* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download history of astro outline 2014
Astrophotography wikipedia , lookup
History of Mars observation wikipedia , lookup
Kepler (spacecraft) wikipedia , lookup
Galileo affair wikipedia , lookup
Physical cosmology wikipedia , lookup
Fine-tuned Universe wikipedia , lookup
Spitzer Space Telescope wikipedia , lookup
Planets beyond Neptune wikipedia , lookup
Rare Earth hypothesis wikipedia , lookup
Non-standard cosmology wikipedia , lookup
De revolutionibus orbium coelestium wikipedia , lookup
Chinese astronomy wikipedia , lookup
International Ultraviolet Explorer wikipedia , lookup
IAU definition of planet wikipedia , lookup
Astronomical unit wikipedia , lookup
Exploration of Io wikipedia , lookup
Formation and evolution of the Solar System wikipedia , lookup
Planetary habitability wikipedia , lookup
History of Solar System formation and evolution hypotheses wikipedia , lookup
Theoretical astronomy wikipedia , lookup
Celestial spheres wikipedia , lookup
International Year of Astronomy wikipedia , lookup
Definition of planet wikipedia , lookup
Astrobiology wikipedia , lookup
Astronomy in the medieval Islamic world wikipedia , lookup
Planets in astrology wikipedia , lookup
Patronage in astronomy wikipedia , lookup
Galilean moons wikipedia , lookup
Satellite system (astronomy) wikipedia , lookup
Extraterrestrial life wikipedia , lookup
Observational astronomy wikipedia , lookup
Dialogue Concerning the Two Chief World Systems wikipedia , lookup
History of astronomy wikipedia , lookup
Ancient Greek astronomy wikipedia , lookup
Copernican heliocentrism wikipedia , lookup
HISTORY OF ASTRONOMY OUTLINE Beginnings 3000 BC Ancient Babylonians develop number system based on 60 (led to time-keeping and angular measurements) and 12month calendar. Ancient Egyptians separated a day-night period into 24 separate hours and the year into 365 days 2150 BC Stonehenge—entrance stones are lined up so it would be possible to see the sunrise on the summer solstice. Likely that Neolithic tribes were responsible for construction. 2136 BC Ancient Chinese—recorded observations of the night sky; eclipses and comets and supernovae were observed. These peoples actively practiced astronomy by attempting to understand and quantify their surroundings. Most cultures developed a geocentric view of the universe, based upon the apparent east to west motion of the stars, Sun and moon. Pythagoras and the Ancient Greeks 550 BC Pythagoras of Samos began using mathematics to describe natural phenomena. 350 BC Aristotle supported the geocentric view and he had influence. He also had views about the cosmos and considered the Earth to be spherical, based upon observations during lunar eclipses. Aristotle’s other views are worth noting: o Four elements (Earth, fire, air and water) o Five known planets were fixed to crystalline spheres encased in a celestial sphere containing all stars. o The heavenly objects were composed of a fifth element called quintessence. o Each of the spheres revolved around the Earth in perfect circles. History of Astronomy Page 2 o Earth was subject to birth, decay and death (imperfection) while the heavens were pure, unblemished and unchanging (perfection). o Aristotle also believed that an object stays in motion because a force is constantly pushing it. o Inconsistencies were recognized by the Chinese, reported blemishes such as moving objects with tails (comets) and bright lights that appear and disappear (supernovae). Also, the sometimes backwards motion (retrograde motion) of planets Mars, Jupiter and Saturn was not explained by the geocentric view. 270 BC Aristarchus of Samos expressed a different point of view. He proposed a sun-centered universe (e.g., heliocentric). 200 BC Erathosthenes devised a method to measure the circumference of the Earth. 200 BC Hipparcus refined the geocentric model using epicycles. 125 AD Last of the great Greek astronomers, Ptolemy of Alexandria, Egypt expounded upon previous theories about the motion of the planets and firmly defended the geocentric model of the universe. Ptolemy’s work included: Claudius Ptolemy proposes an Earth-centered (geocentric) model of the universe in his work called Almagest. His work supported Aristotle’s geocentric view of the universe. To address the problem of retrograde motion of Mars, Jupiter and Saturn, Ptolemy used a complex system of epicycles. As the planet circled the Earth, it also had a mini-orbit around a point on the larger orbital circle. The solution used perfect circles. Understanding of astronomy increased as the usage of mathematics, direct observation and logical reason increased. History of Astronomy Page 3 From 1st Century AD to 16th Century AD Limited input from western world. Continued Middle Eastern input. No significant advances in understanding or technology to unglue the adherence to the geocentric model of the universe. Little progress was made until the 16th century. What was responsible for this 14-century gap (the Middle Ages)—a scientific lull lifted by the advancement of new technologies. The printing press: dissemination of knowledge through printed material became part of the public domain. The telescope: pushing the boundaries of our universe to new places. Subsequent observations led individuals to alter their understanding of the universe. Mathematics became a predictive tool, useful in explaining the orbits of the planets. Astronomical observations were used to develop theories. Baywatch and Jersey Shore (Just checking if you are reading) 16th Century AD (Renaissance) By the 1500’s, the geocentric model did not accurately predict the motion of the planets. Variations that seemed tiny in the 2nd century grew into significant deviations and greatly lessened the predictive ability of the geocentric model. This demanded an explanation. 