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2000 BCE
Aristarchus of samos
4 or 3 century Aristarchus suggested that the earth revolved around the sun -
2000 BCE
The greek astronomy Hiparchus
classified the stars according to their apparent brightness -
2000 BCE
Ptolemy
suggested a geocentric astronomic model . according yo him the sun , the moon and the five known plaqnets mercury Venus Mars Jupiter and Saturn -
480 BCE
thales
The ancient Greeks inherited astronomical records from the Babylonians and applied the data to construct a cosmological framework. Data was not just used for practical goals, such as navigation, but also to think of new experiments = natural philosopher. Thales (~480 B.C.) used this data to predict eclipses. -
220 BCE
erasthrotenes
Eratosthenes (220 B.C.) - The early Greeks knew the Earth was a sphere based on the shadow of Earth on the Moon during lunar eclipses. Eratosthenes proceeded to use this information to measure circumference of Earth in the following manner; he knew that on a certain date that a stick placed in the ground at Syene cast no shadow. Whereas, a stick at Alexandria has a small shadow. Using simple ratios he showed the following: -
200
ptolemy2
The solution to retrograde motion was to use a system of circles on circles to explain the orbits of the planets called epicycles and deferents. The main orbit is the deferent, the smaller orbit is the epicycle. Although only one epicycle is shown in the figure below, over 28 were required to explain the actual orbits of the planets. -
500
phytagoras of samos
Most famous for his theorem, little is known of his actual work. He founded a school (some would call it a cult) of natural philosophy and mysticism that attracted many followers. The Pythagoreans lived by a strict regimen including vegetarianism, silence for the first 5 years of membership, and anonymity with respect to personal accomplishments (so that it is difficult to know what to ascribe to Pythagoras as opposed to his followers). -
Oct 4, 1500
alexandri burns
Alexandria burns, Roman culture collapses, Dark Ages... but the Roman Catholic Church absorbs Aristotle's scientific methods and Ptolemy's model into its own doctrine. Thus, preserving the scientific method and Ptolemy's Solar System until the... The Renaissance, where new ideas were more important than dogma. -
Sep 19, 1543
Copernicus
published his heliocentric model according to wich the planets revolved around the sun -
Kepler
Kepler (1600's) a student of Tycho who used Brahe's database to formulate the Laws of Planetary Motion which corrects the problems of epicycles in the heliocentric theory by using ellipses instead of circles for orbits of the planets. The formulation of a highly accurate system of determining the motions of all the planets marks the beginning of the clockwork Universe concept, and another paradigm shift in our philosophy of science. -
Galileo
used a telescope for the first time to observe the night sky .this was the birtyh of modern astronomy -
Tyco Brahe
carried out very detailed observation of the planets .Kepler deduced his famous planatary laws following Brahes observation -
Isaac newton
build the first telescope using mirrors insttead of lenses -
Galileo
(1620's) developed laws of motion (natural versus forced motion, rest versus uniform motion). Then, with a small refracting telescope (3-inches), destroyed the the idea of a "perfect", geocentric Universe with the following 5 discoveries: -
trip to mars
they are going to do a trip to mars to see if they are life on mars because they found water
