The stars are in motion, of course, but they are so far away that their apparent motion is negligible. The planets, however, are much closer and their motion is more apparent.

But, at least, its strange apparent motion is well understood. "There's nothing fancy about it," Daylan said. This story has been updated with more information about Mercury retrograde.

Earth will overtake Mars on Nov. 7. Finally, on December 10, the combined movements of Earth and Mars will cancel out the apparent backward motion, with Mars reaching a second stationary point.

Mars entered this retrograde motion on Sunday, October 30 and it will continue to do so until January 12. The apparent motion of Earth and Mars in the sky respectively. Image Credit: NASA/JPL-Caltech ...