ASTRONOMERS AND HISTORY

ARISTOTLE

• He lived 384 -322 B.C
• Proved earth was a sphere.
• Earths shadow on the moon was circular.

ARISTARCHUS

• Lived 310-230 B.C
• Proved that earth rotates on its axis
• Earth revolves around the sun

PTOLEMY

• 85-165 A.D
• Positions of the planets
• Planets obiting in spheres

NICHOLAS COPERNICUS

• 1473-1543
• Earth is not the center of the universe
• Planets orbited instead of sun

JOHANENES KEPLER

• 1571-1630
• How long it takes to orbit relates to how far away it is.
• Orbits of planets are eliptical to sun at one focus

GALILEO GALILEI

• 1564-1642
• Moon had an uneven surface
• Milky way is made up of lots of seperate stars

ISAAC NEWTON

• 1643-1727
• Law of gravity
• Laws of motion

EDWIN HUBBLE

• 1889-1953
• Universe was expanding
• Andromeda nebula is a galaxy external to the milky way