Ohh, retrograde motion came up in last week's cosmology exam:

Explaining retrograde motion requires us to make tweaks to the Copernican model. The Copernican model ditched the commonly held view that the earth was at the center of everything and replaced it with this:

Which solved unbelievably complicated paths that some planets took on the earlier model. The copernican model however was not perfect, there were 3 problems:

1-Some stars didn't appear to move at all throughout the seasons.

2-Retrograde motion

3-Some planets positions didn't quite match up the predictions

The first problem was easy enough to solve, those stars are just unbelievably far away so there is negligible parallax.

The second and third however required the works on Johannes Kepler and Issac Newton. Kepler discovered 3 laws for planetary motion, they were:

1-Planets move in ellipses

2-Areas A and B are the same

3-The square of the period is inversely proportional to the cube of the distance between the star and the semi-mayor axis of the elliptical path

With Newton we get 2 incredibly important equations:

F=ma(Newtons second law of motion)

F=GmM/r^2(Newtons law of gravitation

F/m=a

therefore

a=GM/r^2

What the mathematics of this say is that as a planet gets closer to the sun, it will travel faster around it. Because a planet closer to the sun will be accelerating, it means that at one point the planet will become faster that a planet further away and can actually overtake it. This is why the planet will slow down, stop, go backwards and then start going forwards again.

The sun rises roughly from the east and set west(changes slightly depending on the season), If the sun actually rose from the west then it would be a huge event. Really the only think I can think of which could cause this to happen is some sort of huge meteor hitting earth in a certain angle.