Earth's orbit

[jus some gal]

Will the Earth ever experience retrograde motion?
Or does anyone know a site that might help me? Thanks!
XxX

[jake-the-peg]

retrograde is normally used to refer to an apparent orbit. That is the way a planet appears to move through the sky.

This happens when the Earth "Overtakes" a planet like Mars.

As we overtake Mars it appears to go backwards like this:
http://agham.asti.dost.gov.ph/1998/2nd/extras/ images/sRetro.jpg

It was strong evidence that the Earth goes around the sun and not the other way around. To make the system work the other way around Ptolemy had to introduce crystal sphere's going around other crystal spheres and all sorts of nonsense.

So obviously the Earth cannot sudenly start going backwards

[Teddio]

The Earth orbits the Sun anticlockwise with respect to the Sun's north pole. There is no way it can suddenly reverse its direction. Viewed from a cloudy Venus or the crystal clear skies of Mercury, Earth will appear to move clockwise for a few weeks in its orbit around the Sun. This effect is only apparent and is referred to as retrograde motion.

[jus some gal]

Thank you both very much for taking the time to post such incitful answers! XxX

[Azalian]

If you stand on Mercury or Venus you will see retrograde motion of the Earth.