ATMOSPHERE

ARISTOTLE

• Greek philosopher
• Thought earth went around sun
• Parallax

ARISTARCHUS

• Heliocentric model
• Attempted to measure the relative distance to the moon and sun
• Thought stars and planets were perfect spheres

PTOLEMY

• Celestial body traveled at a constant speed in a perfect circle
• "Wheels on wheels" system fit the observation
• Allowed prediction of the motion of planets into the future

COPERNICUS

• Used "wheels on wheels" system
• Thought Ptolemy's solar system was too complicated
• Model showed first steps of developing the modern solar system

KEPLER

• Realized planetary motion wasn't exactly circular
• Formulated 3 principles known as keplers laws

GALILEO

• Used scientific method
• Used more powerful telescope
• Observed the motion of the planets