescope,
on Palomar Mountain in California. At 5.08 meters, the Hale was four times as powerful as
the Hooker Telescope and was the most advanced telescope on Earth for some time. After
its completion in 1948, Edwin Hubble was given the honor of first use. When asked by a
UNIT 2 —THE BIG BANG TEXT READER
41
reporter what he expected to find, Hubble answered: “We hope to find something we hadn’t
expected.” He died in 1953 in San Marino, California.
Edwin Hubble: Evidence for an Expanding Universe (850L)
By Cynthia Stokes Brown, adapted by Newsela
American astronomer Edwin Hubble made two major discoveries that changed our
understanding of the Universe. He showed that the Universe is much larger than previously
thought. He also proved that the Universe is expanding.
His discoveries helped to support the Big Bang theory.
Early life and education
Edwin Hubble was born on November 20, 1889, and grew up outside Chicago. He was a
better athlete than a student; although he did earn good grades in every subject, except
spelling.
At the University of Chicago, Hubble studied mathematics, astronomy, and philosophy. He
also played for the school’s basketball team.
He graduated in 1910, and then went to England to earn his master’s degree at Oxford
University. Though he studied law and Spanish there, his never lost his love of astronomy.
At Yerkes Observatory
Hubble moved back to the U.S. and enrolled as a graduate student at the University of
Chicago. He studied the stars at its Yerkes Observatory in Wisconsin.
It was here that he began to study the distant nebulae that would be the key to his greatest
discoveries. A nebula is a cloud of dust and gasses in outer space. The plural of nebula is
nebulae.
Hubble received his doctorate in astronomy from the University of Chicago in 1917. He then
joined the staff at the respected Mount Wilson Observatory, near Pasadena, California.
Major discoveries at Mount Wilson Observatory
When Hubble arrived at Mount Wilson in 1919, astronomers were trying to measure the
huge distances in space.
Scientists measured the massive distances using Cepheid variable stars. These stars
brighten and dim in a predictable pattern. Their distance from us can be worked out by
measuring how bright they appear to us.
An astronomer at the observatory used Cepheid stars to determine that the Milky Way was
300,000 light years across. That was 10 times bigger than people previously thought.
UNIT 2 —THE BIG BANG TEXT READER
42
Hubble began his work at Mount Wilson just as the new 2.56-meter Hooker Telescope was
completed. This telescope was the most powerful on Earth. With it, he was able to look into
the sky with greater detail than anyone had before.
After years of observation, Hubble made an extraordinary discovery. In 1923, he spotted a
Cepheid star in what was known as the Andromeda Nebula. He showed that Andromeda
was nearly 1 million light years away and clearly a galaxy in its own right, not a gas cloud.
Hubble then went on to prove that galaxies existed outside our own. Overnight, he became
the most famous astronomer in the world. People everywhere had to get used to the fact
that the Universe was much larger than anyone had imagined.
In 1926, Hubble discovered an odd fact: Almost every galaxy he observed appeared to be
moving away from the Earth.
He knew this because the light coming from the galaxies exhibited redshift. Light waves from
distant galaxies get stretched by the expansion of the Universe on their way to Earth. This
shifts visible light toward the red end of the spectrum.
Hubble and his assistant discovered a relationship between the distances and redshifts of 46
galaxies they studied. By 1929, they had written what became known as Hubble’s Law.
Hubble’s Law basically states that the greater the distance of a galaxy from ours, the faster it
moves away from us. It was proof that the Universe is expanding.
It was also the first observational support for a new theory on the origin of the Universe
proposed by Georges Lemaitre: the Big Bang. After all, an expanding Universe must once
have been smaller.
His later life
Hubble achieved scientific superstardom for his discoveries. He is still considered a brilliant
observational astronomer. For the remainder of his life, he ran the Mount Wilson
Observatory and popularized astronomy through books and lectures.
He also worked to have astronomy recognized by the Nobel Prize committee.
Hubble contributed greatly to the design and construction of the Hale Telescope, on Palomar
Mountain in California. At 5.08 meters, the Hale was four times as powerful as the Hooker
Telescope and was the most advanced telescope on Earth for some time.
After its completion in 1948, Edwin Hubble was given the honor of first use. When asked by
a reporter what he expected to find, Hubble answered: “We hope to find something we
hadn’t expected.” He died in 1953 in San Marino, California.
Edwin Hubble: Evidence for an Expanding Universe (720L)
By Cynthia Stokes Brown, adapted by Newsela
UNIT 2 —THE BIG BANG TEXT READER
43
Edwin Hubble was an American astronomer who made two major discoveries. Hubble
showed that the Universe is much larger than anyone thought. He also proved that the
Universe is expanding. Both changed the way we understand the Universe.
His discoveries helped to support the Big Bang theory.
Early life and education
Edwin Hubble was born on November 20, 1889, and grew up outside Chicago. When he
was young, he was a better athlete than a student. He did earn good grades in every
subject, except spelling.
At the University of Chicago, Hubble studied mathematics, astronomy, and philosophy. He
also played for the school’s basketball team.
After he graduated, he went to England to get his master’s degree. He studied law and
Spanish there, but he never lost his love of astronomy.
At Yerkes Observatory
Hubble moved back to the United States and enrolled at the University of Chicago. He
studied the stars at the Yerkes Observatory in Wisconsin.
It was here that Hubble began to study nebulae. A nebula is a cloud of dust and gasses in
outer space. The plural of nebula is nebulae. Far-away nebulae were the key to his greatest
discoveries.
Hubble got his Ph.D. in astronomy from the University of Chicago in 1917. He then joined
the staff at the famous Mount Wilson Observatory in California.
Major discoveries at Mount Wilson Observatory
Hubble arrived at Mount Wilson in 1919. At that time, astronomers were trying to measure
the huge distances in space.
Scientists measured these massive distances using Cepheid variable stars. Cepheid stars
brighten and dim in a pattern. If we measure how bright they are, we can figure out how far
away they are.
The Mount Wilson Observatory was using a new telescope when Hubble started work. The
2.56-meter Hooker Telescope was the most powerful on Earth. Hubble used it to see the sky
in greater detail than anyone had before.
Hubble made an extraordinary discovery in 1923. He used Cepheid stars to show that one
nebula was one million light years away.
He also proved that other galaxies exist outside our own. He became the most famous
astronomer in the world.
People now had to accept that the Universe was much larger than anyone had imagined.
UNIT 2 —THE BIG BANG TEXT READER
44
In 1926, Hubble discovered an odd fact. Almost every galaxy he observed appeared to be
moving away from the Earth. The light coming from these galaxies showed “redshift.” As
light travels to Earth from distant galaxies, it gets stretched by the expansion of the
Universe. This makes it appear red.
After studying 46 galaxies, Hubble and his assistant wrote Hubble’s Law. It states that the
farther a galaxy is from us, the faster it moves away from us. It was proof that the Universe
is expanding.
It also supported the new Big Bang theory. After all, an expanding Universe must once have
been smaller.
His later life
Hubble became a scientific superstar for his discoveries. He is still remembered as a brilliant
astronomer.
He ran the Mount Wilson Observatory for the rest of his life. His books and lectures helped
make astronomy more popular among the public. He also worked to make astronomers able
to win the Nobel Prize.
Hubble helped design the Hale Telescope in California. It was the most advanced telescope
on Earth for some time.
After its completion in 1948, Hubble was allowed to use it first. When asked by a reporter
what he expected to find, Hubble answered: “We hope to find something we hadn’t
expected.” He died in 1953 in San Marino, California.
UNIT 2 —THE BIG BANG TEXT READER
45
Approaches to Knowledge
How do people create knowledge? It starts by being puzzled, curious, or even confused
about the world. There's a sense of wonder in it all.
Approaches to Knowledge (960L)
By Bob Bain
Here in a library, surrounded by books, I’ve set out to write about knowledge. Libraries make
such appropriate places to discuss knowledge because their purpose is to store knowledge
— that’s why communities build them. In many ways, libraries are repositories of collective
learning, an idea that is very important in the Big History course.
In this library and others, knowledge exists in many forms: books, maps, films, videos, CDs,
and, of course, textbooks.
The Big History class does not have a textbook, but it’s still useful to think about them and
the knowledge within.
I’ll tell you how I approached textbooks when I was in school and how most of my high
school and college students approach their textbooks.
They typically ask one big question: “How do we get the stuff out of that textbook and into
our heads or, more important, onto the tests?” And frankly, that was the question I asked as
a student: “How can I get the facts out of the textbook and onto the test?”
Big History asks questions about knowledge
In Big History, we ask a very different question: “How did that knowledge get into the
textbook?” How did people discover the facts or create the ideas that are in our textbooks or
in our courses?
Did you ever wonder how people create knowledge? Well, in this course you are going to
meet many people who discovered or created the information that is in your textbooks. You
will meet cosmologists, physicists, geologists, biologists, historians, and more. They are
excited to tell you what they have learned. But they are also excited to tell you how they
learned it. They are going to tell you how people in their field approach knowledge, the
questions that interest them, and how they used intuition, authority, logic, and evidence to
support their claims.
In Big History, we want you to pay attention to the questions these scientists and scholars
ask and the tools and evidence they use to answer their questions.
UNIT 2 —THE BIG BANG TEXT READER
46
Questions, tools, and evidence
Let’s look more carefully at how scholars use questions, tools, and evidence to create or
discover ideas, facts, and knowledge.
Most of the scholars you’ll meet in this course begin their investigations with questions. They
are puzzled, curious, or even baffled about the world around them. Sometimes their inquiry
begins in wonder.
Unlike textbooks that place questions at the end of learning, scholars pose the questions
first and use them to drive forward their learning.
Have you noticed that your teacher, the Big History units, and David Christian’s videos all
use questions — big questions — to launch your study?
Before conducting an inquiry, scholars speculate or make a thoughtful guess about what
they’ll learn. We often call these thoughtful guesses “conjectures” or “hypotheses.” But a
question or a hypothesis isn’t knowledge yet. Scholars need to gather information to answer
their questions. As you’ll learn in later units, sometimes people create or use new tools to
help them gather new information. For example, Galileo used a telescope he made to collect
new data about the heavens and the planets.
Scholars turn information into evidence to support claims
Gathering information does not automatically answer scholars’ questions. The information
must also be organized, analyzed, and then evaluated to see if it answers the initial or
driving questions.
Scholars may then make claims that answer their questions, and use the information as
evidence to support their claims. The stronger the evidence, the better the support for the
claim — and the greater chance it has to enter a textbook, for others to learn about it.
Scholars must show how they answered their questions
Let’s review. In this essay, I wondered how knowledge gets in textbooks and, in answer to
my question, I have described a few steps:






First, scholars have questions or they are curious or puzzled about something.
Second, they make a conjecture — a thoughtful guess or hypothesis.
Next, they gather information to answer the question, often using new tools in the
process.
They then analyze the information, think about it, and, perhaps, use some of it to
answer their question.
Scholars use information as evidence to support or make their claims.
When claims become well supported, they enter textbooks for students to learn.
But the scholars’ work is still not finished. They also must share what they learned and show
how they learned it. Why do they have to show how they learned it? Isn’t simply telling what
they learned enough? Why must they also explain how they conducted their investigation,
how they analyzed their information, and how they supported their claims?
UNIT 2 —THE BIG BANG TEXT READER
47
Scholars want to contribute to collective learning. They want people to see how they arrived
at their claims and what evidence supports the claims.
They do not want people to simply trust their claims based only on intuition, logic, or
authority.
Scholars also want others to improve their claims. This might involve using new tools or new
methods to gather new evidence to support or challenge the claims. Or it might mean asking
a different question entirely.
Different approaches to knowledge
All scholars ask important questions whether they are archaeologists, anthropologists,
biologists, or experts in another field. They all make conjectures, gather data, and analyze it
to make claims, but there are differences among and between these individuals. While they
all ask important questions, make conjectures, gather data, and analyze it to make claims,
there are differences among and between these scholars. They all begin asking questions,
but they ask different questions. They all have ways to gather data, but they often have
different ways to gather data.
As you meet the instructors in this course, do more than just learn what they are teaching;
try as well to understand how they do their work, what questions they ask, and how they
answer their questions. You might ask each of them:








What are the big questions that have interested you and driven you to personally
pursue the answers?
What were your guesses, speculations, and hypotheses?
How did you collect your evidence?
Where did you see the patterns in your evidence? What did those patterns seem to
indicate?
What were your biggest ideas?
How did you make your ideas public?
Why should others believe your ideas?
When and why have you changed your mind?
Make sure to pay attention to big questions that haven’t been answered. These are
questions that you and your friends might take up. Who knows? Maybe you can contribute to
the textbooks of the future.
Big History’s approach to knowledge
As you might have already guessed, in Big History we ask lots of big questions. We’re going
to ask questions about the physical world, the living world, and the human world. This will
require us to use many different approaches to knowledge. One of the most exciting things
about Big History is that we will use ideas that come from many different places. That is why
you’re going to meet such a great variety of people who have contributed to our collective
learning.
UNIT 2 —THE BIG BANG TEXT READER
48
And why we want to give you the chance to ask, “How did that knowledge get into the
textbook?”
Approaches to Knowledge (800L)
By Bob Bain, adapted by Newsela
I’m writing about knowledge here in a library, surrounded by books. A library is a good place
to discuss knowledge because its purpose is to store knowledge. That’s why communities
build them. Libraries are basically collections of collective learning. Collective learning is an
idea that is very important in the Big History course.
In this library and others, knowledge exists in many forms: books, maps, films, videos, CDs,
and, of course, textbooks.
The Big History class does not have a textbook. But it’s still useful to think about textbooks
and the knowledge they contain.
Most of my high school and college students ask just one big question about their textbooks.
“How can I get the facts out of the textbook and onto the test?” That was the same question I
asked when I was a student.
Big History asks questions about knowledge
In Big History, we ask a very different question: “How did that knowledge get into the
textbook?” How did people discover the facts or create the ideas that are in our textbooks?
