One of our patrons heard someone blame their bad luck on Mercury being retrograde. They’d heard the expression before, but had never stopped to think about what it meant.
We found our answer in The Total Skywatcher’s Manual by Linda Shore, David Prosper, and Vivian White, Wonders of the Solar System by Brian Cox, and The Cambridge Encyclopedia of Amateur Astronomy by Michael E. Bakich. Retrograde motion is when a planet appears to move backyard in the sky, going from east to west. (The opposite – the normal, west-to-east movement -- is called prograde motion.) When a planet is retrograde, it isn’t actually moving backwards. It has to do with that planet’s orbit around the sun relative to Earth’s. When Earth catches up to a planet and overtakes it, the other planet appears to move in the opposite direction, like when a fast car passes a slower one on the highway.
Susan Miller, writing for AstrologyZone.com, explains what astrologists think about Mercury retrograde. Mercury is said to rule communication as well as formal contracts and agreements, and when it is in retrograde, it is in a “resting” state, so problems might arise in those areas. This is why some people don’t like making big decisions or signing contracts during Mercury retrograde periods. However, it’s also said to be a very intuitive period, and a good time to reflect on the past.
According to the 2017 edition of The Old Farmer’s Almanac, Mercury will be retrograde from January 1-9, April 9-May 3, August 13-September 5, and December 3-23 in 2017.