A Super Worm Moon Is Coming on the First Day of Spring

iStock.com/Sjo
iStock.com/Sjo

So far, 2019 has been a treat for astronomy fans. The last supermoon (and the brightest one of the year) was visible on February 19, and the next one is set to appear barely a month later on Wednesday, March 20, the first day of spring. Instead of the snow moon that came last month, this upcoming celestial event will be a super worm moon.

What is a supermoon?

A supermoon is defined as the Moon's seemingly larger size when viewed from Earth. The Moon is constantly circling our planet, and its apparent size in the night sky changes depending on where it is in its oval-shaped orbit. Its perigee is the point in its orbit that brings it closest to Earth; when the Moon reaches its perigee on a day when it's full, it's officially a supermoon.

Full moons also have different nicknames based on the time of year they occur. Last month's event was a snow moon: the first full moon that appears in February. March's supermoon will be a worm moon. A worm moon is usually the last full moon of winter, and it's named after the earthworms that start wriggling their way through the soil as spring approaches. In this case, the full moon coincides with the vernal equinox—the start of the spring season. The last time a full moon coincided with the first day of spring was March 20, 1981.

When to watch the next supermoon

The best time to catch the next supermoon are the nights of Tuesday, March 19 and Wednesday, March 20. At 2:48 p.m. on Tuesday, the Moon will reach its perigee, and at 8:43 p.m. ET on Wednesday, the Moon will be at its fullest. The Moon will also appear especially close and bright on the days surrounding the spring equinox.

Supermoons have felt like a common occurrence this year, with three appearing in the first three months in 2019. But after the worm moon, they will be much rarer: The next supermoon with a full moon won't happen until 2020. There will, however, be two new moon supermoons in August, but even though the Moon will be at the closest point in its orbit during the events, it won't be visible in the night sky.

What is Mercury in Retrograde, and Why Do We Blame Things On It?

NASA
NASA

Crashed computers, missed flights, tensions in your workplace—a person who subscribes to astrology would tell you to expect all this chaos and more when Mercury starts retrograding. For the remainder of 2019, that means October 31-November 20. But according to an astronomer, this common celestial phenomenon is no reason to stay cooped up at home for weeks at a time.

"We don't know of any physical mechanism that would cause things like power outages or personality changes in people," Dr. Mark Hammergren, an astronomer at Chicago's Adler Planetarium, tells Mental Floss. So if Mercury doesn’t throw business dealings and relationships out of whack when it appears to change direction in the sky, why are so many people convinced that it does?

The History of "Mercury in Retrograde"

Mercury retrograde—as it's technically called—was being written about in astrology circles as far back as the mid-18th century. The event was noted in British agricultural almanacs of the time, which farmers would read to sync their planting schedules to the patterns of the stars. During the spiritualism craze of the Victorian era, interest in astrology boomed, with many believing that the stars affected the Earth in a variety of (often inconvenient) ways. Late 19th-century publications like The Astrologer’s Magazine and The Science of the Stars connected Mercury retrograde with heavy rainfall. Characterizations of the happening as an "ill omen" also appeared in a handful of articles during that period, but its association with outright disaster wasn’t as prevalent then as it is today.

While other spiritualist hobbies like séances and crystal gazing gradually faded, astrology grew even more popular. By the 1970s, horoscopes were a newspaper mainstay and Mercury retrograde was a recurring player. Because the Roman god Mercury was said to govern travel, commerce, financial wealth, and communication, in astrological circles, Mercury the planet became linked to those matters as well.

"Don’t start anything when Mercury is retrograde," an April 1979 issue of The Baltimore Sun instructed its readers. "A large communications organization notes that magnetic storms, disrupting messages, are prolonged when Mercury appears to be going backwards. Mercury, of course, is the planet associated with communication." The power attributed to the event has become so overblown that today it's blamed for everything from digestive problems to broken washing machines.

What is Mercury in Retrograde?

Though hysteria around Mercury retrograde is stronger than ever, there's still zero evidence that it's something we should worry about. Even the flimsiest explanations, like the idea that the gravitational pull from Mercury influences the water in our bodies in the same way that the moon controls the tides, are easily deflated by science. "A car 20 feet away from you will exert a stronger pull of gravity than the planet Mercury does," Dr. Hammergren says.

