Retrograde Mars . ... Credit Copyright: Tunc Tezel Explanation: Why would Mars appear to move backwards? Most of the time, the apparent motion of Mars in Earth's sky is in one direction, slow but steady in front of the far distant stars. ... Also during this time, Mars appeared to move backwards in the sky, a phenomenon called retrograde motion . ... At the top of the loop, Earth passed Mars and the retrograde motion was the highest. ... NASA Web Site Statements, Warnings, and Disclaimers . ...