Did you ever wonder how people create knowledge? Well, in this course you are going to
meet many people who discovered or created the information that is in your textbooks. You
will meet cosmologists, physicists, geologists, biologists, historians and more.
They are excited to tell you what they have learned. But they are also excited to tell you how
they learned it. They are going to tell you how people in their field approach knowledge and
the questions that interest them. They’ll also share with you how they used intuition,
authority, logic, and evidence to support their claims.
In Big History we want you to pay attention to the questions these scientists and scholars
ask. Also, pay attention to the tools and evidence they use to answer their questions.
Questions, tools, and evidence
How do scholars create or discover ideas, facts and knowledge? They use questions, tools,
and evidence.
Most of the scholars you’ll meet in this course begin their investigations with questions. They
are puzzled, curious, or even confused about the world around them.
Unlike textbooks that place questions at the end of learning, scholars ask the questions first.
They use the questions to drive their learning forward.
Have you noticed that the Big History course uses big questions to launch your study?
UNIT 2 —THE BIG BANG TEXT READER
49
Before investigating a question, scholars make a thoughtful guess about what they’ll learn.
We often call these thoughtful guesses “conjectures” or “hypotheses.” But a question or a
hypothesis isn’t knowledge yet. Scholars need to gather information to answer their
questions. As you’ll learn in later units, sometimes people create or use new tools to help
them gather new information. For example, Galileo made his own telescope to collect new
data about the heavens and the planets.
Scholars turn information into evidence to support claims
Gathering information does not automatically answer scholars’ questions. The information
must also be organized and analyzed. It must be evaluated to see if it answers the driving
questions that were asked at the beginning.
Scholars may then make claims that answer their questions, and use the information as
evidence to support their claims. The stronger the evidence, the better the support for the
claim. A better-supported claim is more likely to enter a textbook, for others to learn about it.
Scholars must show how they answered their questions
Let’s review. In this essay, I wondered how knowledge gets in textbooks and, in answer to
my question, I described a few steps:






First, scholars have a question or they are curious or puzzled about something.
Second, they make a conjecture — a thoughtful guess or hypothesis.
Next, they gather information to answer the question, often using new tools.
They then analyze the information, think about it, and perhaps use some of it to
answer their question.
Scholars use information as evidence to support their claims.
When claims become well supported, they enter textbooks for students to learn.
But the scholars’ work is still not finished. They must also show how they learned this new
information. Why do they have to show how they learned it? Isn’t simply telling what they
learned enough? Why must they also explain how they conducted their investigation, how
they analyzed their information, and how they supported their claims?
Scholars want to contribute to collective learning. They want people to see how they arrived
at their claims and what evidence supports the claims.
They do not want people to simply trust their claims based only on intuition, logic, or
authority.
Scholars also want others to improve their claims. This might mean using new tools or new
methods to gather new evidence to support or challenge the claims. Or it might mean asking
a different question entirely.
Different approaches to knowledge
All scholars ask important questions whether they are archaeologists, anthropologists,
biologists, or other scientists. They all begin asking questions, but they ask different
UNIT 2 —THE BIG BANG TEXT READER
50
questions. They all have ways to gather data, but they often have different ways to gather
data.
As you meet the instructors in this course, do more than just learn what they are teaching.
Try to understand how they do their work, what questions they ask, and how they answer
their questions. You might ask each of them:








What are the big questions that have interested you and driven you to personally
search for the answers?
What were your guesses, speculations, and hypotheses?
How did you collect your evidence?
Where did you see the patterns in your evidence? What did those patterns seem to
show?
What were your biggest ideas?
How did you make your ideas public?
Why should others believe your ideas?
When and why have you changed your mind?
Make sure to pay attention to big questions that haven’t been answered. These are
questions that you and your friends might take up. Who knows? Maybe you can add to the
textbooks of the future.
Big History’s approach to knowledge
In Big History we ask lots of big questions. We’re going to ask questions about the physical
world, the living world, and the human world. We will need to use many different approaches
to knowledge. One of the most exciting things about Big History is that we will use ideas that
come from many different places. That is why you’re going to meet many different people
who have contributed to our collective learning.
We want you to ask, “How did that knowledge get into the textbook?”
Approaches to Knowledge (700L)
By Bob Bain, adapted by Newsela
I’m writing about knowledge here in a library. I’m surrounded by books. A library is a good
place to write about knowledge. Libraries hold our collective learning. That is why
communities build them. The idea of collective learning is very important in the Big History
course.
Libraries hold knowledge of many kinds: books, maps, movies, CDs, and of course,
textbooks.
The Big History class does not have a textbook. But it’s still useful to think about textbooks
and the knowledge they contain.
UNIT 2 —THE BIG BANG TEXT READER
51
Most of my students ask just one big question about their textbooks. “How can I get the facts
out of the textbook and onto the test?” That was the same question I asked when I was a
student.
Big History asks questions about knowledge
In Big History, we ask a very different question: “How did that knowledge get into the
textbook?” We want to find out how people came up with the facts or ideas that are in our
textbooks.
Did you ever wonder how people create knowledge? In this course you will meet many
scientists who created the information that is in your textbooks.
They are excited to tell you what they have learned. But they are also excited to tell you how
they learned it.
In Big History we want you to pay attention to the questions these scientists ask. Also, pay
attention to the tools and evidence they use to answer their questions.
Questions, tools, and evidence
How do scholars create or discover ideas, facts and knowledge? They use questions, tools
and evidence. Most begin their investigations with questions. They are curious about the
world around them.
Textbooks place questions at the end of learning. Scholars ask the questions first. They use
questions to drive their learning forward.
Have you noticed that the Big History course uses big questions to begin your study?
Before investigating a question, scholars make a thoughtful guess about what they’ll learn.
We call these thoughtful guesses “conjectures” or “hypotheses.” Scholars need to gather
information to answer their questions. Sometimes people create or use new tools to help
them gather new information. For example, Galileo made a telescope to collect new data
about the planets.
Scholars turn information into evidence to support claims
Once scholars gather information, their job is just beginning. They must organize the
information and analyze it. They must see if it answers their questions. Scholars may then
make claims that answer their questions. They use the information as evidence to support
their claims. With strong evidence, a claim may enter a textbook, where others can learn
about it.
Scholars must show how they answered their questions
Let’s review. In this essay, I wondered how knowledge gets in textbooks. In answer to my
question, I described a few steps:


First, scholars have a question or they are curious or puzzled about something.
Second, they make a thoughtful guess.
UNIT 2 —THE BIG BANG TEXT READER
52




Next, they gather information to answer the question, often using new tools.
They then study the information, think about it, and perhaps use some of it to answer
their question.
Scholars use information as evidence to support their claims.
When claims become well supported, they enter textbooks for students to learn.
But scholars must also show how they learned this new information. They must explain what
questions they asked, how they answered them, what information they gathered.
Scholars want to add to our collective learning. They want people to see how they arrived at
their claims and what evidence supports the claims. They do not want people to trust them
just because they are scholars or scientists.
Scholars also want others to improve their claims. This might mean using new tools to
gather new evidence. It might mean asking a different question entirely.
Different approaches to knowledge
All scholars ask important questions, from archaeologists to zoologists. They all begin
asking questions, but they ask different questions. They all gather data, but they gather data
differently.
As you meet the instructors in this course, don’t just learn what they are teaching. Try to
understand how they do their work. What questions do they ask? How do they answer
them?
You might ask them:








What are the big questions that have interested you?
What were your guesses, speculations, and hypotheses?
How did you collect your evidence?
Where did you see the patterns in your evidence? What did those patterns seem to
show?
What were your biggest ideas?
How did you make your ideas public?
Why should others believe your ideas?
When and why have you changed your mind?
Make sure to pay attention to big questions that haven’t been answered. These are
questions that you and your friends might take up. Who knows? Maybe you can add to the
textbooks of the future.
Big History’s approach to knowledge
In Big History we ask lots of big questions. We’re going to ask questions about the physical
world, the living world, and the human world. We will need to use many different approaches
to knowledge.
UNIT 2 —THE BIG BANG TEXT READER
53
The ideas we use will come from many different places. You will meet many different people
who contributed to our collective learning. In the end, we want you to ask, “How did that
knowledge get into the textbook?”
UNIT 2 —THE BIG BANG TEXT READER
54
Structure of Scientific Revolutions
In his famous book, Kuhn argued that science does not advance in a steady march, but
rather discoveries come in sudden bursts of progress.
In Their Own Words: Thomas Kuhn's The Structure of Scientific
Revolutions (1350L)
By Big History Project
Thomas Kuhn (1922–1996) was an American historian and philosopher of science who
began his career in theoretical physics before switching career paths. His book The
Structure of Scientific Revolutions, which was first published in 1962, is one of the most cited
academic books of all time and made Kuhn perhaps the most influential philosopher of
science in the twentieth century. His work challenged the prevailing view of progress in
“normal science,” which was that science has been a continuous increase in a set of
accepted facts and theories. He argued that, instead, the history of science has been
episodic, with periods of continuity interrupted by revolutionary science during which a new
“paradigm” changes the rules and direction of scientific research. His analysis of science,
which called into question its objectivity, caused a firestorm of controversy and continues to
inspire reaction and debate in and beyond scientific communities. Read these excerpts from
Kuhn's book, and consider the questions that follow each section.
I. A role for science
Normal science, the activity in which most scientists inevitably spend almost all their time, is
predicated on the assumption that the scientific community knows what the world is like.
Much of the success of the enterprise derives from the community’s willingness to defend
that assumption, if necessary at considerable cost. Normal science, for example, often
suppresses fundamental novelties because they are necessarily subversive of its basic
commitments. Nevertheless, so long as those commitments retain an element of the
arbitrary, the very nature of normal research ensures that novelty shall not be suppressed
for very long. Sometimes a normal problem, one that ought to be solvable by known rules
and procedures, resists the reiterated onslaught of the ablest members of the group within
whose competence it falls. On other occasions a piece of equipment designed and
constructed for the purpose of normal research fails to perform in the anticipated manner,
revealing an anomaly that cannot, despite repeated effort, be aligned with professional
expectation. In these and other ways besides, normal science repeatedly goes astray. And
when it does — when, that is, the profession can no longer evade anomalies that subvert the
existing tradition of scientific practice — then begin the extraordinary investigations that lead
the profession at last to a new set of commitments, a new basis for the practice of science.
The extraordinary episodes in which that shift of professional commitments occurs are the
UNIT 2 —THE BIG BANG TEXT READER
55
ones known in this essay as scientific revolutions. They are the tradition-shattering
complements to the tradition-bound activity of normal science.
The most obvious examples of scientific revolutions are those famous episodes in scientific
development that have often been labeled revolutions before ... the major turning points in
scientific development associated with the names of Copernicus, Newton, Lavoisier, and
Einstein. More clearly than most other episodes in the history of at least the physical
sciences, these display what all scientific revolutions are about. Each of them necessitated
the community’s rejection of one time-honored scientific theory in favor of another
incompatible with it. Each produced a consequent shift in the problems available for
scientific scrutiny and in the standards by which the profession determined what should
count as an admissible problem or as a legitimate problem-solution. And each transformed
the scientific imagination in ways that we shall ultimately need to describe as a
transformation of the world within which scientific work was done. Such changes, together
with the controversies that almost always accompany them, are the defining characteristics
of scientific revolutions.
II. The route to normal science
In this essay, "normal science" means research firmly based upon one or more past
scientific achievements, achievements that some particular scientific community
acknowledges for a time as supplying the foundation for its further practice. Today such
achievements are recounted, though seldom in their original form, by science textbooks,
elementary and advanced. These textbooks expound the body of accepted theory, illustrate
many or all of its successful applications, and compare these applications with exemplary
observations and experiments. Before such books became popular early in the nineteenth
century (and until even more recently in the newly matured sciences), many of the famous
classics of science fulfilled a similar function. Aristotle’s Physica, Ptolemy’s Almagest,
Newton’s Principia and Opticks, Franklin’s Electricity, Lavoisier’s Chemistry, and
Lyell’s Geology — these and many other works served for a time implicitly to define the
legitimate problems and methods of a research field for succeeding generations of
practitioners. They were able to do so because they shared two essential characteristics.
Their achievement was sufficiently unprecedented to attract an enduring group of adherents
away from competing modes of scientific activity. Simultaneously, it was sufficiently openended to leave all sorts of problems for the redefined group of practitioners to resolve.
Achievements that share these two characteristics I shall henceforth refer to as "paradigms,"
a term that relates closely to "normal science." By choosing it, I mean to suggest that some
accepted examples of actual scientific practice — examples which include law, theory,
application, and instrumentation together — provide models from which spring particular
coherent traditions of scientific research. These are the traditions which the historian
describes under such rubrics as "Ptolemaic astronomy" (or "Copernican"), "Aristotelian
dynamics" (or "Newtonian"), … and so on. The study of paradigms, including many that are
far more specialized than those named illustratively above, is what mainly prepares the
student for membership in the particular scientific community with which he will later
practice. Because he there joins men who learned the bases of their field from the same
UNIT 2 —THE BIG BANG TEXT READER
56
concrete models, his subsequent practice will seldom evoke overt disagreement over
fundamentals. Men whose research is based on shared paradigms are committed to the
same rules and standards for scientific practice. That commitment and the apparent
consensus it produces are prerequisites for normal science, that is, for the genesis and
continuation of a particular research tradition.
History suggests that the road to a firm research consensus is extraordinarily arduous ...
History also suggests, however, some reasons for the difficulties encountered on that road.
In the absence of a paradigm or some candidate for paradigm, all of the facts that could
possibly pertain to the development of a given science are likely to seem equally relevant.
As a result, early fact-gathering is a far more nearly random activity than the one that
subsequent scientific development makes familiar. Furthermore, in the absence of a reason
for seeking some particular form of more recondite information, early fact-gathering is
usually restricted to the wealth of data that lie ready to hand … Because the … facts …
could not have been casually discovered, technology has often played a vital role in the
emergence of new sciences.
