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Ptolemy "Perfects" geocentric model
In Ptolemy's model the planets moved on circles (epicycles) that moved on other circles (deferents). The model could accurately predict the positions of the planets. -
Nov 18, 1054
Chinese record a supernova
This supernova was the supernova that created the crab nebula -
Nov 18, 1330
Impetues Theory of Motion
Jean Burdian develops this theory. Buridan's theory of motion was remarkable in that it contradicted the established ideas of Aristotle. -
Nov 18, 1420
One of the First Observatory's is built
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Nov 18, 1543
De Revolutionibus
Copernicus's description of his heliocentric model of the solar system, was published two months before his death -
Galileo begins experiments with falling and rolling bodies.
Galileo's experiments led him to conclude that once something is set in motion it will remain in motion unless something stops it. This contradicted earlier ideas that said only rest was a natural state. -
Galileo observes Moon.
Galileo found that the Moon had mountains, valleys, and plains like the Earth. He called the dark regions of the Moon maria, the Latin word for seas -
Kepler discovers laws of planetary motion.
Working with Tycho's observations, Kepler discovers the shapes of planetary orbits, how the speed of a planet varies as it orbits the Sun, and the relationship between orbital distance and orbital period -
Period: to
Newton discovers law of universal gravitation.
When Cambridge University was closed by the plague, Newton spent most of the next two years at his family farm. During this period he made fundamental discoveries in optics, discovered the law of universal gravitation, and invented differential and integral calculus -
William Herschel discovers speed and direction of Sun's motion
Herschel analyzed the motions of seven bright stars and showed that part of their motions was due to the motion of the Sun through space. -
Friedrich Bessel, Wilhelm Struve, Thomas Henderson measure the distances of stars
Bessel, Struve, and Henderson, working independently, almost simultaneously measured the parallaxes, and hence the distances, of nearby stars. These were the first measurements, rather than estimates, of stellar distances