Mercury Retrograde is a Visual Deception

Little is known about Mercury, a world that is still shrouded in mystery.

But one thing is certain: Mercury, the planet closest to the Sun, doesn’t actually move backwards and retrograde, and it doesn’t affect us here on Earth. The concept of Mercury retrograde, where communication and travel are temporarily disrupted, is often mentioned in astrology, but of course, this is just fun speculation. The phenomenon occurs when Mercury appears to start moving backwards across the sky.

But this is a trick of perception. Mercury retrograde Apparent movementFor example, when you pass a car going at high speed on the highway and the car appears to be moving backwards. This is not an exceptional or significant occurrence.

“There’s nothing unusual about this,” Tans Deyran, a physicist at Washington University in St. Louis who leads NASA’s telescope observations, told Mashable.

Because it happens so often — three or four times a year — some people easily associate misunderstandings, travel issues and other incidents with the event. “People are actively looking to connect,” Daylan says.

Causes of Mercury Retrograde

From our perspective, the planets, including Mercury, move across the night sky from west to east relative to the stars – in fact, Greek and Roman astronomers called the planets “wandering stars.”

If you were to look down at the Sun from above, you would see the planets orbiting counterclockwise, which produces an eastward motion from Earth’s perspective. but DeLan emphasized that this phenomenon changes when the two planets align in their orbits around the Sun, causing the inner planet (Mercury) to move faster than the outer planet (such as Earth), resulting in “apparent retrograde motion.” Obvious That’s because Mercury, which orbits the Sun at over 100,000 miles per hour, doesn’t suddenly start moving in the opposite direction.

The NASA diagram below uses Mars and Earth to explain apparent retrograde motion: When planets align, or when one planet “overtakes” another, the planets’ appearance in the sky changes, but their actual orbits do not.

A depiction of apparent retrograde motion.
Credit: NASA

The southern hemisphere of Mercury as seen by NASA’s MESSENGER spacecraft.
Credits: NASA / Johns Hopkins University Applied Physics Laboratory / Carnegie Institution of Washington

Mercury retrograde will last for several weeks, so don’t be surprised to hear that it has to do with a variety of events. Interestingly, Mercury retrograde recently resumed on August 5, 2024, after the chaos of the global CrowdStrike.

Although we know that nothing unusual is happening around Mercury’s orbit throughout the year in the solar system, Mercury will remain a world of mystery. It is a difficult planet to observe from Earth due to its closeness to the Sun. “That means that Mercury is only visible for a short time just before sunrise and just after sunset, and always appears close to the horizon,” explains the European Space Agency. Furthermore, it is very difficult to reach Mercury, and spacecraft that go there have to fight the overwhelming gravity of the Sun. That’s why Mercury is the least visited of the inner planets. Also, the planet’s surface, hot enough to melt lead, radiates heat into space, making it dangerous to get too close to Mercury. The ongoing BepiColombo mission is a joint European-Japanese project designed to withstand these extremes while performing an unprecedented flyby.

Planetary scientists hope to soon have many questions about Mercury answered. Does it have water? Is it geologically active? How did it get so close to the Sun?

But at least its strange apparent behaviour is better understood.

“Nothing special,” Daylan said.