1500 AD The geocentric view survived until the European renaissance in the 1500’s, when Nicolas Copernicus proposed a Suncentered (heliocentric) model of universe. His work supported Aristarchus’s heliocentric view of the universe. Copernicus was looking for a simpler model (Occam’s Razor). 1593 AD Copernicus had his heliocentric model published in his work called De Revolutionibus Orbium Coelestium. He died within days after receiving the first copy of its publication. History of Astronomy Page 4 In his work, Copernicus concluded the following: Mercurys and Venus, since they appear closest to the Sun, have orbits inside the Earth’s orbit. Mars, Jupiter and Saturn, since they appear high in the night sky, have orbits outside the Earth’s orbit. The configuration (or orbit) of each planet. The measurement of each planet’s sideral and synodic period. The calculated distance of each planet to the Sun. 1576 AD Danish king Frederick II built Tycho Brahe an astronomical observatory called Uraniborg. Brahe begins to catalog his observations of the stars and planets using devices that accurately measure position and angle of stars and planets as viewed with the unaided eye. 1600 AD At Uraniborg, Brahe made numerous observations and recorded the most accurate measurements of astronomical objects up to this time. Brahe used his observatory to measure the positions of astronomical objects for 21 years. Greatest collection of astronomical observations at the time. Johannes Kepler joined Tycho Brahe and gained access to Brahe’s entire volume of astronomical observations. He used these observations to deduce three laws concerning planetary orbits and proved that planetary orbits occur not in perfect circles, but in ellipses. Brahe had Kepler join him at Uraniborg in 1600, after reviewing Kepler’s mathematical predictions of the planetary orbits published earlier in 1596. Johannes Kepler solves the problem of the irregular orbits of the planets by showing that planets orbit in ellipses, not perfect circles. He establishes three laws to describe planetary motion. Kepler used Brahe’s comprehensive astronomical measurements to solve the puzzle. Kepler’s laws could only explain how the planets move, but not why. 1608 AD Hans Lippershey from the Netherlands invented the telescope. 1609 AD Galileo Galilei constructs a telescope and uses it to make a series of discoveries that contradicted the geocentric model, Aristotle and the Roman Catholic Church. History of Astronomy Page 5 About Galileo’s contributions: Galileo supports the heliocentric model with his observations Galileo used the telescope to make observations of the heavens. His observations supported the heliocentric view of the universe 1. Phases of Venus: Venus had phases just like the Moon (the change in the apparent size of Venus was related to the planet’s phase) 2. The orbit of Jupiter’s moons: Jupiter’s moons (Galileo observed the location of the four moons of Jupiter over time, and concluded that they are orbiting Jupiter because they move across from one side of the planet to the other). 3. Imperfections on the Moon’s surface: The Moon’s surface was irregular and crater-filled 4. Dark spots on the Sun: The Sun was observed to have dark spots These observations began to erode the notion of celestial perfection and provided support for the heliocentric view of the universe. Of course, Galileo’s view was in conflict with Aristotle and the Roman Catholic Church, who accepted only the geocentric view. Galileo had to recant his support of the heliocentric view and was placed under house arrest for the remainder of his life for “vehement suspicion of heresy.” (Without a good word put in by a friend with influence in the papal circles, Galileo might have had to endure the Inquisition’s notorious and, at that time, legal investigative process—torture, confession and, quite often, death.) Galileo’s observations provided support for the heliocentric model, but he was limited by life’s circumstances (house arrest and his health). 1687 AD Sir Isaac Newton publishes his major work on forces and gravity called Philosophiae Naturalis Principia Mathematica. 1704 AD Sir Issac Newton figures out the planets are moving under the influence of gravitational force, which supports Kepler’s findings. Newton created a mathematical description of how gravity behaved and determined it to be a universal force, meaning that all motion in the universe was governed by gravity. Newton publishes his experiments and theories about light and color called Optiks. He laid the groundwork for the understanding of the true nature of light, which is how the composition of the universe is determined.