retrograde motion

Retrograde motion is the apparent backward movement of a planet against the background stars.

When Earth overtakes Mars in its orbit, Mars seems to reverse direction briefly before resuming its usual path—an optical illusion caused by relative orbital speeds.

In astronomy, retrograde also describes any orbit or rotation opposite to the normal direction of a system.

Astrologers attribute significance to retrograde periods, especially Mercury retrograde, blaming communication mishaps and travel delays on the planet's apparent reversal.