NATS 1880 Lecture Notes - Lecture 2: Retrograde And Prograde Motion, Geocentric Model, Diurnal Motion

• School: York University
• Department: Natural Science
• Course: NATS 1880
• Professor: Michael De Robertis

Document Summary

Consider the motion in the sky (diurnal motion: sky trails . Why so important: ancient peoples all over the world observed with great accuracy the motion of the. Sun, moon, planets and stars: the noted the regularity of motions such as the sun rising in the east and setting in the west. Tuesday - mars, wednesday - mercury, thursday - jupiter, friday - venus, Retrograde motion - an observation to challenge the geocentric theory (very puzzling) Heliocentric model (sun centered view) introduced by aristarchus. A simpler idea requiring less complex geometry to explain the retrograde motion of the planets. Logic dictated 2 options; either the stars were ver far away or in truth the earth was the centre of the universe. Annual (stellar) parallax (related to the apparent angular shift of the star: if you can detect this than you can confirm the earth moves around the sun.