Mercury has been in retrograde since December 3, and will be until December 22. And people all over the world are citing the planet's movements as the cause of their relationship tension and work snafus.

In reality, Mercury in retrograde isn't such an unusual occurrence: The planet goes into retrograde about four times a year. According to NASA's website, when a planet is in retrograde, it only appears to be moving backwards.

"It is not REAL in that the planet does not physically start moving backwards in its orbit," the site reads. "It just appears to do so because of the relative positions of the planet and Earth and how they are moving around the Sun."

Specifically, the Earth moves faster in its orbit than Mars does. So until Mercury – which is the planet closest to the Sun – inevitably catches up, it looks like Mercury is moving in reverse.

I asked Michelle Nichols, the director of public observing at the Adler Planetarium in Chicago, what effect Mercury being in retrograde has on our daily lives.

"None," she told me. "Zero. Other planets in the solar system have no effect on our planet. Everything is just too far away."

She added, "You could hold out a book in your hand and the gravitational effect of that book on you is going to be greater than Mercury's."

Nichols said our awareness is simply heightened when we know Mercury is in retrograde. There's no link between, say, fighting with your partner and the movement of the solar system.

Shelley Ackerman, a board member at the International Society for Astrological Research, thinks otherwise. She directed me to a book that cites Mercury as the "communication planet," influencing organising, perception, learning, and health as well.

But Ackerman said Mercury retrograde isn't an inherently negative event. It's a time to slow down and review different aspects of your life, Ackerman said – you'll only run into trouble if you're rushing and speeding ahead.

Ackerman noted that at least one-fifth of the population is born during Mercury retrograde. "The main thing is to not be fearful of it," she said, "but to recognise that we're supposed to slow down and pay extra attention."

A 2016 article in Mental Floss traces the evolution of the hype about Mercury retrograde. During the mid-18th century, British agricultural almanacs mentioned Mercury retrograde, to help farmers line up their planting schedules with the patterns of the stars.

As astrology became more popular in the 1970s, according to Mental Floss, Mercury retrograde began appearing in horoscopes and even some news reports.

Still, Nichols told me, "Based on scientific evidence, if you take all the times that Mercury goes into retrograde during the year and you map out when good or bad things happen, there's no correlation or causation.

"This is not anything astronomers are worried about."

This article was originally published by Business Insider.