ASTR 101 Lecture Notes - Lecture 5: De Revolutionibus Orbium Coelestium, Retrograde And Prograde Motion, Deferent And Epicycle
Document Summary
Retrograde motion challenged the simplicity of the geocentric model. The heliocentric model rather easily explained retrograde motion due to the. Earth overtaking planets that are farther from the sun. The lack of observable parallactic motion was a serious criticism of the heliocentric model. However, the motion is just so small because the stars are so far away, which early astronomers could not comprehend. The heliocentric model suggests that earth is moving really fast through space (almost 500 km/s) Early astronomers criticized the model because they assumed humans would be able to feel the movement of the earth. Despite these issues, the ptolemaic model was in crisis in the middle of the. Increasingly accurate observations forced renaissance astronomers to add complexities to the geocentric model to make it match what the planets appeared to be doing. In the early 16th century, astronomers such as copernicus began to look for a way to return to a simpler model.
