Summary
What do we really see in the sky?
- Sun, Moon, Stars appear to rotates around the earth
- Just from observing the sun from the earth one cannot distinguish between descriptions with the earth at the center or the sun at the center!
- Which explanation is simpler? More useful?
Problem of the Planets
- The strange motion of the planets is an esoteric effect of no practical consequence for people --- yet it is crucial in the story of science competing world views of enormous philosophical and practical importance
- Astrology treats the motion as somehow related to life on earth - leads to fortune telling, horoscopes, ….
- Astronomy searches for explanations in simple laws - Leads to new science - Kepler’s Laws - crucial for Newton’s theory - Next