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A Bright Green 'Christmas Comet' Will Fly the Closest To Earth In Centuries

Posted by BeauHD on from the perfect-timing dept.

On Sunday night, a comet that orbits between Jupiter and the sun will make its closest approach to Earth in centuries. According to Tony Farnham, a research scientist in the astronomy department at the University of Maryland, the comet will appear as a bright, fuzzy ball with a greenish-gray tint. "You've got a one-kilometer solid nuclear in the middle, and gas is going out hundreds of thousands of miles," says Tony. The comet glows green because the gases emit light in green wavelengths. The New York Times reports: The ball of gas and dust, sometimes referred to as the "Christmas comet," was named 46P/Wirtanen, after the astronomer Carl Wirtanen, who discovered it in 1948. It orbits the sun once every 5.4 years, passing by Earth approximately every 11 years, but its distance varies and it is rarely this close. As the comet passes by, it will be 30 times farther from Earth than the moon, NASA said. The proximity of 46P/Wirtanen provides an opportunity to research the tail of the comet and see farther into the nucleus.

The comet is visible now but it will shine even brighter on Sunday as it reaches its closest approach, 7.1 million miles from Earth. That may sound really far, but it is among the 10 closest approaches by a comet in 70 years, NASA said. Only a few of those could be seen with the naked eye. Don't worry if you miss the comet on Sunday. It should be just as visible for a week or two because its appearance will change gradually. After it moves on, it won't be this close to Earth again for hundreds, if not thousands, of years. Online charts can help pinpoint its location.

43 of 111 comments (clear)

  1. So went outside and I looked up tonight... by 93+Escort+Wagon · · Score: 4, Funny

    But all I got was a face full of rain. I live in the Pacific Northwest, you insensitive clod!

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    1. Re:So went outside and I looked up tonight... by Mashiki · · Score: 1

      You sure you don't live in Canada? 'Cause that's pretty normal around here for pretty much any type of spectacle like this. Northern Lights as far down south as the central US? Overcast Canada. Comet's and shooting stars? Overcast. Stargazing on a hot summer night? Sorry it's muggy, and the approaching front will cause it to piss down rain. Oh, and snow. The only time I remember it not being like that, is when they said Haley's Comet was going to be this great gigantic spectacle and would glow like the heavens(still got the Time magazine article on that one). Barely a blip in the sky.

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      Om, nomnomnom...
    2. Re:So went outside and I looked up tonight... by thegarbz · · Score: 1

      Puulleeese Pacific Northwest. You amateurs, where I live I'm lucky to see the full moon through the light pollution.

      Though seriously I'm thinking of pulling out the telescope (which I haven't used since I moved here), stacking every light pollution filter I have into the eyepiece and giving it a go. Though I suspect after an hour or so of setup to also get rained on.

    3. Re:So went outside and I looked up tonight... by 93+Escort+Wagon · · Score: 1

      You sure you don't live in Canada? 'Cause that's pretty normal around here for pretty much any type of spectacle like this.

      Well I'm fairly certain Canada only has about 100 people, all of whom live either in Vancouver or Toronto - and Vancouver is also in the Pacific Northwest.

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    4. Re:So went outside and I looked up tonight... by Mashiki · · Score: 1

      Well I'm fairly certain Canada only has about 100 people, all of whom live either in Vancouver or Toronto - and Vancouver is also in the Pacific Northwest.

      It's really closer to 1000, I should know. I run the largest dairy up here, gotta tell you though it's a real bitch shipping milk in plastic bags from Ontario to British Columbia, then putting them into plastic and paper cartons.

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      Om, nomnomnom...
  2. Deer in the deadlights by MrKaos · · Score: 1

    It's kind of like looking up at the avalanche and wondering if it is going to hit you.

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    My ism, it's full of beliefs.
  3. If only this could have been posted pre Monday by Crashmarik · · Score: 4, Informative

    Maybe on say Friday ?

    Oh well people will still get to see the comet.

