Retrograde Motion !!! Is it gonna happen to earth ? When?

Answer 1

Yes and no. There are two definitions of retrograde.

One definition just means actually orbiting the other way. That will never happen to Earth or any of the other planets in our solar system.

The other definition is the apparent switching direction in the sky of all the planets as seen from Earth during the year. This motion is just an illusion caused by the different speeds that each planet orbits the Sun. Earth orbits the Sun faster than Mars does, so when Earth catches up to and passes Mars, Mars seems to move backwards in the sky. It is much like passing a car on the road. The other car is going 50 and you are going 60, so it may seem like the other car is going backwards at 10 as you pass it. In this sense, Earth goes retrograde frequently, as seen from Venus.

Answer 2

Yes its going to happen, yes it has already happened, and for all i know it could be happening right now. All retrograde motion is is the optical illusion that a object appears to stop, then reverse its orbit, then stop again and continue its regular course. It can be viewed from earth when earth passes mars on its orbit around the sun(because earth orbits the sun faster than mars). But if you were on venus when it passes earth, earth would appear to move backwards i.e. retrograde motion

Answer 3

There are a number of moons that orbit their planets retrograde. None of the known planets do. I know of no reason why the Earth reverses its orbit.

Are you sure you know exactly what retrograde motion is?

See here: http://en.wikipedia.org/wiki/Retrograde_orbit

Answer 4

Technicly Earth has. Since Venus orbits in retrograde if you were on Venus Earth would appear to be orbiting in retrograde.

Answer 5

Several more billion years from now, when the tidal forces placed on the planet from the Sun and the Moon, finally stop and then reverse the spinning of the planet. You can currently see the same on Mercury, where the day, is longer than it's year.