… No natural history can be interpreted in the absence of at least some implicit body of
intertwined theoretical and methodological belief that permits selection, evaluation, and
criticism. If that body of belief is not already implicit in the collection of facts — in which case
more than “mere facts” are at hand — it must be externally supplied … No wonder, then,
that in the early stages of the development of any science different men confronting the
same range of phenomena, but not usually all the same particular phenomena, describe and
interpret them in different ways. What is surprising, and perhaps also unique in its degree to
the fields we call science, is that such initial divergences should ever largely disappear.
… To be accepted as a paradigm, a theory must seem better than its competitors, but it
need not, and in fact never does, explain all the facts with which it can be confronted ...
… When, in the development of a natural science, an individual or group first produces a
synthesis able to attract most of the next generation’s practitioners, the older schools
gradually disappear. In part their disappearance is caused by their members’ conversion to
the new paradigm. But there are always some men who cling to one or another of the older
views, and they are simply read out of the profession, which thereafter ignores their work.
The new paradigm implies a new and more rigid definition of the field. Those unwilling or
unable to accommodate their work to it must proceed in isolation or attach themselves to
some other group. [I]t is sometimes just its reception of a paradigm that transforms a group
previously interested merely in the study of nature into a profession or, at least, a discipline
…
When the individual scientist can take a paradigm for granted, he need no longer, in his
major works, attempt to build his field anew, starting from first principles and justifying the
use of each concept introduced. That can be left to the writer of textbooks…
UNIT 2 —THE BIG BANG TEXT READER
57
In Their Own Words: Thomas Kuhn's The Structure of Scientific
Revolutions (1040L)
By Big History Project, adapted by Newsela
Thomas Kuhn (1922–1996) was an American historian and philosopher of science. He
began his career in theoretical physics before switching career paths. His book, The
Structure of Scientific Revolutions, which was first published in 1962, is one of the most cited
academic books of all time and made Kuhn perhaps the most influential philosopher of
science in the twentieth century.
People had previously thought of progress in “normal science” as a continuous increase in a
set of accepted facts and theories. Kuhn disagreed. He argued that the history of science
has come in sudden bursts. Sometimes discoveries build on each other, but sometimes
there is revolutionary science that interrupts the steady march of progress. In revolutionary
science, a new “paradigm,” or worldview, changes the rules and direction of scientific
research.
His analysis of science, which called into question its objectivity, caused a firestorm of
controversy. It continues to inspire reaction and debate in scientific communities and
beyond.
The following excerpts have been adapted from his book to provide a simplified view of
Kuhn's arguments. Consider the questions that follow each section.
I. A role for science
Normal science, what most scientists spend most of their time doing, assumes that the
scientific community knows what the world is like. The scientific community must defend this
assumption if it wants to be successful.
Normal science often holds back fundamental novelties because they go against the
accepted way of thinking. Still, as long as scientists are willing to be proved wrong, these
novelties will eventually come out.
Sometimes a normal problem, one that should be solvable by known rules and procedures,
cannot be solved by the experts. Other times, a piece of equipment made for doing normal
research gives results that don’t make sense to the experts.
In these and other ways, normal science repeatedly goes off track. Scientists have to face
anomalies, or unexpected results they can’t explain. This is when they may begin
extraordinary investigations that lead science to a new way of thinking, a new basis for the
practice of science.
These times, when science must accept new realities, are known in this essay as scientific
revolutions. They shatter tradition, whereas normal science is bound to tradition.
UNIT 2 —THE BIG BANG TEXT READER
58
The most obvious examples of scientific revolutions are those famous episodes in scientific
development that are already called revolutions. These include the major turning points in
science associated with Copernicus, Newton, Lavoisier, and Einstein.
These episodes display what all scientific revolutions are all about. Each of them caused the
community to reject one accepted scientific theory for another one that was incompatible
with it. Each brought a new set of questions for scientists to answer. Each brought new
problems and new ways to solve these problems. Finally, each transformed the scientific
imagination — transformed the world where scientific work was done.
These changes, and the controversies that go with them, are what define scientific
revolutions.
Questions





In this excerpt, Kuhn introduces the term “normal science,” which he later defines as
“research firmly based upon past scientific achievements … “
What are anomalies in science? What role do anomalies play in the development of
science?
How does Kuhn define “scientific revolutions”?
According to Kuhn, what features do scientific revolutions have in common?
What is a theory? How is it different from a hypothesis or conjecture? How are
theories related to “normal science”?
II. The route to normal science
In this essay, "normal science" means research firmly based on past scientific
achievements. These past achievements form the foundation for further study.
Today these achievements are described by science textbooks. These textbooks provide the
core of accepted theory. They give examples of successful uses of these achievements, and
compare these uses with observations and experiments.
Before such books became popular early in the nineteenth century, many of the famous
classics of science served a similar function. Aristotle’s Physica, Ptolemy's Almagest,
Newton’s Principia and Opticks, Franklin’s Electricity, Lavoisier's Chemistry, and
Lyell’s Geology — these and many other works defined the problems and methods of
research for future scientists. They were able to do so because they shared essential
characteristics:
First, the discoveries they presented had never before been seen. This attracted people
from all fields to study them more. Also, these discoveries were open-ended enough to leave
more questions for future researchers to answer.
I’ll call achievements that share these two characteristics “paradigms.” These paradigms
provide models that produce unified traditions of scientific research.
These are traditions that historians call “Copernican astronomy” or “Newtonian dynamics”
and so on. A beginning scientist must study all the paradigms in his or her field before
starting research. Scientists in a field rarely disagree over fundamentals, since they all have
UNIT 2 —THE BIG BANG TEXT READER
59
accepted the same paradigm. They share the same rules and standards. That agreement it
produces is necessary for normal science — for the creation and continuation of a research
tradition.
History suggests that the road to a firm research agreement is extraordinarily difficult.
History also suggests, however, some reasons for the difficulties encountered on that road.
Without a paradigm, or a possible paradigm, all the facts that may relate to a given science
all seem worth considering equally. In a new field of science, fact-gathering is more random
that in a well-developed one.
Furthermore, without a reason for seeking out more hard-to-find information, early factgathering tends to find the data that is convenient to find. Because the facts could not have
been casually discovered, technology has often played a vital role in the emergence of new
sciences.
We can’t study and interpret the natural world without a system of theories and methods that
permits selection, evaluation and criticism. If that system is not in place, we have just “facts.”
No wonder then, that in the early stages of any science different scientists seeing roughly
the same things describe and interpret them in different ways. What is surprising, and
maybe even unique in science, is that such differences should ever disappear.
To be accepted as a paradigm, a theory must seem better than its competitors. But a theory
never does explain all the facts it may face, nor does it have to.
When, in science, an individual or group produces a new system that attracts most of the
next-generation scientists, the older systems gradually disappear. In part, they disappear
because members accept the new paradigm.
But there are always some scientists who cling to older views, but they are often ignored by
the scientific community. The new paradigm gives a stricter definition of what is acceptable.
Those who don’t agree with it must work alone or attach themselves to some other group.
A paradigm can transform people merely studying nature into a profession.
When an individual scientist can take a paradigm for granted, she doesn’t have to explain
the basic system in her works. She can assume that other scientists know the basic
paradigm.
It is textbooks, then, that still have to explain things step by step, from the beginning.
Questions


Kuhn believes textbooks hide the historical processes that create scientific theory
because they only discuss the finished products. Think about the science textbooks
you use. Do you agree with Kuhn?
What function did the “famous classics of science” play in their field? Why were they
able to serve this function?
UNIT 2 —THE BIG BANG TEXT READER
60





“Paradigm” is a word that Kuhn helped to popularize. How does he define it? What
role do paradigms play in normal science? How are paradigms and normal science
different?
How is Kuhn using the term “facts”? How are facts different from theories? What role
do paradigms play in “fact-gathering”?
How do paradigms come to be “paradigms”?
How are paradigms and disciplines related? How do paradigms help shape a
discipline?
Textbooks might be considered products of collective learning at some particular
point in time. How does collective learning relate fit into Kuhn’s argument about
scientific revolutions?
In Their Own Words: Thomas Kuhn's The Structure of Scientific
Revolutions (920L)
By Big History Project, adapted by Newsela
Thomas Kuhn (1922–1996) was an American historian and philosopher of science. He
began his career in theoretical physics before switching career paths. His book, The
Structure of Scientific Revolutions, was first published in 1962. It is one of the most cited
scholarly books of all time and made Kuhn perhaps the most influential philosopher of
science in the twentieth century.
People often think of science as a steady increase in accepted facts and theories. This is
what Kuhn calls “normal science.” But Kuhn argued that this was not always how things
worked.
He said that sometimes discoveries build on each other, but sometimes there is a sudden
burst of revolutionary science. In revolutionary science, a new “paradigm” changes the rules
and direction of scientific research. A paradigm is a way of thinking about the world.
His analysis said that science was not always strictly fact-based, but could affected by
people's views. This caused a lot of controversy. His work continues to spark reaction and
debate among scientists and others.
The following selections have been adapted from his book to provide a simplified view of
Kuhn's arguments. Consider the questions that follow each section.
I. A role for science
Normal science is what most scientists do most of the time. Normal science assumes that
we know what the world is like. This is a necessary assumption.
Normal science often holds back new information that goes against the basic view of what
the world is like. Still, as long as scientists are willing to be proved wrong, this new
information will eventually come out.
UNIT 2 —THE BIG BANG TEXT READER
61
Sometimes a normal problem that should be solvable by normal procedures stumps the
experts. Other times, a piece of equipment made for normal research gives results that don’t
seem to make sense.
In these and other ways, normal science can go off track. Scientists must face anomalies —
results that are different from what is expected — that they can’t explain. This is when they
begin new investigations that lead scientists to a new way of thinking.
These are scientific revolutions. Science must accept new realities. These include the major
turning points in science associated with Copernicus, Newton, Lavoisier, and Einstein.
These episodes are great examples of scientific revolutions. Each of them caused the
community to reject one scientific theory for another. Each brought a new set of questions
for scientists to answer. Each brought new problems and new ways to solve these problems.
Finally, each transformed the scientific imagination. Each transformed the world where
scientific work was done.
These changes and the controversy they cause are what define scientific revolutions.
II. The route to normal science
In this essay, “normal science” means research firmly based on past scientific
achievements. These past achievements form the base for further study.
Today, these achievements are described in science textbooks. The textbooks provide the
core of accepted theory. They give examples of successful uses of the achievements, and
compare these uses with observations and experiments.
Before textbooks became popular, the famous classics of science served a similar purpose.
Aristotle’s Physica, Ptolemy’s Almagest, Newton’s Principia and Opticks,
Franklin’s Electricity, Lavoisier’s Chemistry, and Lyell’s Geology — these and many other
works defined the problems and methods of research for future scientists. They were able to
do so because they shared essential characteristics:
First, the discoveries they presented were completely new. This attracted people from all
fields to study them more. Also, these discoveries were open-ended enough to leave more
questions for future researchers to answer.
I’ll call achievements that share these two characteristics “paradigms.” These paradigms
provide models that produce traditions of scientific research.
These are traditions that historians call “Copernican astronomy” or “Newtonian dynamics,”
for example. A beginning scientist must study all the paradigms in her field before starting
research. Scientists in a field rarely disagree over fundamentals, since they all have
accepted the same paradigm. They share the same rules and standards. That agreement it
produces is necessary for normal science — for the creation and continuation of a research
tradition.
History shows that coming to such an agreement is quite difficult. History also shows some
reasons that it is so difficult.
UNIT 2 —THE BIG BANG TEXT READER
62
Without a paradigm, all facts that a scientists comes across seem worth considering equally.
Fact-gathering can seem random.
Furthermore, without a reason for seeking out more hard-to-find information, early factgathering tends to find the data that is convenient to find. Technology has often played a
very important role in the emergence of new sciences because it can uncover information
that is not convenient to find.
We can’t study and interpret the world without a system of theories and methods that
permits selection, evaluation and criticism. If that system is not in place, we have just “facts.”
It’s not surprising that in the early stages of any science, different scientists seeing roughly
the same things describe and interpret them in different ways. What is surprising, and
maybe even unique in science, is that such differences can disappear.
To be accepted as a paradigm, a theory must seem better than its competitors. But it doesn’t
have to, and never does, explain all the facts it may face.
When a new scientific paradigm arrives on the scene, the older systems gradually disappear
because members accept the new paradigm.
Scientists who cling to older views are often ignored by the rest of the community. The new
paradigm gives a stricter definition of what is acceptable. Those who don’t agree with it must
work alone or attach themselves to some other group.
When an individual scientist can take a paradigm for granted, she doesn’t have to explain
the basic system in her works. She can assume that other scientists know the basic
paradigm.
It is textbooks, then, that still have to explain things step by step, from the beginning.
In Their Own Words: Thomas Kuhn's The Structure of Scientific
Revolutions (780L)
By Big History Project, adapted by Newsela
Thomas Kuhn (1922–1996) was an American historian and philosopher of science. He was
a physicist before changing careers. He published The Structure of Scientific Revolutions in
1962. It made Kuhn one of the most influential science philosophers of the twentieth century.
People often think of science as a steady process, building on itself. Kuhn calls this “normal
science.” But he stresses that, sometimes, there is a revolution in science.
In revolutionary science a new paradigm, or worldview, changes the rules of scientific
research.
His book argued that science is not always objective. This caused a lot of controversy. His
work continues to cause debate among scientists and others.
The following selections have been adapted from his book. They give a simplified view of
Kuhn's arguments. Think about the questions that follow each section.
UNIT 2 —THE BIG BANG TEXT READER
63
I. A role for science
Normal science is what most scientists do most of the time. Normal science assumes that
we know what the world is like.
In normal science, if there is some new information that doesn’t fit into the system, it may be
held back. Still, as long as scientists are willing to be proved wrong, this new information will
come out at some point.
Sometimes a normal problem stumps the experts. Other times, a piece of equipment gives
results that don’t seem to make sense. In these and other ways, science can go off track.
