Here’s How to See the Brightest Comet of 2018 This Weekend
It's really nice that all Mariah Carey wants for Christmas is "you," but for the rest of us, the consumer aspect of the holiday is a pretty big deal. This year, whether you have a "you,” or a mom who’s willing to wait on the Supreme line for that variety jacket you want, the universe is offering you a little something special for the holidays (that cannot be found on Amazon): a green-glowing "Christmas comet," that will shine brighter when it passes Earth on Sunday, December 16, than it will for the next 20 years.
According to Astronomy database, Sky & Telescope, the shooting space rock spans 1.2-kilometers (about three quarters of a mile) in width, and it'll pass by Earth from a mere 7.5 million miles away. Seven and a half million may sound like a lot, but it's actually about 30 times the distance between the Earth and the moon, and if you recall, you can see the moon. Like, pretty clearly. This is about as close as comets will ever get to our stratosphere, so naturally, the views will be great.
For us plebes without specialty telescopes, most comets aren't actually visible at all -- but because this Grinch-comet is passing so close to Earth, it's a special case. It'll be completely visible to the naked eye. According to NASA's Astronomy Picture of the Day, Comet 46P/Wirtanen has already been declared the sky's brightest comet at this point in time, so it's clearly one to get outside and see for yourself.
What is the Christmas Comet?
This odd Green Goblin-esque space rock is something called a short-period comet, which means that it orbits the sun every five and a half years. It's referred to by astronomers as 46P/Wirtanen, and it was first discovered in 1948 by Carl Wirtanen at the Lick Observatory just outside of San Jose, California.
Our little 46P friend is not predicted to make an appearance this bright, or this close, for the next 20 years.
When will the Christmas Comet peak?
You're hands-down optimal viewing window will fall on December 16, when the comet is at its closest and brightest. There's no designated time -- though, of course, it won't be easy to spot during daylight hours. Come nightfall, however, the thing should be glowing green and proud, no matter your viewing location.
If you're dead-set on viewing the thing on Christmas for personal, holiday-related reasons, your best bet is to try December 23 -- that's the closest you'll get. By then, 46P/Wirtanen will be far higher in the sky, recognizable for its proximity to a crazy bright star called Capella. If you happen to have a telescope lying around, you might wanna give that a shot.
How do I actually see the comet?
Looking for anything in the night sky is a pretty daunting task. There's a lot of stuff up there. When it comes to tracking down the glorious 46P/Wirtanen, astronomers suggest using an app like Sky Guide to help you locate its exact positioning, relative to the moon (which is particularly bright in December).
If you're not committed enough to bother with the whole app ordeal, you can actually locate the thing in relation to the constellation Orion's Belt. If you find the three famed stars that make up the classic constellation in the southeastern sky, you can follow the ark from lowest to highest star with your eyes, then look ever-so-slightly upward, where you'll see a remarkably bright, faintly red star, just free floating up there, with no constellation to belong to (this is called Aldebaran in Taurus). Look a little higher, and you'll see a star cluster best known as the Seven Sisters (formally referred to as the Pleiades star cluster), and your 46P/Wirtanen should fall just a little lower, and to the left.