Here we go again. Mercury is currently in retrograde and will be until May 14. For some people, that is reason enough to make excuses for what may be going wrong in their lives. Blaming it on distant planets is very annoying, however, because that energy could be better spent pushing for change in society and from the institutions that actually make our lives worse.
Philosophically, we can look at Shakespeare and the immortal Cassius line: "The fault, dear Brutus, is not in our stars, but in ourselves." Personally, we prefer the words of Mewtwo: “I see now that the circumstances of one's birth are irrelevant. It is what you do with the gift of life that determines who you are.” And yet here we are, with people still believing that the astronomical actions of a cosmic object over 86 million kilometers away uniquely affects how their Monday is going, and blaming Mercury for their mystical misfortune. Astrology is, after all, not real.
What is retrograde motion?
The retrograde motion appears to happen to all planets simply because they are orbiting the Sun and not the Earth. When you think everything revolves around you, the planets seem to be moving all in one direction for a while. Then they appear to stop, move backward for a bit, and then revert to their normal path. This "flip it and reverse it" is known as retrograde motion.
Considering the retrograde period as a real physical thing is equivalent to believing that the Earth is at the center of the Universe. And while that would put you on the intellectual par of the Catholic Church of a few hundred years ago, it is simply not true. The planets do not stop all of a sudden in the sky, they don’t move backward, and then stop again.
The planets are all orbiting the Sun at different speeds. The laws of gravity, published 336 years ago in Isaac Newton’s Philosophiæ Naturalis Principia Mathematica, can help us calculate those – although Mercury is close enough to the Sun to require Einstein’s general relativity.
The effect of mercury retrograde on a person
In simple terms, the closer a planet is to the Sun, the faster it is going. If you imagine the orbits as concentric racetracks, it means that Mercury goes around the Sun every 88 days while Earth does it in about 365 days. As the two planets move around, Mercury will be lapping Earth about three times a year more or less.
But the Principia also tells us how much effect the planets have on humans. So, let’s calculate that. If you weigh 60 kilograms (132 pounds), the force that you impart on Mercury and that Mercury imparts on you is about 1.7x10-7 Newtons or around one-fifth of the weight of an eyelash hair on your skin. It really can’t be doing all the damage that people blame it for!
As always, heed the words of one Ms. Britney Spears and choose your own destiny