Most of the time when you hear the words “Mercury retrograde,” it’s someone talking about astrology. Mercury in retrograde is an astrological phrase that somehow explains all kinds of bad things happening, if you believe in astrology. But retrograde is a real phenomena for planets in orbit. It just doesn’t mean all that much when you understand it.
“Retrograde” conveys the idea that the planet, whether Mercury, Mars, or whichever, is moving backwards. Planets do not move backwards. But they can appear to, which is an illusion Joss Fong explains here visually. Mercury does it about four times a year! No wonder astrologers depend on it so much. -via Laughing Squid