Untitled Slide

ARISTOTLE

• Thought the solar system was geocentric
• Thought all planets went around the earth & the earth did not move
• He said if the earth were to move parallax would happen

ARISTARCHUS

• Came up with the heliocentric solar system model
• His model showed the earth and other planets orbiting the sun
• Made attempts to measure distance to the moon and sun (big contribution to science)

PTOLEMY

• Wrote the Almagest book based on his observations of planets
• Made a detailed geocentric model that was used for 14 centuries by astronomers
• Believed the celestials body moved in a perfect circle at a consistent speed
• Came up with the "wheels-on-wheels" concept that says planets move in small circles that movie in larger circles around earth

COPERNICUS

• Made the 1st detailed heliocentric model of the solar system based off Aristarchus
• Used the "wheels-on-wheels" system and made hit model more realistic than ptolemy's
• His model is generally seen as the 1st step to understanding the solar system

KEPLER

• Realized perfect circular rotations of the planets wasn't realistic
• Found that instead of circular paths there were ellipses
• Formulated 3 laws (Kepler's laws)
• 1) planetary orbits are ellipses with the sun at one focus
• 2) planets move faster in their orbits when closer to the sun
• 3) this law relates the distance of a planet from the sun to the time it takes for one full orbit to take place

GALILEO

• Made advancements to telescopes
• Used his more powerful telescope to view celestial objects
• He viewed the moons which are now named the Galilean satellites
• Gave support to the heliocentric model like proving the earth wasn't the only thing that could be orbited
• Discovered that Venus went through phases similar to the moons