Explaining Mercury's "Backward" Movement

The following continues our exploration of the phenomenon known as Mercury Retrograde, currently taking place between September 10 and October 1.

Mercury Retrograde itself is not a physical or actual “backwards” movement of the planet in its orbit--rather, it's an optical illusion created by the effect of two objects moving through space in the same direction but at different speeds. The effect can be illustrated by the example of two cars traveling down the highway--when one speeds up or slows down, it appears that the slower moving car is moving “backwards” relative to the motion of the faster moving car. This is the same concept to which our perception of Mercury Retrograde applies.