Astronomy

Ptolemy

150

Discovery: Geocentric Theory, a theory that Earth is in the center of the universe. He believed that planets moved in epicycles ( smaller circles) and Earth moved along an equant. His theory was incorrect. Significance: People believed this theory for about 800 years until it was discovered to be incorrect.

Nicolaus Copernicus

Jan 1, 1543

Discovery: Believed that the sun was in the center of the universe rather than the earth with the Earth and other planets circling around it. Significance: Changed how people thought, with the sun in the center rather than the Earth

Tyche Brahe

Jan 1, 1570

Discovery: Concluded that Earth is in the center of the universe and either Earth does not move, or that stars were to far away to calculate their parallax. Significance: Made people believe that Earth was the center of the universe, but was proven wrong many years later.

Johanne Kepler

Jan 1, 1600

Discovery: The law of planetary movement; Discovered that the planets went around the sun in elliptical orbit. Significance: He changed what Copernicus said by saying that planets moved around the sun in elliptical orbit rather than circular.

Galileo Galilei

Jan 1, 1632

Discovery: Four largest moons of Jupiter and Sun spots, which proved that the planets orbited around the sun and not the Earth. Significance: Proved that Earth was not in the center of the Universe.

Isaac Newton

Jan 1, 1687

Discovery: Discovered theories that connected other theories together like his theory of gravity. Another of his theories was the theory of movement, which stated that an object will not move unless something causes it to move. Significance: This allowed him to calculate the mass of each planet.