1. Greek Astronomy Philosophers: Aristarchus

2. Aristarchus of Samos was an ancient Greek astronomer and mathematician who presented the first known model that placed the Sun at the center of the known universe with the Earth revolving around it (see Solar system).

3. Aristarchus (3rd Century B.C)
Sun is the center of the universe
Heliocentric model
First to measure the distance to the sun and moon

4. REVOLUTION is the cycle in which a planet orbits the sun (one year)
Aristarchus
REVOLUTION is the cycle in which a planet orbits the sun (one year)
ROTATION is the cycle of a planet spinning on its axis; day to night (one day)

5. Aristarchus of Samos was an ancient Greek astronomer and mathematician who presented the first known model that placed the Sun at the center of the known universe with the Earth revolving around it.