These are anomalies, something that is different than what is expected. When scientists
can’t explain an anomaly, they begin new investigations. Those investigations can lead to a
new way of thinking in science.
These are scientific revolutions. Science must accept new realities. These include the major
turning points in science associated with Copernicus, Newton, Lavoisier, and Einstein.
These episodes are good examples of scientific revolutions. Each of them caused scientists
to reject one theory for another. Each brought a new set of questions for scientists to
answer. Each brought new problems and new ways to solve these problems. Finally, each
transformed the scientific imagination. Each transformed the world where scientific work was
done.
These changes and the controversy they cause are what define scientific revolutions.
II. The route to normal science
In this essay, “normal science” means research that is firmly based on past scientific
achievements.
Today, these achievements are described in science textbooks. Textbooks explain the
accepted theory and show how it is successful through observations and experiments.
Before textbooks became popular, the classic works served this purpose.
Ptolemy’s Almagest, Newton’s Principia and Opticks, Franklin’s Electricity, and
Lyell’s Geology — these works defined ways of thinking for future scientists. They were able
to do so because they shared some important things in common:
First, they presented new discoveries. This attracted new people to study them more.
Second, the new discoveries were open-ended. It meant there was still much more to
discover.
Achievements that share these two things in common I’ll call “paradigms.” These paradigms
produce traditions of scientific research.
These are traditions that historians call “Copernican astronomy” or “Newtonian dynamics,”
for example. A beginning scientist must study the paradigms in her field before starting
research.
UNIT 2 —THE BIG BANG TEXT READER
64
Scientists in a field rarely disagree over fundamentals, since they all have accepted the
same paradigm. They share the same rules and standards. The agreement it produces is
necessary for normal science — for the creation and continuation of a research tradition.
History shows that coming to such an agreement is quite difficult. History also shows some
reasons why it is so difficult.
In the early stages of a field of science, researchers seeing the same thing may describe
and interpret it in different ways. That's no surprise. What is surprising is that these
differences can disappear.
To be accepted as a paradigm, a theory must seem better than its competitors. But it doesn’t
have to, (and never does) explain all the facts it may face.
When a new scientific paradigm arrives, members of the community begin to accept it.
The older systems slowly disappear.
Scientists who stick with older views are often ignored by the rest of the community. The
new paradigm gives a stricter definition of what is acceptable. Scientists who don’t agree
with it must work alone or join another group.
When a scientist can take a paradigm for granted, she doesn’t have to explain the basic
system in her works. She can assume that other scientists know the basic paradigm.
It is textbooks, then, that still have to explain things step by step, from the beginning.
UNIT 2 —THE BIG BANG TEXT READER
65
Henrietta Leavitt
Leavitt was an important contributor to our understanding of the size of the Universe.
Henrietta Leavitt: Measuring Distance in the Universe (1300L)
By Cynthia Stokes Brown
Henrietta Leavitt discovered the relationship between the intrinsic brightness of a variable
star and the time it took to vary in brightness, making it possible for others to estimate the
distance of these faraway stars, conclude that additional galaxies exist, and begin mapping
the Universe.
Early life and education
Henrietta Swan Leavitt was a minister's daughter whose family moved frequently. When she
was about 14, the family moved to Cleveland, Ohio, and in 1885 Leavitt enrolled in Oberlin
College to prepare for the strict entrance requirements of the college she really wanted to
attend — the Society for Collegiate Instruction of Women, later known as Radcliffe College
(now part of Harvard University), in Cambridge, Massachusetts – a dream she achieved at
age 20. She discovered her calling in her senior year when she took a course in astronomy.
At the Harvard College Observatory
Leavitt liked astronomy so much that after graduation she became a volunteer at the
Harvard College Observatory as a “computer.” This was the name used for women who
examined tiny dots on time-exposed photographs of the night sky and then measured,
calculated, and recorded their observations in ledger books. Eventually, in 1902, Leavitt was
hired at 30 cents an hour; she continued to work at the observatory for the remaining 19
years of her life.
Leavitt took a special interest in the Magellanic Clouds, a pair of luminous hazes now known
to be irregular galaxies, the nearest ones to our Milky Way. At the time, no one knew what
the clouds were. Since the Magellanic Clouds are only visible in the southern hemisphere,
Leavitt could not see them directly. She could merely look at photographic plates taken at
Harvard’s auxiliary observatory, in Arequipa, Peru, and sent to Cambridge by ship around
the tip of South America.
Using Cepheid variables
One of Leavitt’s jobs was to examine the variable stars, which, unlike most stars, vary in
brightness because of fluctuations within themselves. In the course of her work, Leavitt
discovered 2,400 new variable stars, half the known ones in her day. A certain group of
variable stars, later called Cepheid variables, fluctuate in brightness (luminosity) in a regular
pattern called their “period.” This period ranges from about one day to nearly four months.
UNIT 2 —THE BIG BANG TEXT READER
66
By comparing thousands of photographic plates, Leavitt discovered a direct correlation
between the time it takes for a Cepheid variable to go from bright to dim and back to bright,
and how bright the star actually is (its “intrinsic brightness”). The longer the period of
fluctuation, the brighter the star. This meant that even though a star might appear extremely
dim, if it had a long period it must actually be extremely large; it appeared dim only because
it was extremely far away. By calculating how bright it appeared from Earth and comparing
this to its intrinsic brightness, one could estimate how much of the star’s light had been lost
while reaching Earth, and how far away the star actually was.
Leavitt published her first paper on the period-luminosity correlation in 1908. Four years after
that, she published a table of the periods of 25 Cepheid variables. Nine years later, in 1921,
she died of cancer at age 53 in Cambridge.
Leavitt's Legacy
Before Leavitt established the period-luminosity relationship, astronomers could determine
cosmic distances out only about 100 light years. Using her insights, astronomers were able
to estimate the Magellanic Clouds to be in the range of 100,000 light years from Earth —
much further than anyone had imagined — meaning they could not be within the Milky Way
galaxy.
The largest telescope then in existence opened in 1904 at Mount Wilson, near Los Angeles,
California. In 1919, the astronomer Edwin Hubble took a job there, after finishing his PhD in
astronomy at the University of Chicago. Using the Mount Wilson telescope and building on
Leavitt’s work, Hubble located Cepheid variables so far away that they conclusively
established the presence of other galaxies. By 1925, most astronomers agreed that our
galaxy is one among a multitude — a small outpost in a Universe full of galaxies.
Leavitt initially worked under a director of the Harvard College Observatory who did not
encourage theorizing but preferred only to accumulate data. A later director even tried to
take some of the credit for her work after her death. Now, however, Leavitt is recognized as
a key contributor to our understanding of the size of the Universe.
A modest life
Leavitt never married. She gradually became deaf, starting with an illness when she was a
young adult. She was buried in Cambridge in the family plot, near the graves of Henry and
William James. Her total estate was appraised at $314.91. In her obituary, a senior
colleague wrote: “[She] was possessed of a nature so full of sunshine that, to her, all of life
became beautified and full of meaning.”
Henrietta Leavitt: Measuring Distance in the Universe (980L)
By Cynthia Stokes Brown, adapted by Newsela
Henrietta Swan Leavitt studied distant stars that dim and brighten. These are called Cepheid
variable stars. She made it possible for others to measure huge cosmic distances, discover
additional galaxies, and begin mapping the universe.
UNIT 2 —THE BIG BANG TEXT READER
67
Leavitt was a minister's daughter. Her family moved frequently.
She attended the Society for Collegiate Instruction of Women, which is now part of Harvard
University. It was a school she had dreamed of attending. In her senior year she discovered
her calling — astronomy.
At the Harvard College Observatory
Leavitt liked astronomy so much that after graduation she became a volunteer at the
Harvard College Observatory as a “computer.” This was the name used for women who
examined tiny dots on photographs of the night sky. They then measured, calculated, and
recorded their observations in ledger books.
Eventually, Leavitt was hired at 30 cents an hour. She continued to work at the observatory
for the remaining 19 years of her life.
Leavitt was very interested in the Magellanic Clouds, two glowing hazes in space. At the
time, no one knew what the clouds were. Since the Magellanic Clouds are only visible in the
southern hemisphere, Leavitt could not see them directly. She could merely look at
photographic plates taken at Harvard’s observatory in Peru, and sent to Cambridge by ship
around the tip of South America.
Using Cepheid variables
One of Leavitt’s jobs was to examine the variable stars, which, unlike most stars, vary in
brightness because of changes within themselves. In the course of her work, Leavitt
discovered 2,400 new variable stars, half the known ones in her day.
A certain group of variable stars, later called Cepheid variables, fluctuate in brightness
(luminosity) in a regular pattern called their “period.” This period ranges from about one day
to nearly four months.
Leavitt studied thousands of photographs of these stars. She discovered a way to determine
how bright they are and how far away they are.
She found that the longer a star’s period, the brighter it was. By comparing how bright a star
appeared, and how bright it actually was, Leavitt could estimate how much of the star’s light
had been lost while reaching Earth, and how far away the star actually was.
Leavitt published her first paper on the period-luminosity relationship in 1908. Four years
after that she published a table of the periods of 25 Cepheid variables. Nine years later, in
1921, she died of cancer at age 53 in Cambridge, Massachusetts.
Leavitt's Legacy
Before Leavitt established the period-luminosity relationship, astronomers could only
measure cosmic distances up to about 100 light years. Using her insights, astronomers were
able to estimate the Magellanic Clouds to be about 100,000 light years from Earth — much
further than anyone had imagined — meaning they could not be within the Milky Way
galaxy.
UNIT 2 —THE BIG BANG TEXT READER
68
Edwin Hubble at the Mount Wilson Observatory near Los Angeles used a state-of-the-art
telescope to find Cepheid variable stars that were extremely far away. They were so far
away, they proved the existence of other galaxies.
By 1925, most astronomers agreed that our galaxy is just one of many.
Leavitt initially worked under a director of the Harvard College Observatory who did not
encourage theorizing but preferred only to accumulate data. A later director even tried to
take some of the credit for her work after her death. Now, however, Leavitt is recognized as
a key contributor to our understanding of the size of the Universe.
A modest life
Leavitt never married. She gradually became deaf, starting with an illness when she was a
young adult. She was buried in Cambridge in the family plot. Her total estate was appraised
at $314.91. In her obituary, a senior colleague wrote: “[She] was possessed of a nature so
full of sunshine that, to her, all of life became beautified and full of meaning.”
Henrietta Leavitt: Measuring Distance in the Universe (840L)
By Cynthia Stokes Brown, adapted by Newsela
Henrietta Swan Leavitt studied distant stars that dim and brighten. By studying how long it
takes for them to change brightness, she determined how bright they were and how far away
they were.
She made it possible for others to measure huge cosmic distances, discover additional
galaxies, and begin mapping the universe.
Leavitt was a minister's daughter. Her family moved frequently.
She went to the Society for Collegiate Instruction of Women (now part of Harvard
University). It was a school she had dreamed of attending. In her senior year, she
discovered her calling — astronomy.
At the Harvard College Observatory
Leavitt liked astronomy so much that after graduation she became a volunteer at the
Harvard College Observatory as a “computer.” This was the name used for women who
examined tiny dots on photographs of the night sky. They then measured, calculated and
recorded their observations in ledger books.
Eventually, Leavitt was hired at 30 cents an hour. She continued to work at the observatory
for the remaining 19 years of her life.
Leavitt was very interested in the Magellanic Clouds, two glowing hazes in space. At the
time, no one knew what the clouds were.
The Magellanic Clouds are only visible in the southern hemisphere, so Leavitt could not see
them directly. She could only look at photographic plates taken at Harvard’s observatory in
Peru. The photographs were sent to Cambridge by ship around the tip of South America.
UNIT 2 —THE BIG BANG TEXT READER
69
Using Cepheid variables
One of Leavitt’s jobs was to examine variable stars. These stars get more and less bright
because of changes inside them. Most stars don’t do this.
In the course of her work, Leavitt discovered 2,400 new variable stars.
Some variable stars, later called Cepheid variables, dim and brighten on a regular schedule.
This is called their “period.” This period can range from one day to four months.
Leavitt studied thousands of photographs of these stars. She discovered a way to determine
how bright they were (their luminosity) and how far away they were.
She found that the longer a star’s period, the brighter it was. Leavitt compared how bright a
star appeared, and how bright it actually was. By doing this, she could estimate how far
away the star actually was.
Leavitt published her first paper on the period-luminosity relationship in 1908. Four years
after that she published a table of the periods of 25 Cepheid variables.
Nine years later, in 1921, she died of cancer at age 53 in Cambridge, Massachusetts.
Leavitt's Legacy
Before Leavitt established the period-luminosity relationship, astronomers could only
measure cosmic distances up to about 100 light years. Using her discovery, astronomers
were able to estimate the Magellanic Clouds to be about 100,000 light years from Earth.
This was much farther than anyone had imagined. It meant the clouds could not be within
the Milky Way galaxy.
Edwin Hubble at the Mount Wilson Observatory near Los Angeles was studying Cepheid
variable stars. He used Leavitt’s findings and a state-of-the-art telescope to find Cepheid
variables that were extremely far away. They were so far away that they proved the
existence of other galaxies.
By 1925, most astronomers agreed that our galaxy is just one of many.
Leavitt’s first director at the Harvard College Observatory did not encourage his staff to
develop theories. He preferred only to collect data.
Another director even tried to take some of the credit for her work after her death. Leavitt is
now recognized as a key contributor to our understanding of the size of the Universe.
A modest life
Leavitt never married. She gradually became deaf, starting with an illness when she was a
young adult. She was buried in Cambridge in the family plot. Her total estate was worth
$314.91.
When she died, one of the people who worked with her wrote in her obituary: “[She] was
possessed of a nature so full of sunshine that, to her, all of life became beautified and full of
meaning.”
UNIT 2 —THE BIG BANG TEXT READER
70
Henrietta Leavitt: Measuring Distance in the Universe (740L)
By Cynthia Stokes Brown, adapted by Newsela
Henrietta Swan Leavitt studied distant stars that dim and brighten. She was able to
determine how bright these stars were and how far away they were.