    1. Re:If only this could have been posted pre Monday by Desler · · Score: 2

      You should just be glad this wasn't posted Tuesday in true Slashdot fashion.

    2. Re:If only this could have been posted pre Monday by syn3rg · · Score: 1

      A dupe probably will be...

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  4. Green light is green. by Anonymous Coward · · Score: 1

    "The comet glows green because the gases emit light in green wavelengths."

    Green light is green because it emits green light in green wavelengths.

    1. Re:Green light is green. by scdeimos · · Score: 2

      I always thought red light was red because it was angry.

  5. Seems pretty faint by SuperKendall · · Score: 1

    Looking up from the suburbs on a clear night tonight, I could not see it at all - the Sky Guide app was helpful in figuring out where it should be. Might try to go outside later and acclimate more to the dark for a while to try again.

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    "There is more worth loving than we have strength to love." - Brian Jay Stanley
  6. Lazy man's lookup link? by PolygamousRanchKid+ · · Score: 3, Funny

    Does anyone have a where and when to look for your location calculator link?

    I mean like, you type in "I am in Berlin" and the calculator says: "Set your alarm clock for 04:00, look South by Southwest, curse the weather, go back to bed".

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    1. Re:Lazy man's lookup link? by Anonymous Coward · · Score: 1

      From a quick search and a play with stellarium, it seems like the comet will be roughly in the area of the pleiades, so you want to look east, heading to south through the evening and into the morning.

    2. Re:Lazy man's lookup link? by Anonymous Coward · · Score: 1

      Find Orion and follow the 'belt stars" to the right if you are in the Northern hemisphere (to the left for Southern hemisphere). You may notice a bright star (part of a 'V' which is part of Taurus) - almost there. A little further is a small cluster of stars, all together - that is the Pleiades. This comet is supposed to be about 1/2 way between the 'V' and the cluster. Hope this helps.
      For those who need more help, look up Orion online and see the star pattern you are looking for in the sky. BTW, you can always find North (or South) using Orion. I also suggest installing "Stellarium" and exploring the night sky with that.

  7. That's a terrible chart by Solandri · · Score: 5, Informative

    Doesn't name the constellations. In fact it's difficult to even see the constellations on it. Try this chart from Sky and Telescope. The comet is currently between Taurus and the Pleiades. Most occasional stargazers can locate those.

    Don't expect much though. It's currently at its peak magnitude of 3.9. Magnitude 6.0 is the dimmest you can see in dark skies, with most visible stars falling between -1.5 and +5. You're not going to see it with the naked eye from a city. Maybe a fuzzy blob with decent binoculars. The closest bright star is Aldebaran, which at magnitude 1 is about 15x brighter.

    1. Re:That's a terrible chart by SuperKendall · · Score: 2

      Thanks fr the binocular thought, I think I was just able to see it from within a city on a clear night, by staying outside a bit and acclimating... very fuzzy and indistinct though.

      Even that star chart would have made it hard to find though, the Sky Guide app let me search for the comet specifically and lead me to where it was in the sky, also showing it next to a small but very distinctive grouping of stars (as you said the Pleiades) that made it pretty easy to see where it should be...

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      "There is more worth loving than we have strength to love." - Brian Jay Stanley
    2. Re:That's a terrible chart by bill_mcgonigle · · Score: 1

      This is the summary we were looking for.

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    3. Re:That's a terrible chart by thegarbz · · Score: 1

      Doesn't name the constellations. In fact it's difficult to even see the constellations on it.

      According to that chart it was right next to the Pleiades. If you can't find it based on that a constellation chart won't help you since you probably never looked into the night sky.

      But yes you're on point. Without a telescope, good binoculars or a camera to boost the contrast a bit along with a dark sky you're not going to see anything.

  8. Weird Aliens by wolfheart111 · · Score: 1

    For halloween we get a comet the shape of a scull, now a bright glowing green xmas tree comet.... were being had. :)

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    [($)]
  9. Bah Humbug by Anonymous Coward · · Score: 3, Interesting

    I have a real telescope and I am a pretty good amateur astronomer. I live at an elevation of 4000 feet in the mountains with low light pollution.

