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240 BCE
Earth's Axis
Eratosthenes saw that the heavens seemed to rotate once a day around Earth. The axis of rotation formed an imaginary line from the North Pole to the South Pole through Earth’s center. Eratosthenes calculated the tilt of Earth’s axis relative to the plane of its equator with good accuracy. This is important because it gave us good idea about the earth's axis and rotation -
141
Model of the Universe
Ptolemy's mathematical model of the universe had a profound influence on medieval astronomy in the Islamic world and Europe -
1512
Copernicus
Copernicus wrote Commentariolus, or the Little Commentary, which is a little pamphlet that described that the earth is a planet that travels around the sun. Because the Church at the time believed the earth is the center of the universe, Copernicus only handed out his pamphlet to friends. This is important because it challenged the Church and was a major scientific work that was correct as well. -
Nov 11, 1572
Cassiopeia discovery
Tycho discovered a "new star" in the constellation Cassiopeia. He studied it for signs of motion relative to the background stars but found none, surmising that the star had to lie beyond the moon's orbit but it was actually a type 1 supernova. -
Kepler's Laws
This is the day the third law was written but by then the other two had been done. these laws are a basis for the laws of gravity and our understanding of it. -
Sir Isaac Newton Laws of Motion
In 1684 a scientist urged Newton to write about how a planet moved in a certain orbit. His work turned into a 3-volume book known as Principia. Published in 1687, this work details the 3 laws of motion and the law of universal gravitation. This is important because it gave us a better understanding of gravity and motion which are the basis for many scientific discoveries and experiments today, -
Theory of Relativity
Einstein finished the theory of relativity which is important because it is the basis of space travel and understanding space.