Her work greatly helped other astronomers. They were able to measure huge distances in
space, find new galaxies, and begin mapping the Universe.
Leavitt was a minister's daughter. Her family moved frequently.
She went to the Society for Collegiate Instruction of Women. It was her dream to attend. In
her senior year, she found that she loved astronomy.
At the Harvard College Observatory
After graduation, Leavitt became a volunteer at the Harvard College Observatory. She
worked as a computer. At that time “computers” were women who looked at tiny dots on
photographs of the night sky. They kept detailed records of the stars and planets in
notebooks.
Leavitt was then hired at 30 cents an hour. She worked at the observatory for the rest of her
life.
Using Cepheid variables
One of Leavitt’s jobs was to examine variable stars. These stars change their brightness.
Most stars don’t.
Leavitt discovered 2,400 new variable stars.
Some variable stars dim and brighten on a regular schedule. This is called their “period.”
This period can range from one day to four months.
Leavitt studied thousands of photographs of these stars. They were called Cepheid
variables. She discovered a way to figure out how bright they were and how far away they
were.
She found that the longer a star’s period, the brighter it was. Leavitt compared how bright a
star appeared, and how bright it actually was. She could estimate how far away the star
actually was this way.
Leavitt published her first paper on the period-brightness relationship in 1908. Four years
later, she published a table of the periods of 25 Cepheid variables.
In 1921, she died of cancer at age 53 in Cambridge, Massachusetts.
Leavitt's Legacy
Before Leavitt, astronomers could only measure distances up to 100 light years away. Her
discovery improved their ability. They were now able to pinpoint some objects at 100,000
UNIT 2 —THE BIG BANG TEXT READER
71
light years away. These objects were farther away than anyone had imagined. It meant they
could not be within our Milky Way galaxy.
Edwin Hubble was studying Cepheid variables near Los Angeles. He used Leavitt’s findings
and a new telescope to find Cepheid variables that were extremely far away. They were so
far away that they could not be in our galaxy.
By 1925, most astronomers agreed that our galaxy is just one of many.
Leavitt's work faced challenges. Her first director at Harvard only wanted his staff to collect
information. He didn't want them try and put the information together as a theory. Another
director tried to take some credit for her work after her death. Yet today, Leavitt is seen as
someone who helped us understand the size of the Universe.
A modest life
Leavitt never married. She gradually became deaf, starting with an illness she had as a
young adult. She was buried in Cambridge in the family plot. All she left was worth $314.91.
Upon her death, someone who worked with her wrote: “[She] was possessed of a nature so
full of sunshine that, to her, all of life became beautified and full of meaning.”
UNIT 2 —THE BIG BANG TEXT READER
72
Tycho Brahe
After impressing the Danish king with his discoveries, Brahe built the most advanced
observatory in the world.
Tycho Brahe: The last great naked-eye astronomer (1410L)
By Cynthia Stokes Brown
Tycho Brahe was the last great naked-eye astronomer. His legacy is a star chart of
considerable accuracy and proof that the heavens were not fixed.
At the time of Brahe’s birth, the dominant model of the Universe had the Sun, Moon, and five
planets rotating around the Earth on crystalline spheres against an unchanging backdrop of
the stars. All of the star charts of that time were based on this geocentric (Earth-centered)
system.
At age 16, newly arrived at the University of Leipzig from his uncle’s palace in Copenhagen,
Brahe discovered an error in the existing star charts: a conjunction of Saturn and Jupiter that
had not been predicted. In an age of Royal Astrologers and navigation by sextant, which
relied on the positioning of celestial bodies, this was a significant error. Having shown the
existing charts to be inadequate, Brahe then devoted his life to recording the location and
movement of everything in the night sky with greater accuracy than anyone before him did.
After nearly 10 years of diligently studying and recording the night sky, using instruments
and techniques he had developed himself (the telescope was yet to be invented), Brahe was
stunned to look up one night and see a bright star where none had been before.
The heavens had changed
Using his own techniques, Brahe was able to prove that the new star (actually a supernova
now known as SN 1572) was beyond the Moon, in the celestial realm — the supposedly
unchanging backdrop of stars. The heavens had changed, and he had observed and
recorded it for science.
This discovery focused attention on Brahe from astronomers in Europe and beyond, and
greatly impressed the Danish king. With help from the king, he built one of the first real
astronomical research institutes and the most advanced observatory in the world, called
Uraniborg (Fortress of the Sky), on an island in Copenhagen Sound.
Soon after taking up his work there, he observed a comet moving beyond the “sphere” of the
Moon. By proving that the comet was not in our atmosphere, he shattered the theory that the
planets were nested around the Earth on crystalline spheres and laid the foundation for our
modern understanding of an evolving cosmos. Brahe’s influence extended to one of his most
famous students, Johannes Kepler, who used Brahe’s detailed observational record to
develop his own Laws of Planetary Motion.
UNIT 2 —THE BIG BANG TEXT READER
73
Tycho Brahe: The last great naked-eye astronomer (1170L)
By Cynthia Stokes Brown, adapted by Newsela
Tycho Brahe was the last great naked-eye astronomer. He devoted his life to recording the
location and movement of everything in the night sky with greater accuracy than anyone
before him
He produced an accurate star chart and proved that the heavens are not fixed.
At the time of Brahe’s birth in 1546, it was thought that the Sun, Moon, and five planets
rotated around the Earth attached to crystal spheres. In this model, the stars did not change.
All of the star charts of that time were based on this geocentric (Earth-centered) system.
Only 16, Brahe arrived at the University of Leipzig and discovered an error in existing star
charts. At this time, people navigated using sextants and the stars, so any error in star
charts was significant.
Brahe then dedicated his life to tracking the position and movement of all stars and planets
with great accuracy.
The heavens had changed
After nearly 10 years of studying and recording the night sky, using instruments and
techniques he had developed himself, Brahe looked up one night and saw a bright star
where none had been before. He was stunned.
Using his own techniques, Brahe was able to prove that the new star was beyond the Moon,
in the celestial realm — the supposedly unchanging backdrop of stars. The heavens had
changed, and he had observed and recorded it for science.
This discovery brought Brahe fame among astronomers around the world, and greatly
impressed the Danish king. With help from the king, he built one of the first real astronomical
research institutes and the most advanced observatory in the world, called Uraniborg
(Fortress of the Sky), on an island in Copenhagen Sound.
Soon after starting work there, he observed a comet moving beyond the “sphere” of the
Moon. By proving that the comet was not in our atmosphere, he shattered the theory that the
planets were nested around the Earth on crystalline spheres.
This laid the foundation for our modern understanding of an evolving cosmos. Brahe’s
influence extended to one of his most famous students, Johannes Kepler, who used Brahe’s
detailed observations to develop his own Laws of Planetary Motion.
Tycho Brahe: The last great naked-eye astronomer (1080L)
By Cynthia Stokes Brown, adapted by Newsela
Tycho Brahe was the last great naked-eye astronomer. He dedicated his life to recording the
location and movement of everything in the night sky with great accuracy.
UNIT 2 —THE BIG BANG TEXT READER
74
He produced an accurate star chart and proved that the heavens can change.
When Brahe was born in 1546, it was thought that the Sun, Moon, and five planets rotated
around the Earth attached to crystal spheres.
In this model, the stars did not change. All of the star charts of that time were based on this
geocentric (Earth-centered) system.
Brahe arrived at the University of Leipzig at age 16. There, he discovered an error in existing
star charts. At this time, people navigated the sea using the stars, so any error in star charts
caused serious problems.
Brahe then devoted his life to tracking the position and movement of all stars and planets
with great accuracy.
The heavens had changed
Brahe studied and recorded the night sky using instruments and techniques he had
developed himself. After 10 years, he was stunned to look up one night and see a bright star
where none had been before.
Using his own techniques, Brahe was able to prove that the new star was beyond the Moon.
It was in the celestial realm — what everyone thought was the unchanging backdrop of
stars.
The heavens had changed, and Brahe had observed and recorded it for science.
This discovery brought Brahe fame among astronomers around the world. It greatly
impressed the Danish king, who helped Brahe build one of the most advanced observatories
in the world, called Uraniborg (Fortress of the Sky), on an island in Copenhagen Sound.
Soon after starting work there, he observed a comet moving beyond the “sphere” of the
Moon. By proving that the comet was not in our atmosphere, he disproved the theory that
the planets were placed around the Earth on crystal spheres.
This laid the foundation for our modern understanding of a changing cosmos. Brahe’s
influence extended to Johannes Kepler, one of his most famous students. Kepler used
Brahe’s detailed observations to develop his own Laws of Planetary Motion.
Tycho Brahe: The last great naked-eye astronomer (780L)
By Cynthia Stokes Brown, adapted by Newsela
Tycho Brahe was the last great astronomer who worked before telescopes. He dedicated his
life to accurately recording the location and movement of everything in the night sky.
He improved the star charts of his time and proved that the heavens can change.
Brahe was born in 1546. At this time, it was thought that the Sun, Moon, and five planets
rotated around the Earth attached to spheres made of crystal.
UNIT 2 —THE BIG BANG TEXT READER
75
In this model, the stars did not change. All of the star charts of that time were based on this
geocentric system with Earth at the center of the Universe.
Brahe was only 16 when he arrived at the University of Leipzig. He immediately discovered
an error in existing star charts. People at this time used the stars to guide them. Any error in
star charts was serious.
He then devoted his life to tracking the position and movement of all stars and planets with
great accuracy.
Brahe developed his own techniques and instruments. He used these to examine the night
sky.
The heavens had changed
After 10 years of studying the heavens, he was shocked one night to see a new bright star in
the sky.
He was able to prove that this new star was beyond the Moon. Everyone had thought this
area of stars never changed.
But the heavens had changed, and Brahe had observed and recorded it for science.
This discovery made Brahe famous and impressed the Danish king. With help from the king,
he built the most advanced observatory in the world. It was called “Uraniborg,” Fortress of
the Sky.
At this new observatory, Brahe spotted a comet. He proved that the comet was not in our
atmosphere. This meant that the planets could not be attached to crystal spheres after all.
Johannes Kepler was one of Brahe's most famous students. Kepler used Brahe’s detailed
observations to develop his own Laws of Planetary Motion. In this way, we can think
of Brahe’s discoveries like a set of building blocks. They led us to discover that the cosmos
is changing.
UNIT 2 —THE BIG BANG TEXT READER
76
Science, Theology, & Copernican Revolution
Why is there such resistance to science by so many religious believers? It is partly because
faith has always been closely tied to a particular age’s picture of the natural world.
Science, Theology and the Copernican Revolution (1340L)
By John F. Haught
At the beginning of the scientific age, people were not only intellectually shocked but also
spiritually threatened by the news that the Sun was being asked to exchange places with the
Earth. In 1612, the devout Anglican poet John Donne wrote these anguished lines in his
poem “Anatomy of the World”:
And new philosophy calls all in doubt,
The element of fire is quite put out;
The sun is lost, and th’ earth, and no man’s wit
Can well direct him where to look for it
’Tis all in pieces, all coherence gone; (lines 205–208, 213)
The “new philosophy” that Donne refers to — since there was no word for “science” at the
time — is the Copernican revolution. In 1610, two years before Donne’s poem appeared,
Galileo Galilei (1564–1642) had published the world’s first scientific bestseller, The Starry
Messenger. This revolutionary work argued that the heavens are not organized the way
astronomers, philosophers, and theologians had taught for ages. As far as Donne was
concerned, however, Galileo’s ideas threatened not only the entrenched cosmology of Plato,
Aristotle, and Ptolemy but also the religious sensibilities associated for centuries with an
Earth-centered (geocentric) vision of nature.
In 1543, the Polish astronomer and cleric Nicolaus Copernicus had already proposed that
movements in the skies could be predicted more accurately than before if one supposes that
the Earth and other planets revolve around the Sun. However, prior to Galileo’s release
of The Starry Messenger, Copernicus’s new model of the heavens seemed little more than
an abstract mathematical scheme for making astronomical predictions. Those who read
Copernicus’s work often took it simply as an experiment in thought rather than a realistic
representation of the heavens and Earth. For Galileo, on the other hand, the Copernican
system was not a mental exercise but an approximation of the way the heavens really do
hang together.
In his later and more controversial work, Dialogue of the Two Chief World Systems, Galileo
could scarcely conceal his growing conviction that the Copernican universe must now
replace the Ptolemaic one. His increasingly bold teachings and writings eventually led, in
UNIT 2 —THE BIG BANG TEXT READER
77
1633, to the Catholic Church’s notorious condemnation of Galileo’s new science and to his
being put under house arrest until his death in 1642.
The Church now regrets its mistake and insists that there can be no genuine conflict
between science and faith. However, in the seventeenth century, Donne and many of his
contemporaries interpreted the new science as a great threat to spiritual as well as
intellectual life: “’Tis all in pieces, all coherence gone,” the poet worried, expressing a kind of
religious anxiety that still occurs among many people of faith when they hear about new
scientific discoveries.
A crossroads for science and theology
Why is there such fierce resistance to science by so many religious believers? It is partly
because faith, theology, and spirituality have always been closely tied to a particular age’s
picture of the natural world. In biblical times, for example, the religious drama of salvation
assumed a three-level picture of the cosmos: the heavens fixed firmly above; the Earth
beneath; and then, lower still, the underworld (Sheol), the dwelling place of the dead. In the
seventeenth century, most religious believers took the biblical portrait of nature literally.
Certain passages in the Bible insinuated that the Sun moves and the Earth stands still.
Thus, the Bible seemed to support the Ptolemaic picture of the Universe, while Copernican
astronomy seemed to contradict God’s word.
Galileo’s opinion, however, was that the Bible should not be read as a source of scientific
information, a position that the Catholic Church now officially accepts. The Bible has nothing
to contribute to any knowledge that human beings can gather on their own, that is, with their
own natural powers of observation and mathematical reasoning. Galileo continued to believe
that the Bible was inspired literature, but he cautioned that people miss the religious
meaning of Scripture whenever they treat it as a source of scientific truths.