    I went out and looked at this comet last night (Saturday.) It was hard to spot with the naked eye. The quarter moon added a significant amount of light to the sky. With a modest telescope it was, in fact, a small barely discernible patch of green. Meh.

    The popular press seems to write up astronomy things that make good copy but are very hard to see, particularly for people who live in cities.

    Having said that, the constellation Orion was directly overhead and is very spectacular this time of year. No telescope required. The Orion Nebula (a.k.a. M42) is clearly visible near the end of the sword hanging from Orion's belt. This is definitely an easier to see and much more interesting object. Check it out.

    I must say that the 2017 total solar eclipse was a hell of an event. I went to Wyoming to see it and it was worth the trip. I am definitely going to Mexico (or Texas) in 2024 for the next "local" total solar eclipse. Some friends of mine and I were out last summer looking at Mars, Saturn and Jupiter with very good results.

    Bottom line: Astronomy is interesting and challenging. Just don't expect Hubble sized results without a Hubble sized budget.

    1. Re:Bah Humbug by SuperKendall · · Score: 1

      I totally agree about the solar eclipse. If you've seen a 99% eclipse you have seen nothing compared to a total solar eclipse, I saw it from Nebraska... I'll be somewhere watching the 2024 eclipse as well, and was sorely tempted to see one coming sooner - but you'd have to to to South America to see it, a bit too far for me.

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      "There is more worth loving than we have strength to love." - Brian Jay Stanley
    2. Re:Bah Humbug by xSander · · Score: 1

      That may explain why I didn't see it when I went out to a pretty much dark spot last Friday (no street lights, no buildings, just a highway road and water bodies all around). I was looking for the Geminids, thought I saw some dust-like flashes. The sky was not completely clear, after all. I did get the Pleiades on my camera, no green blob near it though. Maybe because the 1/3 moon was too overwhelming. I will have to try and identify other stars or star groups on that photo now.

    3. Re:Bah Humbug by 4im · · Score: 1

      Sure can - if you invest in a tracker. With that 50mm lens even a simple mechanical, wind-up tracker will do, provided you do a proper north alignment. For the 300mm lens, you'll have to go for a better model, something like a SkyWatcher StarAdventurer. There's some things to watch over, mirror lockup, ISO settings etc., lots of post-processing, but it is perfectly doable. You'll have to invest quite some time though, it's not point and shoot.

    4. Re:Bah Humbug by thegarbz · · Score: 1

      The popular press seems to write up astronomy things that make good copy but are very hard to see, particularly for people who live in cities.

      You just described the art in one sentence :-(

    5. Re:Bah Humbug by Megane · · Score: 1

      Don't forget the annular eclipse a few months before. I live near where both paths intersect, so it's going to be my "practice run" for the big one.

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  10. Looked with binoculars, couldn't see anything by gaiageek · · Score: 1

    Clear skies in a medium-sized Midwestern city and I didn't see anything that looked different from a star.

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    www.gaiageek.com
  11. Nuclear? by scdeimos · · Score: 2

    RTFA, that's nucleus!

  12. Good luck seeing it by scdeimos · · Score: 3, Informative

    It's magnitude 8.8. Nobody's going to see it with their naked eye - the limit there is about M6.7. GoSkyWatch and a decent set of 50mm binoculars should do the trick.

  13. You know... by helpfulcorn · · Score: 1

    The comet in the film Maximum Overdrive also was green... I don't want to jump to any conclusions but I am absolutely certain all of our devices will kill us for Christmas.

  14. The Day of the Triffids - John Wyndham by NuclearCat · · Score: 2

    Good reason to read it again :)

  15. Information only relevant to tachyons, no? by CSMoran · · Score: 2

    Considering it's Monday.

