Ptolemy鈥檚 theory and Copernicus鈥?theory both explained the retrograde motion of planets. Explain a) what is r?

Ptolemy鈥檚 theory and Copernicus鈥?theory both explained the retrograde motion of planets. Explain a) what is retrograde motion b) the differences between the two theories and how they explained why retrograde motion occurred in each of these theories (+4pts)Ptolemy鈥檚 theory and Copernicus鈥?theory both explained the retrograde motion of planets. Explain a) what is r?Retrograde motion in this context is the apparent reversal of a planet's path among the background constellations during a brief period of time. The outer planets of the solar system appear to do this when opposite the sun in the sky.





Ptolemy had made it complicated with the concept of epicyclic motion being the actual path of planets in very funky orbits around the Earth. He ATTEMPTED to explain the kinematics of it...as in made a mathematical description of it...but this mentioned nothing of the cause of the motion.





Copernicus put the sun at the center instead...and put each planet in a simple orbit around the sun, and claimed that the apparent retrograde of some planets is nothing more than when Earth passes said planet while rounding the inside track on Earth's own orbit around the sun.





It was later discovered by Galileo that Jupiter had its own set of moons, as in that some parts of the universe were Jovicentric, and that it wasn't all geocentric as Aristotle and Ptolomy had thought. As in, nothing is necessarily special about the Earth. This discovery of a Jovicentric system of moons is considered to be the "nail in the coffin" for the geocentric model...and from then on, it was understood that all neighboring bodies of Earth were in orbits around the sun...and that the moon orbited the sun along with Earth, also orbiting Earth.



Newton's law of universal gravitation eventually became the explaination of the "why".