In his Letter to the Grand Duchess Christina, Galileo claimed the support of the renowned
early Christian writer Augustine of Hippo (354–430 CE). Augustine had pointed out that
Christian instruction should not insist that converts to Christianity take the cosmology of the
Bible literally. To do so would only prevent those who can’t accept the literal cosmology from
taking the religious meaning seriously in the Scriptures.
Some historians and scientists have assumed wrongly that Galileo’s clash with his Church
means that he saw a conflict between science and faith. However, he never thought of his
observations and ideas as contrary to the basic teachings of his faith. For him science has
little or nothing to do with theology. Nonetheless, the case of Galileo and the entire
Copernican revolution, as Donne’s poem indicates, did have implications for human
spirituality.
“Spirituality” is the quest for a vision of reality that will give people courage, hope, and some
degree of happiness in the midst of life’s inevitable tribulations. For centuries, Ptolemaic
astronomy had provided a framework for spiritual inspiration. For most people, the skies held
visible hints of a better world. The perfectly circular movement of heavenly bodies and the
faultless spherical geometry of the Sun and Moon, for example, offered at least a hint of the
infinite beauty that seemed to lie beyond our shadowy and perishable world.
UNIT 2 —THE BIG BANG TEXT READER
78
The new science, however, seemed to call all of this “in doubt,” as Donne puts it. With the
more precise astronomical measurements by Copernicus, Brahe, Kepler, and Galileo, the
heavens were undergoing a series of demotions that dimmed their luster. Consequently, the
Copernican revolution produced a massive upheaval not only in science but also in spiritual
life.
The final blow
Ancient astronomy, philosophy, and theology had all assumed that the superlunary world —
the world beyond the orbit of the moon — is special. Above the Moon’s orbit the heavens
seemed immune to change, novelty, and collapse. Their immutability pointed both minds
and hearts toward a better and more permanent world than that which existed on Earth.
Aristotle (384–322 BCE) had even portrayed the heavens as a “quintessential” (fifth) kind of
reality far surpassing in value the four mundane elements (earth, air, fire, and water) that
make up the sublunary world “down here.” In contrast to imperfect earthly things that change
and eventually perish, the heavens seemed to mirror the changeless eternity of God.
Modern astronomy, however, gradually robbed the heavens of their transparency to God —
at least for many thoughtful people like Donne. Tycho Brahe (1546–1601), for example,
demonstrated to his shocked contemporaries that comets and supernovae — both implying
change and novelty — existed beyond, rather than beneath, the Moon’s orbit. Thus the
superlunary heavenly vault showed itself to be imperfect after all and could no longer
adequately represent the unchanging perfection of God. Johannes Kepler (1571–1630),
moreover, calculated that planets move in “ugly” elliptical patterns rather than perfectly
circular orbits. Careful new observations increasingly demonstrated that the heavens, like
things on Earth, are ordinary after all.
It was left to Galileo, however, to deliver the decisive insult to the heavens, although even he
still believed that celestial orbits were perfectly circular. His lively writings delivered the news
that the Moon is pocked with craters, Venus goes through phases, Jupiter has satellites, and
the Sun is blemished with dark spots.
Finding perfection in change
Galileo’s view of the Copernican model was both simple and profound. What is so great, he
asked, about changelessness? And what is so bad about the dirty, changing Earth that we
inhabit? Look carefully at what lies beneath our feet and not just over our heads! If the total
amount of dirt on Earth were as small as the tiny amount of precious jewels, what ruler or
king would not gladly exchange all his diamonds for just enough dirt to bring forth a
tangerine or jasmine tree?
Isn’t life, in other words, a much richer symbol of perfection than the mistaken idea of
changeless heavens could ever be? Little did Galileo know, however, of the remarkably tight
narrative connection that astronomy and astrophysics would eventually draw between the
existence of life and the seemingly unchanging and impersonal heavens.
UNIT 2 —THE BIG BANG TEXT READER
79
Science, Theology and the Copernican Revolution (1100L)
By John Haught, adapted by Newsela
At the beginning of the scientific age, people were shocked by the news that the Sun and the
Earth were switching places. Not only that, they felt spiritually threatened by the news.
In 1612, poet John Donne, who was a devout Christian, wrote these lines:
And new philosophy calls all in doubt,
The element of fire is quite put out;
The sun is lost, and th’ earth, and no man’s wit
Can well direct him where to look for it
’Tis all in pieces, all coherence gone;
The “new philosophy” that Donne refers to is the Copernican Revolution. There was no word
for “science” at the time.
Two years before Donne wrote those words, Galileo Galilei had published the world’s first
scientific bestseller, The Starry Messenger. This revolutionary book argued that the heavens
were different than everyone had thought.
Polish astronomer Nicolaus Copernicus had pointed out that movements in the sky could be
predicted more easily if you assumed that the Earth revolved around the Sun. But people at
the time accepted this as a thought experiment — not the way things actually were.
For Galileo, on the other hand, the Copernican system was not a mental exercise, but a
description of the way things really worked.
After Galileo published his later and more controversial work, Dialogue of the Two Chief
World Systems, the Catholic Church famously condemned him. He lived under house arrest
until his death in 1642.
The Church now regrets its mistake and insists that there is no genuine conflict between
science and faith. However, people like Donne in the seventeenth century certainly felt that
science was a threat to their spiritual life. This anxiety still occurs among many people of
faith when they hear about new scientific discoveries.
A crossroads for science and theology
Why is there such fierce resistance to science by so many religious believers?
It is partly because religion often gives us a picture of the natural world. For example, in
biblical times, people assumed a three-level picture of the cosmos: the heavens fixed firmly
above; the Earth beneath; and then, lower still, the underworld, the dwelling place of the
dead.
In the seventeenth century, most religious believers took the biblical portrait of nature
literally. Certain Bible passages implied that the Sun moves and the Earth stands still. The
UNIT 2 —THE BIG BANG TEXT READER
80
Bible seemed to support the Ptolemaic picture of the Universe, while Copernican astronomy
seemed to contradict God’s word.
Galileo believed, however, that the Bible should not be read as a source of scientific
information. The Catholic Church now officially accepts this position. Galileo still believed the
Bible was inspired literature, but he warned people that they miss the religious meanings
when they treat the text as a source of scientific truths.
Some historians and scientists have assumed wrongly that Galileo’s clash with his Church
means that he saw a conflict between science and faith. However, he never thought of his
observations and ideas as contrary to the basic teachings of his faith. For him, science has
little or nothing to do with theology.
But the case of Galileo and the Copernican revolution did have implications for human
spirituality.
“Spirituality” is the quest for a vision of reality that will give people courage, hope, and some
degree of happiness in the midst of life’s inevitable tribulations.
For centuries, Ptolemy’s worldview had provided a framework for spiritual inspiration. The
skies held visible hints of a better world.
The perfectly circular orbits of the planets and the perfect spheres of the Sun and Moon
seemed to offer a hint of the infinite beauty that lies beyond our shadowy and temporary
world.
All this was in doubt, though, thanks to the new science. Copernicus, Brahe, Kepler, and
Galileo were making more accurate astronomical measurements. They were finding that the
heavens were not so “perfect” after all.
Their findings caused a massive change not only in science, but also in spiritual life.
The final blow
Ancient astronomy, philosophy, and religion had assumed that the skies beyond the Moon
were special. The heavens above the Moon seemed unchangeable, indestructible.
Because the skies above seemed to be unchanging, they pointed both hearts and minds
toward a better and more permanent world than the one on Earth.
Aristotle had called the heavens a fifth kind of reality, better than the four common elements
(earth, air, fire and water) that made up the world “down here.” In contrast to imperfect
earthly things that change and eventually perish, the heavens seemed to mirror the
changeless eternity of God.
Modern astronomy gradually robbed the heavens of their perfection, and their transparency
to God.
Tycho Brahe (1546–1601), for example, shocked people by showing that comets and
supernovae existed beyond the Moon. Both of these show change and newness in an area
that was thought to be perfectly stable.
UNIT 2 —THE BIG BANG TEXT READER
81
Now the sky above showed itself to be imperfect after all. It could no longer adequately
represent the unchanging perfection of God.
Johannes Kepler (1571–1630), moreover, calculated that planets move in “ugly” elliptical
(oval) patterns rather than perfectly circular orbits. Careful new observations increasingly
demonstrated that the heavens, like things on Earth, are ordinary after all.
Galileo, though, delivered the final insults to the idea of perfection in space. He spread the
news that the Moon is covered with craters, Jupiter has satellites, and the Sun has dark
spots on it.
Finding perfection in change
Galileo’s view of the Copernican model was both simple and profound. What is so great, he
asked, about changelessness? And what is so bad about the dirty, changing Earth that we
inhabit? Look carefully at what lies beneath our feet and not just over our heads!
Isn’t life, in other words, a much richer symbol of perfection than the mistaken idea of
changeless heavens could ever be?
Science, Theology and the Copernican Revolution (970L)
By John Haught, adapted by Newsela
At the beginning of the scientific age, people were shocked that the Sun and the Earth were
switching places. Not only that, they felt spiritually threatened by the news.
In 1612, poet John Donne, a committed Christian, wrote these lines:
And new philosophy calls all in doubt,
The element of fire is quite put out;
The sun is lost, and th’ earth, and no man’s wit
Can well direct him where to look for it
’Tis all in pieces, all coherence gone;
The “new philosophy” that Donne refers to is the Copernican Revolution and science in
general. Though there was no word for “science” at the time.
Donne wrote those words two years after Galileo Galilei had published The Starry
Messenger. This bestselling book changed long-held views about the skies above.
Polish astronomer Nicolaus Copernicus had imagined a world where the Earth revolves
around the Sun. But people at the time just thought he was doing a thought experiment.
For Galileo, on the other hand, the Copernican system was not a mental exercise, but a
description of the way things really worked.
The Catholic Church famously called Galileo wrong and sentenced him to the rest of his life
under house arrest.
UNIT 2 —THE BIG BANG TEXT READER
82
The Church now regrets its mistake and insists that there is no real conflict between science
and faith. However, people like Donne in the seventeenth century certainly felt that science
was a threat to their spiritual life. This anxiety still occurs among many religious people when
they hear about new scientific discoveries.
A crossroads for science and theology
Why is there such fierce resistance to science by so many religious believers?
It is partly because religion often gives us a picture of the natural world. Science can disrupt
this.
For example, in biblical times, people thought of the cosmos in three levels: the heavens
above, never moving; the Earth beneath; and lower still, the underworld, the land of the
dead.
In the seventeenth century, most religious believers took the biblical picture of nature
literally. Certain Bible passages implied that the Sun moves and the Earth stands still.
The Bible seemed to support the Ptolemaic picture of the Universe, while Copernican
astronomy seemed to contradict God’s word.
Galileo believed, however, that the Bible should not be read as a source of scientific
information. The Catholic Church now officially accepts this position. Galileo still believed the
Bible was special, but he said that people missed the religious meanings when they treated
it as a source of scientific truths.
Some historians and scientists have assumed that Galileo’s fight with his Church means that
he saw a conflict between science and faith. This is not true. For him science has little or
nothing to do with religion.
But the discoveries of Copernicus and Galileo did have consequences for human spirituality.
“Spirituality” is the quest for a vision of reality that will give people courage, hope, and some
degree of happiness in the midst of life’s inevitable tribulations.
For centuries, people had taken comfort in Ptolemy’s view of an ordered and regular
universe.
In this view, planets orbited on perfectly circular paths. The Sun and Moon were perfect
spheres. This perfection seemed to offer a hint of the infinite beauty that lies beyond our
shadowy and temporary world.
The new science put this all in doubt. Copernicus, Brahe, Kepler, and Galileo were making
more accurate astronomical measurements. They found that the heavens were not so
“perfect” after all.
Their findings caused a massive change not only in science, but also in spiritual life.
UNIT 2 —THE BIG BANG TEXT READER
83
The final blow
Ancient astronomy, philosophy, and religion had all assumed that the skies past the Moon
were special. The heavens above the Moon seemed unchangeable, indestructible.
Because the skies above seemed to be unchanging, they pointed hearts and minds toward a
better and more permanent world than the one on Earth.
Aristotle had called the heavens a fifth kind of reality, better than the four common elements
(earth, air, fire and water) that made up the world “down here.” While things on Earth change
and eventually die, the heavens seemed to mirror the changeless eternity of God.
Modern astronomy gradually robbed the heavens of their perfection, and their connection to
God.
Tycho Brahe, for example, shocked people by showing that comets and supernovae existed
beyond the Moon. Both of these show change and newness in an area that was thought to
be perfectly stable.
Now the sky above was imperfect after all. It could no longer represent the unchanging
perfection of God.
Other scientists also helped to destroy the image of the heavens as perfect and unchanging.
Johannes Kepler showed that planets’ orbits are not perfect circles. Rather, they travel in
oval-like elliptical patterns. Galileo discovered that the Moon is covered with craters. He
found Jupiter has satellites and the Sun has dark spots on it.
Careful new observations increasingly demonstrated that the heavens, like things on Earth,
are ordinary after all.
Finding perfection in change
Galileo was not bothered by these imperfections. What is so great about changelessness?
he asked. And what is so bad about the dirty, changing Earth that we inhabit? Look carefully
at what lies beneath our feet and not just over our heads!
Isn’t life, in other words, a much richer symbol of perfection than the mistaken idea of
changeless heavens could ever be?
Science, Theology and the Copernican Revolution (780L)
By John Haught, adapted by Newsela
When Galileo announced that the Sun was at the center of our Solar System, people were
shocked. Many people felt the news contradicted their religious beliefs.
Poet John Donne was a committed Christian. He wrote these lines in 1612:
And new philosophy calls all in doubt,
The element of fire is quite put out...
UNIT 2 —THE BIG BANG TEXT READER
84
The “new philosophy” Donne mentions is science. Donne wrote those words two years after
Galileo Galilei published The Starry Messenger. In this book, Galileo presented a world that
was very different than what people had believed.
