NATS 1740 Lecture Notes - Lecture 7: Retrograde And Prograde Motion, Naked Eyes, Scientific Method

• School: York University
• Department: Natural Science
• Course: NATS 1740
• Professor: Michael De Robertis, Alireza Rafiee

Document Summary

They only depended on dark night, there was no artificial light at that time. *planets known in ancient times: mercury (close to the sun, venus (bright, visible, mars, jupiter, saturn. Everything rise in east and set west, each night stars rise 4 minutes earlier => they appear daily. Planets move west to east from night to night (most of the year) => prograde motion. Some planets move east to west for a while => retrograde motion. Greeks thought earth is the centre of the universe => complicated to explain planetary motion. However, the fact that sun is the centre of the universe. Apparent retrograde motion: easier to explain because we lap another planet (the ancients reject this because of some reasons) They were not able to see stellar parallax (a change in position of stars based on the observer vision or postion) => they thought the stars cannot be far away.