To understand how little Mercury retrograde impacts life on Earth, it helps to learn the physical process behind the phenomenon. When the planet nearest to the sun is retrograde, it appears to move "backwards" (east to west rather than west to east) across the sky. This apparent reversal in Mercury's orbit is actually just an illusion to the people viewing it from Earth. Picture Mercury and Earth circling the sun like cars on a racetrack. A year on Mercury is shorter than a year on Earth (88 Earth days compared to 365), which means Mercury experiences four years in the time it takes us to finish one solar loop.

When the planets are next to one another on the same side of the sun, Mercury looks like it's moving east to those of us on Earth. But when Mercury overtakes Earth and continues its orbit, its straight trajectory seems to change course. According to Dr. Hammergren, it's just a trick of perspective. "Same thing if you were passing a car on a highway, maybe going a little bit faster than they are," he says. "They're not really going backwards, they just appear to be going backwards relative to your motion."

Embedded from GIFY

Earth's orbit isn't identical to that of any other planet in the solar system, which means that all the planets appear to move backwards at varying points in time. Planets farther from the sun than Earth have even more noticeable retrograde patterns because they're visible at night. But thanks to astrology, it's Mercury's retrograde motion that incites dread every few months.

Dr. Hammergren blames the superstition attached to Mercury, and astrology as a whole, on confirmation bias: "[Believers] will say, 'Aha! See, there's a shake-up in my workplace because Mercury's retrograde.'" He urges people to review the past year and see if the periods of their lives when Mercury was retrograde were especially catastrophic. They'll likely find that misinterpreted messages and technical problems are fairly common throughout the year. But as Dr. Hammergren says, when things go wrong and Mercury isn't retrograde, "we don't get that hashtag. It's called Monday."

This piece originally ran in 2018.

How to Catch the Transits of Mercury and the 'Demon Star' This Month

Allexxandar/iStock via Getty Images
Allexxandar/iStock via Getty Images

This month's sky-gazing event calendar is all about transits. In astronomy, a transit occurs when one celestial body appears to pass directly in front of another in the night sky, causing the light from one body to diminish in some cases. As Geek reports, there are two main transits to look out for in November: that of Mercury moving across the sun and the dimming and brightening of the "demon star" Algol.

What is a Mercury transit?

Mercury is currently in retrograde (though you shouldn't blame that for any chaos in your personal life). As the innermost planet travels "backwards" across the sky this month, it will make a rare detour past the face of the sun on November 11. Mercury's transit across the sun is something that only happens roughly 13 times every 100 years. Such an event won't be seen again in the U.S. until 2049.

This time around, it will take Mercury about five and a half hours—starting just after sunrise on the East Coast—to make the full journey from one end of the bright yellow disc to the other.

What is a "demon star" transit?

The transit of Algol, also known as the demon star, is a much more common event, but it's no less spectacular. Algol is really two stars in the constellation Perseus that are constantly orbiting each other. Every 2.86736 days, the smaller star of the pair passes in front of the larger star, making it appear slightly dimmer for 10 hours at a time. In the first half of the month, most of these transits occur after sunset on the East Coast, which is the best time to observe the transition. The next is set for November 9 at 3:17 a.m. EST, with the one after that taking place on November 12, six minutes after midnight.

Algol gets its monstrous nickname from a classic villain of Greek mythology. The star is supposed to resemble the winking, snake-haired head of the gorgon Medusa, who was slain by Perseus. Algol is a name derived from an Arabic word meaning "the demon's head."

How to see Mercury's and Algol's transits

To see both of these events, you'll need some special equipment. Looking directly at the sun is never a good idea, and NASA recommends using a telescope with a certified sun filter to watch Mercury's transit safely on November 11. A solar projection box or sun funnel would also allow you to observe the planet's passage without damaging your eyes.

There's no harm in looking straight at the twin stars that make up Algol, but you'll have trouble seeing them "blink" with your naked eye. For that event, a regular telescope or binoculars would do.

[h/t Geek]

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