| A | B |
|---|
| geocentric | Earth centered Universe |
| heliocentric | Sun centered Universe |
| The Greeks | Believed the Earth was the center of the Universe |
| Ptolemy | Revised geocentric model; planets moved in little circles on bigger circles around the Earth |
| Nicolaus Copernicus | Developed the heliocentric model of the Universe |
| Galileo | Found evidence to support the heliocentric model |
| 4 moons of Jupiter and Venus's phases | Galileo's evidence that supports the heliocentric model |
| Tycho Brahe | Studied the sky for 20 years! |
| Johannes Kepler | Used Brahe's data and discovered the planet's orbits are elliptical |
| Issac Newton | Determined inertia and gravity keeps planets in their orbits |