Copernicus had thought about the Earth revolving around the Sun. At the time, though,
people thought he was just doing a thought experiment. Galileo knew that this was how the
world really worked.
The Catholic Church famously called Galileo wrong. It forced him to spend the rest of his life
confined to his house.
The Church now regrets its mistake. It insists there is no real conflict between science and
faith. However, for many religious people, new scientific discoveries can bring worry.
A crossroads for science and theology
Why do so many religious believers seem to be against science? It is partly because religion
paints a picture of the natural world. Science can disturb this picture.
For example, in biblical times, people thought of the Universe in three levels. First were the
heavens above. They were perfect and unchanging. Below the heavens was the Earth.
Below the Earth was the underworld, the land of the dead.
In the 1600s, most religious believers took the Bible word for word. It seemed to support the
idea that Earth was at the center of the Universe. So had Ptolemy and Aristotle. Galileo and
Copernicus seemed to be going against the Bible.
Galileo believed the Bible was special. But he didn't think it should be read for scientific
information. The Catholic Church now agrees with him.
Some assume that because Galileo argued with the Church, he saw a conflict between
science and faith. This is not true. For him, science and religion were almost completely
separate.
But the discoveries of Copernicus and Galileo did affect spirituality.
Life has unavoidable difficulties. "Spirituality” is what gives people courage, hope, and
happiness to face those difficulties. For centuries, people were comforted by Ptolemy’s view
of an orderly Universe.
In this view, planets traveled on perfectly circular paths. The Sun and Moon were perfect
spheres. In this perfection, people saw a hint of the unending beauty that lies beyond our
world.
The new science put this all in doubt. Copernicus, Brahe, Kepler, and Galileo were making
new astronomical measurements. Their findings showed the heavens were not so “perfect”
after all.
Their discoveries greatly changed spiritual life.
UNIT 2 —THE BIG BANG TEXT READER
85
The final blow
In ancient astronomy, philosophy and religion, the skies beyond the Moon were special.
They seemed unchanging, indestructible. The skies above seemed permanent and perfect.
They pointed to a better and more permanent world than the one here on Earth.
Aristotle called the heavens a fifth kind of reality. The heavens were better than the four
common elements down here — earth, air, fire and water. While all things on Earth change
and eventually die, the heavens showed the unchanging, never-ending nature of God.
Modern astronomy gradually showed that the heavens weren’t perfect. They weren’t a
reflection of a perfect God anymore.
Other scientists helped to end the idea that the heavens are perfect and
unchanging. Johannes Kepler showed that planets move in oval patterns. Previously, people
thought they moved in perfect circles. Tycho Brahe showed that comets and exploding stars
were out beyond the Moon. He shocked people by showing changing heavens. Galileo
showed that the Moon is covered with craters. He pointed out that the Sun has dark spots on
it.
Careful observation showed that the heavens are ordinary after all.
Finding perfection in change
Galileo was religious, but he was not bothered by these imperfections. What’s so great
about not changing, he asked. And what is so bad about the dirty, changing Earth where we
live? Look carefully at what lies beneath our feet and not just over our heads!
Isn’t life a better symbol of perfection than changeless heavens could ever be?
UNIT 2 —THE BIG BANG TEXT READER
86
The Vatican Observatory
Equipped with one of the world’s oldest telescopes, the Catholic Church has sought to
answer a question of interest to people of all faiths: How did this Universe come to be?
The Vatican Observatory: At the Intersection of Faith and Science
(1330L)
By Michelle Feder
Every summer, the pope leaves the heat of Rome and heads to his vacation home at Castel
Gandolfo, in the Alban hills. The sixteenth century monastery sits on a high ridge, a perfect
spot to view and reflect upon the heavens.
Castel Gandolfo serves as the main headquarters for the Vatican Observatory, one of the
oldest astronomical institutes in the world. It operates under the jurisdiction of the pope and
the Roman Catholic Church.
Since 1891, when the observatory was founded, the pope’s astronomers have used it to
study the night sky. Equipped with one of the world’s oldest telescopes, they have applied
their scientific expertise to fundamental questions that engage people of all faiths: How did
this Universe come to be, and what is our place in it?
For more than a century, this research center has been a bridge between theology and
science. In addition to the telescopes, private rooms, working quarters, and kitchen, the
facility at Castel Gandolfo has a museum of meteorites and two large libraries containing
more than 22,000 volumes, including historic works by Copernicus, Galileo, Newton, and
Kepler. Every summer, the astronomers at the observatory update the pope about their
work.
Father George Coyne, who was appointed director of the Vatican Observatory by Pope John
Paul I in 1978, remembers well his early experiences at the Vatican Observatory. He recalls
the excitement of observing the stars from the telescopes inside Gandolfo’s notable domes,
and the satisfaction that came from doing “good science” while serving the Church. “Science
is an attempt to explain natural events by natural causes,” says Coyne. “The Church has a
serious interest in understanding the Universe and everything in it.” But in his view, “True
science, good science, does not conflict with religious belief.”
Roots in controversy
The relationship between the papacy and astronomy has not always been so smooth. Earlier
Christian astronomers may have tried to detect which wandering star or supernova led three
wise men to a stable in Bethlehem — the birthplace of Jesus Christ. More precisely, papal
interest in stargazing can be traced to more than four centuries ago, when Pope Gregory XIII
UNIT 2 —THE BIG BANG TEXT READER
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(papal reign 1572–1585) set up a committee to examine the implications for science related
to the pope’s 1582 reform of the calendar.
Enter Italian astronomer Galileo Galilei (1564–1642), whom Albert Einstein called “the father
of modern science.” Using observational evidence, Galileo challenged the teachings of the
past. In 1609 and 1610, Galileo used a telescope of his own design to see the surface of the
Moon, the phases of Venus, and the moons of Jupiter, compiling strong evidence for
Copernicus’s Sun-centered theory (Farndon, 2007). Galileo, who was born and educated in
Pisa, first visited Rome in March 1611 to demonstrate the power of the telescope to Church
officials.
Galileo suggested that his studies supported the theories of Polish mathematician and
scholar Nicolaus Copernicus (1473–1543). It was Copernicus who theorized — a century
before Galileo — that the Earth moved around the Sun, and not vice versa.
But the Catholic Church, which backed the Earth-centered, geocentric teachings of Aristotle
and Ptolemy, was not accepting of these new ideas. The Church was already dealing with
the Reformation, a movement that challenged the authority of the pope and the Catholic
Church in Rome. In 1542, the Church began the Inquisition, an organization that made
decisions on questions of morality and faith. It analyzed books and individuals to determine if
what they said agreed with the Bible. Some people were sentenced to death for airing their
beliefs.
The Inquisition found Galileo’s writings of an Earth in motion around the Sun heretical and
incorrect, and banned the teaching of Copernicus’s theories. Galileo was forced to renounce
his approval of the Copernican heliocentric model. In 1633, he was convicted of heresy for
defending that model and placed under a life sentence of house arrest. He died on January
8, 1642, still in confinement.
Dedication to discovery
Nevertheless, the Church has, since Galileo’s time, expressed an interest in astronomical
research. Three early observatories were founded by the papacy: the Observatory of the
Roman College (1774– 1878); the Observatory of the Capitol (1827–1870); and the first
incarnation of the Vatican Observatory (1789–1821), housed in a building called the Tower
of the Winds that still exists within the Vatican.
A breakthrough came in the mid-nineteenth century with research conducted at the Roman
College by Father Angelo Secchi. He was the first to classify stars according to their spectra,
the color of light that stars emit. Modern spectroscopy is very important in astronomy today
because scientists know that different elements have their own emission spectra, and can
contribute to the “chemical signature” that a star’s light reveals.
On March 14, 1891, Pope Leo XIII (papal reign 1878–1903), in an attempt to counter the
persistent perception of hostility by the Church toward science, set up another small
astronomical observatory on a hill behind the dome of Saint Peter’s Basilica.
In 1910, Pope Pius X (papal reign 1903–1914) gave the observatory a new, larger space at
a villa built in the Vatican Gardens by Leo XIII. From 1914 to 1928, the observatory
UNIT 2 —THE BIG BANG TEXT READER
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contributed to the Astrographic Catalogue, an ambitious map of the sky that was undertaken
in conjunction with 17 observatories around the world. The Vatican printed 10 volumes,
which listed the brightness and positions of 481,215 stars.
By the 1930s, however, light pollution from the city of Rome prevented the study of the
fainter stars and galaxies. Pope Pius XI (papal reign 1922–1939) relocated the observatory
to Castel Gandolfo and put it in the hands of Jesuits; three new telescopes were
constructed, an astrophysical laboratory for spectral analysis of the light from distant
celestial bodies was installed, and research programs began on Cepheid variables. A
Schmidt wide-angle telescope, installed in 1957, allowed for further work on the
classification of stars.
Advances in research
The telescopes at Castel Gandolfo are rarely used anymore for astronomical research,
reserved instead for visiting groups and summer-school students. All serious study is
performed using other telescopes around the world, mainly in Arizona.
Father Coyne helped establish the Vatican Observatory Research Group (VORG) in Tucson,
Arizona. Problems with nighttime viewing conditions around Rome spurred the need for this
mountaintop institute, founded in 1981. In 1993, the observatory completed the construction
of the Vatican Advanced Technology Telescope (VATT) on Mount Graham, Arizona; its
optical mirrors are among the most exact surfaces ever made for a ground-based telescope.
And the telescope’s observational abilities are augmented by the skies above — some of the
clearest and darkest in North America.
The observatory’s 15 staff members collaborate with astronomical research institutes in
countries around the globe, and as members of the International Astronomical Union and the
International Center for Relativistic Astrophysics.
“The first priority of the Vatican Observatory is scientific research, and the VATT is our tool,”
said VORG director Jose G. Funes at a February 2009 research seminar at the University of
Arizona. “We are priests and religious men, but we also are scientists …Astronomy is our
main service to the church” (Stiles, 2009).
New points of view
On the evening of September 16, 2009, Pope Benedict XVI inaugurated the new facility of
the Vatican Observatory with a prayer and blessing. The facility includes two floors in a
renovated building on the grounds of the Pontifical Villas of Gandolfo, and has a library,
conference room, offices, guest quarters, laboratory, and chapel (Vatican Observatory
Newsletter, Fall 2009, p. 1). The unveiling took place in what was dubbed the “International
Year of Astronomy,” which honored Galileo’s first scientific use of the telescope 400 years
prior.
The subject of Galileo has remained a tricky one for the Church throughout the years. In
1992, Pope John Paul II (papal reign 1978–2005) expressed regret at the way Galileo had
been treated, stating, “The error of the theologians of the time, when they maintained the
UNIT 2 —THE BIG BANG TEXT READER
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centrality of the Earth, was to think that our understanding of the physical world’s structure
was, in some way, imposed by the literal sense of sacred Scripture.” (BBC News, 2008).
Father Coyne, who ran the Vatican Observatory throughout Pope John Paul II’s reign, says,
“The Church is a human institution, and a human institution can make, and has made,
mistakes.” In the 1600s, Coyne says, the Church believed that Galileo contradicted
Scripture. “We can’t judge by the modern day what happened 300 to 400 years ago,” Coyne
continues. “We do have to say the Church was wrong in thinking Scripture teaches science
… The Church now knows that.”
Such thinking didn’t change overnight. The sense and sensibility of the appropriate
relationship between faith and reason, science and Scripture, has evolved over time. Each
pope’s approach may yield subtle shifts. In 1998, Pope John Paul II wrote in an official letter:
Faith and reason are like two wings on which the human spirit rises to the contemplation of
truth; and God has placed in the human heart a desire to know the truth — in a word, to
know himself — so that, by knowing and loving God, men and women may also come to the
fullness of truth about themselves.
Near the end of the same letter, he said:
I cannot fail to address a word to scientists, whose research offers an ever greater
knowledge of the Universe as a whole and of the incredibly rich array of its component parts,
animate and inanimate, with their complex atomic and molecular structures. So far has
science come, especially in this century, that its achievements never cease to amaze us. In
expressing my admiration and in offering encouragement to these brave pioneers of
scientific research, to whom humanity owes so much of its current development, I would
urge them to continue their efforts without ever abandoning the sapiential horizon within
which scientific and technological achievements are wedded to the philosophical and ethical
values which are the distinctive and indelible mark of the human person.
But the papal understanding of the right rapport between reason and faith is still emerging.
In January 2008, Pope Benedict XVI (papal reign 2005–2013) canceled a visit to a university
in Rome where lecturers and students had protested against his views on Galileo. The
university’s rector cited Benedict’s 1990 statement, when, as Cardinal Ratzinger, he said the
Church’s verdict against Galileo had been “rational and just.”
However, in 2009 Pope Benedict XVI dedicated a plaque that attests to the “Church’s
steadfast support for the work of the observatory at the nexus of faith and science.” Father
Coyne emphasizes that Galileo paved the way for a harmonious relationship between
religious belief and scientific inquiry. “Galileo anticipated by four centuries what the Church
would finally say about the interpretation of Scripture,” he says. “Galileo said that Scripture
was written to teach us how to go to heaven, not how the heavens go.”
And Galileo never turned away from the faith that had sentenced him. “[He] was a devout
Catholic and was not trying to start a conflict between science and religion,” writes Rachel
Hilliam in Galileo Galilei: Father of Modern Science. “He believed that the Bible was there to
instruct people in how to get to heaven and was not meant to be a scientific book explaining
how the Universe worked” (p. 78) His recantation, or confession, on June 22, 1633, “did not
UNIT 2 —THE BIG BANG TEXT READER
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include two points because Galileo was opposed to them: that he was not a good Catholic
and that he had deceived others by publishing his book” (p. 79).
Coyne believes faith and science complement each other. He says, “Faith is: ‘God loves
me.’ I accept God’s love. I try to return that love to God each day.” At the same time, he
notes, “We are human beings. Science is instrumental to improving our knowledge of the
Universe. But we will never have the final answer.”
