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200
Ptolemy
Time Lived: 90AD-AD168 Ptolemy thought that the earth was the center of the universe and everything revolved around it. He also believed that the stars were attached to a crystal sphere that spun around the earth and that all the other planets traveled with spheres of their own too. Ptolemy also thought that each planet moves on a smaller sphere too—an epicycle. Ptolemy’s theory was considered valid for about 1,500 years until Galileo looked through a telescope into the heavens. -
Period: 200 to
Dates Scientists were Born
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Feb 19, 1473
Nicholas Copernicus
Life Span: 1473-1543 Copernicus was the first to propose the heliocentric theory. This idea first struck him when he was observing the patterns of Mars. He noticed sometimes Mars went forwards, other times it got slower or went backwards. Copernicus never proved this theory because he did not have the equipment (a telescope) to help him (telescopes were not yet invented). -
Feb 15, 1564
Galileo Galilei
Life Span: 1564-1642
Galileo was a strong believer in the heliocentric theory (copernicanism). Galileo wanted to build on Copernicus' idea of the heliocentric universe so he built a larger scale of a childrens toy called a telescope. Galileo made many discovery's using his telescope including Jupiter's moons, and studying the phases of planet Venus. After he convinced him self that Copernicus' theory was correct, the catholic church made him withdraw his support to this theory. -
Dec 27, 1571
Johannes Kepler
Life Span: 1571-1630
Kepler strongly supported the heliocentric side of the argument. Although his employer supported the geocentric side, his employer Tycho Brahe, admired his stubborness in his beliefs. He proposed the idea that the universe was shaped like 5 polygons. Click on the link below to see these polygons: http://www.hps.cam.ac.uk/starry/kepler2med.jpg -
