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Look Up Again! The Final Supermoon of 2016 Rises Tonight

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Last month's supermoon: on November 14, you could see it rising above Athens through the propylaea of the Acropolis. Image Credit: AFP/Aris Messinis/Getty Images

 
You might be sick to death of hearing about "supermoons." If that's the case, I bring good news: tonight, December 13, you'll see the final supermoon of 2016. If you're not sick of them, I also bring good news, because you have one more supermoon to see.

Of course, where there is good news there is bad, and it's this: The supermoon will make it very difficult to catch the Geminid meteor shower, which peaks tonight. Don't give up, however; because of the sheer volume of meteors that comprise the Geminids, you might see some shooting across the sky.

WHAT IS A SUPERMOON?

Before last year, when the red harvest supermoon took over the world, you might never have heard of a supermoon. And now we've had three in a row to close out the year: October's super hunter's moon, November's super beaver moon, and now December's full cold or long nights supermoon. This is true in part because supermoon is not an astronomy term, but rather, one of astrology. (In case you are wondering about the difference: astronomy is science; astrology is make believe.) The name has stuck of late because it's Twitter-friendly and a lot easier to remember than the actual name for the phenomenon: perigee-syzygy of the Earth–Moon–Sun system.

If you want to understand what's going on and why there are so many supermoons recently, you really do need to look at the proper name. Perigee occurs when the Moon is closest to the Earth in an orbit. Remember: the Moon's orbit is not a perfect circle; rather, it's elliptical. Sometimes it's close to Earth. Sometimes it's farther away.

Syzygy means three celestial objects are in alignment. (It can be the Sun, Earth, and Moon, but it might be the Sun, Venus, and Earth, for example, when astronomers can view Venus cross the solar disc.) So when do the Earth, Sun, and Moon experience syzygy? In one of two instances: either the Moon is between the Sun and the Earth (that's a new moon, because from our vantage, the Moon is completely black; the far side of the Moon is in full illumination) or the Earth is between the Sun and the Moon (a full moon, when the Sun's rays are lighting the side we see).

Bear in mind that this does not mean perfect alignment. The phases of the moon have nothing to do with the Earth's shadow.

So a perigee-syzygy of the Earth–Moon–Sun system means an alignment that occurs when the Moon is near to the Earth. It could be a full moon. It could be a new moon. Easy, right? Inasmuch as a made-up term from a made-up belief system can have a proper definition, a supermoon generally means a full moon.

WHY ARE THERE SO MANY SUPERMOONS THIS YEAR?

Not every full moon is at perigee (or its opposite, apogee, when the Moon is farthest from the Earth). The lunar cycle—the number of days it takes the Moon to experience each of its phases, new moon to new moon—lasts about 29 and a half days. Every 14 lunar cycles, the full moon coincides with perigee.

Supermoons tend to come in threes, however. The reason is that the full moons preceding and succeeding perigee-syzygy are still inordinately close to the Earth, and thus appear a lot larger than normal. Moons that are 224,641 miles or closer to the Earth are considered supermoons. The result: a supermoon trifecta, three in a row.

So if you've experienced supermoon overload this year, take comfort that it'll be more than a year before you have to hear the term again. Enjoy it: 2016 has been a year of wildly unexpected and sometimes awful events. Something as predictable and wonderful as the cosmos can be a great comfort indeed.

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Eclipses Belong to Families That Span Millennia
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If you’re lucky enough to see the solar eclipse when it passes over America on August 21, you’ll bear witness to a centuries-long legacy. That’s because total eclipses of the sun aren’t isolated incidents that occur at random. They belong to interconnected eclipse families that humans have been using to track the phenomena since long before the first telescope was invented.

In the latest installment of StarTalk on Mashable, Neil deGrasse Tyson chats with meteorologist Joe Rao about the science behind eclipse families. According to Rao, eclipses follow Saros cycles which repeat every 18 years, 11 days, 8 hours. Astronomers keep track of many different Saros cycles. The eclipse on August 21, for example, is a member of the family Solar Saros 145. Every 18 years a Saros 145 eclipse falls over a different third of the Earth. In 1999, the great American eclipse’s “cousin” appeared in the skies over Europe and south Asia, and 18 years before that another relative could be seen over modern Russia. The Solar Saros clan can be traced all the way back to 1639 and it will keep going until 3009.

