Astronomy 1021 Lecture Notes - Lecture 5: Nicolaus Copernicus, Deferent And Epicycle

• School: Western University
• Department: Astronomy
• Course: Astronomy 1021
• Professor: Sarah Gallagher

Document Summary

Proposed a heliocentric universe (sun centered) rather than a geocentric universe (earth centered) It naturally explains why mercury and venus never travel far from the sun. It reproduces much better than observed change in brightness of planets, as consequence of changing distance from the earth. Its provides a natural explanation for the seasons. Its provides a natural explanation of retrograde motions without relying on epicycles. Copernicus still assumed that the motion occurs in circles. Since true orbits are not circles, he needed to offset toe centres of circles and add more circles to the model. In essence, his model was no more accurate that the ptolemaic model. Compiled the most accurate naked eye observations ever over a period of 3 decades. Observed a new star (nova) in 1572 measured its parallax, and found it was much further away than the moon. Similarly, found that a comet was much further away than the moon.