ASTR 100Lgx Lecture Notes - Lecture 4: De Revolutionibus Orbium Coelestium, Deferent And Epicycle, Geocentric Model
Document Summary
Also aberration of starlight discovered by james bradley. Aristarchus of samos said earth rotated the sun 300 bc. You have to make a correction due to the finite speed of incoming light. Made an island observatory on island of rhodes. Discovered the precession of the earth"s spin axis. We know the earth rotates due to galileo"s discovery of stellar parallax 1838. Hipparchus was the greatest pre-christian astronomer, 150 bc. Five planets visible to the eye: mercury, venus, mars, jupiter, saturn. Planets sometimes move westward against the stars, making the greeks to fancy them godly. Criteria for scientific models: must fit the data, must make predictions that can be tested with observations, need a new model is the old model fails predictions, simplest possible model, cut down to ockham"s razor. Ptolemy"s model wasn"t proven wrong for 1000 years. The arabs translated some greek documents before burning down alexandria. Greeks explained this with epicycles, mini circles along the big orbit (deferent)