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    Every end has half a stick.
  16. At risk of sounding like a nerd... by SqueakyMouse · · Score: 2

    Emitting light in green wavelengths is not a sufficient condition for an object to appear green. Yellow and white objects also emit light in green wavelengths for example but do not appear green since they also emit other wavelengths. Then there are cases like the sun viewed from earth's surface where its colour is not just dependent on the wavelengths of light it emits but how the light is scattered by the atmosphere. There are also cases like blue feathers, which have no blue pigment, but still appear blue if you look at them from the right angle. There are of course other subtleties like redshift/blueshift.

    So telling us the comet's gas emits light in green wavelengths is informative and so is telling us that the comet would appear green to us but one statement does not imply the other.

    P.S. I thought the most obvious comment to make would be about a second coming of jesus or something given it's about a comet at christmas but haven't seen that so far. Strange.

    1. Re:At risk of sounding like a nerd... by Wulf2k · · Score: 1

      If the colour were somehow relevant to understanding the comet, or even expanded upon, it could be interesting.

      As phrased, it basically comes off as "it's green because it's green". There are no quirks to its colour to justify discussing wavelengths.

  17. Re: My name is GayPK and I'm gay!! by c6gunner · · Score: 1

    I like the part where that one guy says to him "I'm sure you have a great deal of valuable knowledge".

    Hilarious!

  18. What are the guidelines to name comets? by DontBeAMoran · · Score: 1

    The ball of gas and dust, sometimes referred to as the "Christmas comet," was named 46P/Wirtanen, after the astronomer Carl Wirtanen, who discovered it in 1948.

    If it was discovered in 1948, why is it named "46P/Wirtanen"? Why not "48P/Wirtanen"? And what does "P" mean? It's certainly not part of "COMET".

    And why is it in the "number slash name" format anyway? Wouldn't it be better to call it "Wirtanen 48"?

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    1. Re:What are the guidelines to name comets? by thrich81 · · Score: 3, Informative

      Without looking up some details, here are a couple of answers. The "P" means it is a periodic comet - one of the relatively few which have had an orbit determined. Comets originate way out on the edge of the solar system and many of them discovered have never been seen before and when they return to way out there, never will be again. The periodic comets have had their orbit perturbed by a planet at some time in the past and are in much smaller orbits with periods measured in tens of years (maybe hundreds) instead of tens of thousands. This comet 46P/Wirtanen has a relatively short orbital period of 5.4 years. The "46" means it is the 46th comet to have been assigned by the astronomical community as periodic. Discovered in 1948 and it is only the 46th determined periodic comet -- shows there are not many of them. The first assigned periodic comet is Halley's comet, now designated, 1P/Halley.

    2. Re:What are the guidelines to name comets? by DontBeAMoran · · Score: 1

      +5 informative.

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  19. stellarium website coolness factor x10 by AndrewFlagg · · Score: 1

    i checked out the link of the stellarium website and product. very cool. any others like this?

  20. Moving FAST! by kbahey · · Score: 4, Interesting

    This comet is moving really fast!

    Last night was the first break in the clouds in about a month and a half. So I got out my astrophotography rig, which is based on the open source OnStep STM32 telescope controller.

    The moon was bright, and there was too much moisture in the atmosphere. So, not ideal conditions.

    As far as comets go, this one is underwhelming. It lacks a tail, and is below naked eye visibility. But what is remarkable, is that this comet was sure moving fast against the background stars.

    A 5 minute exposure shows a fuzzy streak that goes in a different direction than the streaks from stars due to a hasty and inaccurate polar alignment.

    Here is a screenshot of the 5 minute exposure, and another 60 seconds exposure.

    Clouds rolled over and I had to call it a night.

    Oh, and if you want an Open Source telescope controller, here are more videos on OnStep on the STM32.

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  21. Full resolution images of 46P Wirtanen by kbahey · · Score: 2

    Here are full resolution images from yesterday.

    5 minute exposure.

    1 minute exposure. Even at that short of an exposure, the comet is zipping along in the sky ...

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  22. Comment removed by account_deleted · · Score: 1

    Comment removed based on user account deletion

  23. Nuclear by dcw3 · · Score: 1

    @BeauHD Do you read this stuff before you post it? Let me help you...
    http://www.pas.rochester.edu/~...

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