The Vatican Observatory: At the Intersection of Faith and Science
(1100L)
By Michelle Feder, adapted by Newsela
Every summer, the pope leaves the heat of Rome and heads to his vacation home at Castel
Gandolfo, in the Alban hills, overlooking Lake Albano. The sixteenth century monastery sits
on a high ridge, a perfect spot to view and reflect upon the heavens.
Castel Gandolfo is the main headquarters for the Vatican Observatory, one of the oldest
astronomical institutes in the world. It is run by the pope and the Roman Catholic Church.
Since 1891, when the observatory was founded, the pope’s astronomers have used it to
study the night sky. Equipped with one of the world’s oldest telescopes, they have applied
their scientific expertise to fundamental questions that engage people of all faiths: How did
this Universe come to be, and what is our place in it?
For more than a century, this research center has been a bridge between theology and
science. Castel Gandolfo has a museum of meteorites and two large libraries containing
more than 22,000 volumes, including historic works by Copernicus, Galileo, Newton, and
Kepler. Every summer, the astronomers at the observatory update the pope about their
work.
Father George Coyne was appointed director of the Vatican Observatory by Pope John Paul
I in 1978. He recalls the satisfaction that comes from doing “good science” while serving the
church.
“Science is an attempt to explain natural events by natural causes,” says Coyne. “The
Church has a serious interest in understanding the Universe and everything in it.”
In his view, “True science, good science, does not conflict with religious belief.”
Roots in controversy
The relationship between the popes and astronomy has not always been so smooth.
In the sixteenth century, Pope Gregory XIII reformed the calendar and set up a committee to
examine the implications for science.
Enter Italian astronomer Galileo Galilei, whom Albert Einstein called “the father of modern
science.” Using observational evidence, Galileo challenged the teachings of the past.
UNIT 2 —THE BIG BANG TEXT READER
91
In 1609 and 1610, Galileo used a telescope of his own design to see the surface of the
Moon, the phases of Venus, and the moons of Jupiter. These were all strong evidence for
Copernicus’s Sun-centered theory.
Galileo suggested that his studies supported the theories of Polish mathematician and
scholar Nicolaus Copernicus. Copernicus had theorized — a century before Galileo — that
the Earth moved around the Sun, and not vice versa.
But the Catholic Church, which backed the Earth-centered, geocentric teachings of Aristotle
and Ptolemy, was not accepting of these new ideas.
The Church was already dealing with the Reformation, a movement that challenged the
authority of the pope and the Catholic Church in Rome. In 1542, the Church began the
Inquisition, an organization that made decisions on questions of morality and faith. It
analyzed books and individuals to determine if what they said agreed with the Bible. Some
people were sentenced to death for their beliefs.
The Inquisition found Galileo’s writings of an Earth in motion around the Sun heretical and
incorrect, and banned the teaching of Copernicus’s theories. Galileo was forced to take back
his approval of the Copernican heliocentric model. In 1633, he was convicted of heresy for
defending that model and placed under a life sentence of house arrest. He died on January
8, 1642, still in confinement.
Dedication to discovery
Nevertheless, the Church has, since Galileo’s time, expressed an interest in astronomical
research. Three different observatories were founded by popes in the eighteenth and
nineteenth centuries.
Vatican astronomers made a major breakthrough in the mid-nineteenth century. Father
Angelo Secchi was the first to classify stars according to their spectra, the color of light they
emit. Modern spectroscopy is very important in astronomy today because scientists know
that different elements have their own emission spectra, and can contribute to the “chemical
signature” that a star’s light reveals.
Today’s Vatican Observatory traces its roots back to 1891 when Pope Leo XIII set up a
small observatory on the Vatican grounds. In 1910, Pope Pius X gave the observatory a
new, larger space.
From 1914 to 1928, the observatory contributed to the Astrographic Catalogue, an ambitious
map of the sky that was undertaken in conjunction with 17 observatories around the world.
By the 1930s, light pollution from Rome prevented the study of the fainter stars and galaxies.
Pope Pius XI moved the observatory to Castel Gandolfo. Three new telescopes were
constructed, an astrophysical laboratory was installed, and research programs began on
Cepheid variable stars.
UNIT 2 —THE BIG BANG TEXT READER
92
Advances in research
The telescopes at Castel Gandolfo are rarely used anymore for astronomical research. They
are reserved instead for visiting groups and summer-school students. All serious study is
performed using other telescopes around the world, mainly in Arizona.
Father Coyne helped establish the Vatican Observatory Research Group (VORG) in Tucson,
Arizona. Problems with nighttime viewing conditions around Rome created the need for this
mountaintop institute, founded in 1981.
In 1993, the observatory completed construction of a state-of-the-art telescope. The Vatican
Advanced Technology Telescope (VATT) has optical mirrors that are among the most exact
surfaces ever made for a ground-based telescope.
The skies above Arizona are dark and clear, making the telescope even more useful.
The observatory’s 15 staff members work with astronomers around the world.
“The first priority of the Vatican Observatory is scientific research, and the VATT is our tool,”
said VORG director Jose G. Funes. “We are priests and religious men, but we also are
scientists. Astronomy is our main service to the Church.”
New points of view
The subject of Galileo has remained a tricky one for the Church throughout the years. In
1992, Pope John Paul II expressed regret at the way Galileo had been treated. He said,
“The error of the theologians of the time, when they maintained the centrality of the Earth,
was to think that our understanding of the physical world’s structure was, in some way,
imposed by the literal sense of sacred Scripture.”
Father Coyne, who ran the Vatican Observatory says, “The Church is a human institution,
and a human institution can make, and has made, mistakes.”
In the 1600s, Coyne says, the Church believed that Galileo contradicted Scripture. “We can’t
judge by the modern day what happened 300 to 400 years ago,” Coyne continues. “We do
have to say the Church was wrong in thinking Scripture teaches science. The Church now
knows that.”
Such thinking didn’t change overnight. Each pope takes his own approach. In 1998, Pope
John Paul II wrote in an official letter: "Faith and reason are like two wings on which the
human spirit rises to the contemplation of truth."
But the balance between faith and reason is sometimes difficult for popes to manage.
Pope Benedict XVI was criticized in 2008 for saying the Church’s verdict against Galileo had
been “rational and just.”
However, in 2009, Pope Benedict XVI dedicated a plaque that attests to the “Church’s
steadfast support for the work of the observatory at the nexus of faith and science.”
Father Coyne emphasizes that Galileo paved the way for a harmonious relationship between
religious belief and scientific inquiry.
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“Galileo anticipated by four centuries what the Church would finally say about the
interpretation of Scripture,” he says. “Galileo said that Scripture was written to teach us how
to go to heaven, not how the heavens go.”
And Galileo never turned away from the faith that had sentenced him.
“Galileo was a devout Catholic and was not trying to start a conflict between science and
religion,” writes Rachel Hilliam in a book on Galileo. “He believed that the Bible was there to
instruct people in how to get to heaven and was not meant to be a scientific book explaining
how the Universe worked.”
Coyne believes faith and science complement each other. He says, “Faith is: ‘God loves
me.’ I accept God’s love. I try to return that love to God each day.” At the same time, he
notes, “We are human beings. Science is instrumental to improving our knowledge of the
Universe. But we will never have the final answer.”
The Vatican Observatory: At the Intersection of Faith and Science
(950L)
By Michelle Feder, adapted by Newsela
When Rome gets too hot in the summer, the pope heads for the hills. The Alban Hills
outside of Rome, overlooking scenic Lake Albano, are home to Castel Gandolfo, the pope’s
vacation home.
Castel Gandolfo is a sixteenth century monastery that sits on a high ridge, a perfect spot to
view and reflect on the heavens. It is the main headquarters of the Vatican Observatory, one
of the oldest astronomical institutes in the world. The observatory is run by the Catholic
Church.
The pope’s astronomers have been using the observatory to study the night sky since 1891.
They have used one of the world’s oldest telescopes and the scientific method to try to
answer the fundamental questions of life, the Universe, and everything: How did the
Universe begin? What is our place in it?
For more than a century, this research center has been bridging religion and science. Castel
Gandolfo has a museum of meteorites. Its two large libraries contain more than 22,000
volumes, including historic works by Copernicus, Galileo, Newton, and Kepler. Every
summer, the astronomers at the observatory update the pope on their work.
“Science is an attempt to explain natural events by natural causes,” says Father George
Coyne, who directed the observatory. “The Church has a serious interest in understanding
the Universe and everything in it.”
In his view, “True science, good science, does not conflict with religious belief.”
A history of controversy
Today, popes support astronomy. But in the past, the relationship was not always so
smooth.
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In the 1600s, Italian astronomer Galileo Galilei challenged the teachings of the past.
Galileo observed the sky and concluded that the Sun was the center of our Solar System.
But the Catholic Church backed the Earth-centered, geocentric teachings of Aristotle and
Ptolemy. It did not accept these new ideas.
The Church was already dealing with the Reformation. The Reformation was a movement
that challenged the authority of the pope and the Catholic Church in Rome.
In 1542, the Church began the Inquisition, an organization that made decisions on questions
of morality and faith.
The Inquisition found Galileo’s writings about the Earth revolving around the Sun heretical
and incorrect. They banned his ideas and placed him under a life sentence of house arrest.
He died in 1642, still in confinement.
Since Galileo’s time though, the Church has expressed an interest in astronomical research.
Popes founded three different observatories in the eighteenth and nineteenth centuries.
Vatican astronomers made a major breakthrough in the mid-nineteenth century. Father
Angelo Secchi was the first to classify stars according to their spectra, the color of light they
give off. Modern spectroscopy is very important in astronomy today.
Advances in research
These days the telescopes at Castel Gandolfo are rarely used for astronomical research.
They are reserved for visiting groups and summer-school students. All serious study is
performed using other telescopes around the world, mainly in Arizona.
The Vatican set up an observatory in Tucson, Arizona, in 1981 after viewing conditions
around Rome got worse. The skies above Arizona are particularly dark and clear, making it
a perfect place for an observatory.
In 1993, the observatory finished building a state-of-the-art telescope. The Vatican
Advanced Technology Telescope has optical mirrors that are cutting edge.
“We are priests and religious men, but we also are scientists. Astronomy is our main service
to the Church,” said observatory director Jose G. Funes.
The Church reconsiders Galileo
The subject of Galileo has remained a tricky one for the Church throughout the years. In
1992, Pope John Paul II expressed regret at the way Galileo had been treated.
Later, in an official letter, he called for a balance between faith and reason: “Faith and
reason are like two wings on which the human spirit rises to the contemplation of truth.”
But the balance between faith and reason is sometimes difficult for popes to manage.
Pope Benedict XVI was criticized in 2008 for saying the Church’s verdict against Galileo had
been “rational and just.”
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95
“Galileo was a devout Catholic and was not trying to start a conflict between science and
religion,” writes Rachel Hilliam in a book on Galileo.
The Vatican Observatory: At the Intersection of Faith and Science (720L)
By Michelle Feder, adapted by Newsela
The pope’s vacation home is Castel Gandolfo, outside Rome. This quiet monastery sits on a
hill. It is a perfect place to look at and think about the sky.
Castel Gandolfo is also home to the Vatican Observatory. This observatory is one of the
oldest in the world. It is run by the Catholic Church. Since 1891, the pope’s astronomers
have been using the observatory to study the night sky. They have one of the oldest
telescopes in the world.
They hope to use science to answer a question that occurs to all people: How did the
Universe begin? What is our place in it?
The Vatican Observatory has been bridging religion and science for more than 100 years. Its
library holds more than 22,000 books. It includes historic works by Copernicus, Galileo,
Newton, and Kepler. Every summer, the astronomers at the observatory update the pope on
their work.
“The Church has a serious interest in understanding the Universe and everything in it,” said
Father George Coyne. Father Coyne used to run the Observatory.
In his view, “True science, good science, does not conflict with religious belief.”
A history of controversy
Today, the Catholic Church supports astronomy. But in the past, this was not always true. In
the 1600s, Italian astronomer Galileo Galilei challenged the teachings of the past. Galileo
observed the sky. He concluded that the Sun was the center of our Solar System.
But the Church supported the Earth-centric views of Ptolemy and Aristotle. It did not accept
Galileo’s new ideas.
In 1542, the Church began the Inquisition. Authorities in the Church investigated religious
questions. The Inquisition found Galileo’s writings about the Earth revolving around the Sun
incorrect. They banned his ideas. Galileo himself was punished with house arrest. He died in
1642, still not allowed to leave his house.
Since then though, the Church has supported astronomy. Popes set up three different
observatories in the 1700s and 1800s.
Vatican astronomers made a major breakthrough in the mid-1800s. Father Angelo Secchi
was the first to sort stars based on their spectra. The spectra were determined by the color
of light they give off. Modern spectroscopy is very important in astronomy today.
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Moving to Arizona
Today, the telescopes at Castel Gandolfo are rarely used for astronomical research. They
are usually used by visiting groups or students. The Vatican’s serious research now takes
place in Arizona.
Eventually, the skies around Rome became too bright. The Vatican set up an observatory in
Arizona. The skies there are very dark and clear. It's a perfect place for stargazing. The
Vatican’s telescope there is cutting-edge.
“We are priests and religious men, but we also are scientists. Astronomy is our main service
to the Church,” said observatory director Jose G. Funes.
The Church reconsiders Galileo
Even today, the subject of Galileo is tricky for the Church. In 1992, Pope John Paul II
showed regret for the way Galileo had been treated. Later, he called for a balance between
faith and reason. “Faith and reason are like two wings on which the human spirit rises to the
contemplation of truth,” he wrote in a letter.
But the balance between faith and reason is sometimes difficult for popes.
Pope Benedict XVI said in 2008 that the Church’s decision against Galileo made sense.
Many did not welcome his remarks.
Rachel Hilliam authored a book on Galileo. She wrote that Galileo never turned away from
the Catholic faith. He was "not trying to start a conflict between science and religion,” she
wrote. “He believed that the Bible was there to instruct people in how to get to heaven and
was not meant to be a scientific book explaining how the Universe worked.”
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