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New Year, New Sky: A January Skywatching Guide

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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.

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Astronomers Discover 12 New Moons Around Jupiter
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As the largest planet with the largest moon in our solar system, Jupiter is a body of record-setting proportions. The fifth planet from the Sun also boasts the most moons—and scientists just raised the count to 79.

A team of astronomers led by Scott S. Sheppard of the Carnegie Institute for Science confirmed the existence of 12 additional moons of Jupiter, 11 of which are “normal” outer moons, according to a statement from the institute. The outlier is being called an “oddball” for its bizarre orbit and diminutive size, which is about six-tenths of a mile in diameter.

The moons were first observed in the spring of 2017 while scientists looked for theoretical planet beyond Pluto, but several additional observations were needed to confirm that the celestial bodies were in fact orbiting around Jupiter. That process took a year.

“Jupiter just happened to be in the sky near the search fields where we were looking for extremely distant solar system objects, so we were serendipitously able to look for new moons around Jupiter while at the same time looking for planets at the fringes of our solar system,” Sheppard said in a statement.

Nine of the "normal" moons take about two years to orbit Jupiter in retrograde, or counter to the direction in which Jupiter spins. Scientists believe these moons are what’s left of three larger parent bodies that splintered in collisions with asteroids, comets, or other objects. The two other "normal" moons orbit in the prograde (same direction as Jupiter) and take less than a year to travel around the planet. They’re also thought to be chunks of a once-larger moon.

The oddball, on the other hand, is “more distant and more inclined” than the prograde moons. Although it orbits in prograde, it crosses the orbits of the retrograde moons, which could lead to some head-on collisions. The mass is believed to be Jupiter’s smallest moon, and scientists have suggested naming it Valetudo after the Roman goddess of health and hygiene, who happens to be the great-granddaughter of the god Jupiter.

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ESA/Herschel/SPIRE; M. W. L. Smith et al 2017
Look Closely—Every Point of Light in This Image Is a Galaxy
ESA/Herschel/SPIRE; M. W. L. Smith et al 2017
ESA/Herschel/SPIRE; M. W. L. Smith et al 2017

Even if you stare closely at this seemingly grainy image, you might not be able to tell there’s anything to it besides visual noise. But it's not static—it's a sliver of the distant universe, and every little pinprick of light is a galaxy.

As Gizmodo reports, the image was produced by the European Space Agency’s Herschel Space Observatory, a space-based infrared telescope that was launched into orbit in 2009 and was decommissioned in 2013. Created by Herschel’s Spectral and Photometric Imaging Receiver (SPIRE) and Photodetector Array Camera and Spectrometer (PACS), it looks out from our galaxy toward the North Galactic Pole, a point that lies perpendicular to the Milky Way's spiral near the constellation Coma Berenices.

A close-up of a view of distant galaxies taken by the Herschel Space Observatory
ESA/Herschel/SPIRE; M. W. L. Smith et al 2017

Each point of light comes from the heat of dust grains between different stars in a galaxy. These areas of dust gave off this radiation billions of years before reaching Herschel. Around 1000 of those pins of light belong to galaxies in the Coma Cluster (named for Coma Berenices), one of the densest clusters of galaxies in the known universe.

The longer you look at it, the smaller you’ll feel.

[h/t Gizmodo]

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