Today, scientists have space-age technology that allows them to track the moment of totality down to a fraction of a second. But thousands of years ago, before such satellite-tracking equipment was invented, ancient Babylonians only knew what they could observe from Earth. Their eclipse calculations ended up serving them pretty well: They were able to predict the same 18-year cycle we know to be true today.

Saros 145 isn’t the only family of eclipses making its way around the Earth. There are enough solar eclipse cycles to make the event a fairly common occurrence. If you’re curious to see how many will happen in your lifetime, here’s where you can calculate the number.

[h/t Mashable]

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7 Maps of Fun Eclipse Viewing Locations
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Do you have your protective glasses and camera filter ready for the great American solar eclipse on August 21? Perfect. Now all you need to do is pick the ideal location for scoping out the event. Fortunately, the path of totality (the area from which the moon’s total coverage of the sun is visible) stretches from Oregon to South Carolina, and there are plenty of places in between where you can set up camp. We’ve tracked down maps of some of the most unique locations that will fall beneath the moon’s shadow on Monday.

1. WATCH FROM A NATIONAL PARK.

What better place to witness one of the most stunning events in nature than from a national park? Using data from NASA’s Scientific Visualization Studio, the National Park Service has published a map of sites that will provide the best views of the celestial show. Several locations, from Great Smoky Mountains National Park in the East to John Day Fossil Beds National Monument in the West, fall in the path of totality. Click any marker in the interactive map to see if that place is hosting viewing events or other eclipse-related activities on August 21.

2. WATCH FROM THE CLOUDS.

When viewed from Earth, a total eclipse lasts only a few minutes. One way to get the most out of the experience is to head into the sky. You don’t need to board an invitation-only flight to see the eclipse from a bird's-eye perspective. There are plenty of airports in the path of totality, and NASA has compiled them all into a helpful map. In addition to choosing your departure and arrival points carefully, you’ll need to get the timing right. According to The Points Guy, taking an eastbound flight from a Pacific Northwest airport around 9 a.m., or a Denver, Colorado area airport around 10 a.m. will put you in a golden position for eclipse chasing—that’s assuming you can book a last-minute flight.

3. WATCH FROM A WAFFLE HOUSE.

On August 21, many Waffle House patrons will be treated to a mind-blowing experience—and we’re not talking about the topped and smothered hashbrowns. During the eclipse’s final hours it will be visible from dozens of Waffle Houses in the southern U.S. To choose a restaurant for viewing, refer to this map of Waffle Houses in the path of totality, put together by University of Georgia assistant geography professor Jerry Shannon. (He also tried making an eclipse map of Tim Hortons locations, but sadly fans of the Canadian chain won’t be so lucky.)

4. WATCH WHILE EATING FRIED CHICKEN.

Want some chicken to go with your waffles? Eclipse gazers watching from the southern states should have no trouble doing that. Twitter user Taber Andrew Bain made this map of fast food chicken joints that intersect with the path of totality. Bojangles' represents a healthy portion of the spots with 86 locations in the strip, but Zaxby’s is the most abundant by far with 117.

5. WATCH WITH WILDLIFE.

One of the more bizarre side effects of a solar eclipse is the reaction animals have to the sudden darkness. As most creatures time their habits to the rising and setting of the sun, totality can prompt different species to wake up, prepare for sleep, or just go berserk. We recommend watching this bizarre behavior with something separating you from the animals. NASA published a handy map of zoos that fall in the eclipse zone where you can do just that.

6. WATCH WITH SASQUATCH.

It’s not everyday a solar eclipse occurs in your backyard, and it’s definitely not everyday that you get to watch it in the company of Bigfoot. This map from cartographer and data visualization guru Joshua Stevens plots reported Sasquatch sightings in relation to the trajectory of the solar eclipse. It’s too bad that a bona fide Bigfoot encounter is a lot less likely to happen than a total solar eclipse—and even if you do spot the hairy guy on the big day, it might be hard to convince others of The X-Files-worthy coincidence.

7. WATCH FROM A LIBRARY.

Map of libraries hosting eclipse viewing events.
STAR_Net's NASA@ My Library initiative, Space Science Institute, the Gordon and Betty Moore Foundation, NASA, and Google.

Your local library isn’t just a great place to pick up free protective glasses leading up to the eclipse. It can also be a fun spot to witness the event itself. Libraries around the country are hosting viewing events on the day of, where visitors will be provided with the proper equipment and information about what they’re seeing. Check out NASA’s map of libraries organizing such programs to find one close to you.

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