Download Early Astronomers: Ptolemy, Aristotle, Copernicus, and Galileo

Early Astronomers: Ptolemy, Aristotle, Copernicus, and Galileo
By Virginia Johnson, CRRL Staff
http://www.kidspoint.org/columns2.asp?column_id=1078&column_type=homework
You know, because you've been told, that the Earth revolves around the Sun. You
also probably know that planets other than our own have moons, and the way to test
to see whether or not something is true is by experimenting. Thousands of years
ago, these things were not widely known. The heavens above were anyone's guess,
and the way things were was just the way the gods had made them. It was felt there
was no need to truly understand them or put them in any kind of order.
The Greek scholars changed much of that. They were famous for their schools of
higher knowledge, which were rather different than ours. Students would gather
around a teacher, perhaps in a beautiful grove, and ask questions and discuss
among themselves what might be the answers and the best ways to figure out those
answers. Many of today's colleges still aspire to this way of learning.
Ptolemy
Ptolemy was an astronomer and mathmatician. He believed that the Earth was the
center of the Universe. The word for earth in Greek is geo, so we call this idea a
"geocentric" theory. Even starting with this incorrect theory, he was able to combine
what he saw of the stars' movements with mathematics, especially geometry, to
predict the movements of the planets. His famous work was called the Almagesti. In
order to make his predictions true, he worked out that the planets must move in
epicycles, smaller circles, and the Earth itself moved along an equant. None of this
was true, but it made the math work for his predictions. This flawed view of the
Universe was accepted for many centuries.
Aristotle
He is sometimes called the grandfather of science. He studied under the great
philosopher Plato and later started his own school, the Lyceum at Athens. He, too,
believed in a geocentric Universe and that the planets and stars were perfect spheres
though Earth itself was not. He further thought that the movements of the planets
and stars must be circular since they were perfect and if the motions were circular,
then they could go on forever. Today, we know that none of this is the case, but
Aristotle was so respected that these wrong answers were taught for a very long
time. Aristotle, outside of astronomy, was a champion observer. He was one of the
first to study plants, animals, and people in a scientific way, and he did believe in
experimenting whenever possible and developed logical ways of thinking. This is a
critical legacy for all the scientists who followed after him.
Copernicus
Well over a thousand years later, Nicolaus Copernicus came up with a radical way of
looking at the Universe. His heliocentric system put the Sun (helio) at the center of
our system. He was not the first to have this theory. Earlier starwatchers had
believed the same, but it was Copernicus who brought it to the world of the
Renaissance and used his own observations of the movements of the planets to back
up his idea. His ideas, including the revealation that the Earth rotates on its axis,
were too different for most of the scholars of his time to accept. They used only
parts of his theory. Those who did study his work intact often did so in secret. They
were called Copernicans.
Galileo
Born in Pisa, Italy approximately 100 years after Copernicus, Galileo became a
brilliant student with an amazing genius for invention and observation. He had his
own ideas on how motion really worked, as opposed to what Aristotle had taught,
and devised a telescope that could enlarge objects up to 20 times. He was able to
use this telescope to prove the truth of the Copernican system of heliocentrism. He
published his observations which went against the established teaching of the
Church. He was brought to trial and, although he made a confession of wrong-doing,
he was still imprisoned for life. But it was too late to lock away the knowledge that
Galileo shared. Other scientists, including Sir Isaac Newton and Johannes Kepler,
seized its importance and were able to learn even more about the ways of the world
and the heavens beyond.
These early scientists' legacy continues to this day. As time goes on, we use our
instruments, science, math, reasoning, and creativity to learn more about the
secrets of the Universe. In this way, we are directly linked to the astronomers of
centuries ago who gave us direction to discover more about the dances of the
planets and the nature of the stars.
In the Library and on the Web
Discovery of the Solar System
http://www.phy6.org/stargaze/Ssolsys.htm
This site from NASA follows the development of ideas about the solar system
from Ptolemy to Copernicus to Galileo.
Makers of Science by Michael Allaby & Derek Gjertsen.
Volume one of this reference set has information on Aristotle, Copernicus, and
Galileo. The books are available to use at the Porter, Salem Church, Snow,
Cooper, and Montross branches.
Articles on Ptolemy, Copernicus, Galileo, and Aristotle can be found in our online
databases, The New Book of Popular Science and AccessScience@McGraw-Hill.
Aristotle
Aristotle and Scientific Thought by Steve Parker.
This book captures the life and times of Aristotle, the ancient Greek
philosopher who studied a wide range of subjects and helped shape early
scientific beliefs. Includes full-color paintings, drawings, and photos.
Aristotle (384–322 BC)
http://www.museum.vic.gov.au/scidiscovery/scientists/aristotle.asp
A quick discussion of Aristotle's accomplishments. Has a full-color depiction of
Aristotle and a diagram of his cosmology from an old source. From Museum
Victoria, Australia.
Copernicus
Dance of the Planets: The Universe of Nicolaus Copernicus by Nancy Veglahn
In a time when ground-breaking scientific thought was viewed with suspicion,
Nicolaus Copernicus continued his astronomical studies on the movement of
the planets. A short book (63 pages) that uses imagined dialogue and helpful
illustrations to make the story easier to understand.
The History News in Space by Michael Johnstone.
Uses a newspaper format to take a look at developments that led from the
ideas of Copernicus and other early scientists to the technological advances
that enabled man to venture to the moon and beyond.
Nicolaus Copernicus: Making the Earth a Planet
This eBook from Oxford University Press is targeted to high school students
and above. Click here for information on accessing our eBook collection.
Galileo
Famous Experiments and How to Repeat Them by Brent Filson.
Looks at the experiments of Archimedes, Galileo, Newton, Fleming, and
others, whose scientific efforts gave new ideas to mankind. Includes
instructions for the reader to perform the same experiments.
Galileo by Leonard Everett Fisher.
A short (30 pages) picture book biography of the talented scientist,
appropriate for sharing with a class. It touches on his inventions and
discoveries, his persecution by the Church authorities, and the eventual
reinstatement of his ideas.
Galileo by Douglas McTavish.
Tells of Galileo's life and how his discoveries went against the accepted beliefs
of his time.
Starry Messenger: A Book Depicting the Life of a Famous Scientist, Mathematician,
Astronomer, Philosopher, Physicist, Galileo Galilei created and illustrated by Peter
Sis.
A beautiful retelling, in picture book format, of Galileo's story which can be
used with both younger and older audiences.
The Galileo Project
http://es.rice.edu/ES/humsoc/Galileo/
A hypertext source of information on the life and work of Galileo Galilei
(1564-1642) and the science of his time. Includes a biography, letters from
his daughter, and a tour of his home. From Rice University.
Galileo's Battle for the Heavens
http://www.pbs.org/wgbh/nova/galileo/
A timeline of his life, articles on his place in science and his telescope, his
mistakes on predicting the tides, a teachers' guide, and interactives on his
experiments with falling objects, projectiles, inclined planes, and pendulums.
Ptolemy
Ptolemy: Roman Scholar Claudius Ptolemaeus
http://geography.about.com/od/historyofgeography/a/ptolemy.htm
A bit on Ptolemy's life and more about his accomplishments.
Ptolemy, the Man
http://nineplanets.org/psc/theman.html
An overview of Ptolemy's achievements and links to biographical information.
Ptolemy's World
http://bell.lib.umn.edu/map/PTO/indexpt.html
Lots of illustrations of Ptolemy's geography, a note on his principle of
simplicity, and links to his texts.