used as a calendar
Model of 27 nested spheres
divided the universe into the perfect heavens and the static earth. Uniform circular motion
Placed Earth away from the center of the perfect spheres
Added epicycles to account for retrograde motion.
written by Copernicus. Didn't account for varying speeds of planets or nonperfect circles
made very precise observations. disproved the perfect universe. believed everything orbited the sun which orbited the earth.
invented observational based science. wrote a dialogue of 2 chief world systems. supported the Copernican model.
used brahe's observations. discovered the non-uniform velocities of the elliptical paths of the planets. 1st to accurately predict planetary motions.