New Year, New Sky: A January Skywatching Guide

iStock
iStock

The New Year brings a great meteor shower, a rarely visible planet, a "blue moon," and a total lunar eclipse. Here are a few things skywatchers should be on the lookout for as they begin 2018.

JANUARY 1: VISIBLE MERCURY & WOLF SUPERMOON

Just before sunrise on New Year's Day, Mercury will be visible in the sky. Because of its proximity to the Sun, you can only see the planet on a handful of days every year—when Mercury reaches “greatest elongation”—and even then, you only have a narrow window of opportunity to see it. (For reference: In New York State, the magic hours are between roughly 5:30 a.m. and 6:00 a.m. Mercury will peak in the southeast a mere 10 degrees over the horizon. The times and maximum height over the horizon will vary based on your location. Check for your location here.) If you're pulling a New Year all-nighter anyway, be sure to make the effort.

Finding the southeast is easy. (Worst-case scenario, use the compass app in your phone.) But how do you calculate 10 degrees over the horizon? The easiest way is to hold your thumb out sideways at arm's length. The thickness of your thumb is about two degrees. A clenched fist, upright, is about 10 degrees. Hold the bottom of your fist at the horizon; the top of it will reveal an approximation of where Mercury should be.

That's not the only sky event on January 1. We'll also see the first full moon of 2018. It will be a “supermoon”—that is, it will be full while closest to Earth in its elliptical orbit. (Unless you are a devoted Moon watcher, you are unlikely to notice whether or not the Moon is a few percentage points larger than normal, so don't get too caught up in that.) According to the Old Farmer's Almanac, Native Americans called this first full moon in January the Wolf Moon, because winter has been in full swing for a while now, and wolves are hungry. There's a little extra longing in those customary howls.

JANUARY 3–4: QUADRANTIDS METEOR SHOWER

On January 3 at around 11:00 p.m., you can celebrate J.R.R. Tolkien's birthday (and mine) by finding an area of little light pollution, laying out a blanket, turning off your phone, opening a bottle of wine, and letting your eyes adjust to the darkness. Just before midnight, your eyes should be good and ready to enjoy the first major meteor shower of 2018: the Quadrantids. On a good year, you'll be able to catch around 70 meteors per hour. This, however, will not be a good year, because of an almost fully illuminated moon which will wash out the night sky. All is not lost, however: If the sky is clear and you've found a nice remote area, you're sure to see something through the predawn hours of January 4.

The Quadrantids are particularly interesting for two reasons: 1. They are named for Quadrans Muralis, a constellation “drawn” by an 18th-century French astronomer, but which fell out of favor in the late 1800s and does not formally exist today, according to the International Astronomical Union; and 2. The meteor shower is produced by 2003 EH1, a near-Earth asteroid that is believed to be an extinct comet. (With no volatiles left to sublimate and give it that distinct comet tail, or coma, the comet essentially becomes a hunk of space rock. We still love it, but it's no Halley.)

JANUARY 31: BLUE SUPERMOON ECLIPSE

Every month begins or ends with a full moon, more or less. The lunar phases are where we get the word "month" in the first place. Every so often, the lunar cycle so aligns as to give us two full moons in one month. This second full moon is called a "blue moon" (as in: "once in a … "). There's no cosmic magic about it, though it is a lovely way to acknowledge the beauty of celestial mechanics. The blue moon on January 31 will be a particularly good showing, as it is a supermoon, and in the western United States, across the Pacific, and into eastern Asia, there will be a total lunar eclipse! At moonset, the Moon will cross through the darkest part of the Earth's shadow and turn a reddish color. No telescopes or special protective glasses will be needed to enjoy this. (The eastern United States will experience a partial lunar eclipse, whereupon a part of the moon will darken. It's better than nothing!)

If your January skywatching is ruined with rain and alarm clocks that didn't go off, don't lose hope. Next month promises a minor meteor shower, a "black moon," and the always-romantic Valentine's Day star.

Editor's Note: This post has been updated.

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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