ASTR 101 Lecture Notes - Lecture 11: Antikythera Mechanism, Alfonso X Of Castile, Deferent And Epicycle

• School: Queen's University
• Department: Physics, Engineering Physics and Astronomy
• Course: ASTR 101
• Professor: David Alan Hanes

Document Summary

Ptolemy believed planets went around in epicycles which also orbited the earth, causing the retrograde motion. We overtake outer planers o the inside track (larger planets appear to go backwards because we are moving quickly around the sun; perspective) Venus and mercury never appear in the midnight sky; usually close to sun. Ptolemy gave venus and mercury epicycles as well; assumed that centres of their epicycle were always directly between earth and sun. King alfonso x said believed it should be simpler. Mechanical machine predicted the motions of sun, moon and planets; sophisticated for the time ( rst century bc) Displayed how planets moved in retrograde motion; the rotation of the moon. Demonstrate that other planets (in particular, venus and mercury) orbit the sun rather than orbiting us. Detect parallax of nearby stars, it would prove earth is moving through space. Copernicus had idea that we were orbiting the sun.