Comet C/2022 E3 (ZTF) is currently making its way through the northern skies and should reach its brightest magnitude in early February, according to In-The-Sky.org as it approaches perigee on Feb. 1. To see the comet for yourself, look to the north just after sunset and look for a faint greenish glow. Under the right dark sky conditions, the comet could be visible to the unaided eye, but binoculars will certainly make the job easier.
The comet last visited the Earth about 50,000 years ago and this may be its last visit before it leaves the solar system for good. The unusual green color results from a rare chemical reaction:
The comet itself isn’t green, but its head does appear to glow green thanks to a somewhat rare chemical reaction. The glow likely comes from diatomic carbon (C2) — a simple molecule made of two carbon atoms bonded together. When ultraviolet light from the sun breaks this molecule down, it emits a greenish glow that can last for several days, according to a 2021 study in the journal Proceedings of the National Academy of Sciences.
This eerie light disappears before making its way to the comet’s tail, or coma, which is made of gas. That gas is once again a result of solar radiation - in this case, sunlight causes part of the comet to sublimate, or transition from a solid into a gas without entering a liquid state. That gas streaks behind the comet, often glowing blue from the ultraviolet light.
The best, brightest views of the comet will be right around Feb 1, when it will be near the constellation Camelopardalis (almost due north, in the general vicinity of the Big and Little Dippers) right after sunset — use an app like Sky Guide to help find it. It’s cloudy here in Vermont until Friday…I’m going to try to catch a glimpse of it then.
Amazing photo of Comet C/2022 E3 (ZTF) above by Dan Bartlett.
Sometimes I forget what a big space dork I am and then a comet comes along and I’m texting everyone I know to get their asses outside to see the amazing sky thing. Anyway, what I’m trying to say is that this is a Comet Neowise fan blog now. After seeing it last night in my backyard,1 I went looking for some of the best photos of it.
After seeing it briefly two nights ago before some haze settled in (and only then with the aid of binoculars), I stepped out on my deck last night just after 10pm and bam, it was right there, totally visible with the naked eye. I grabbed the binoculars and got a pretty good view and then got out the telescope. Whoa, papa. Totally mind-blowing.↩
If you live in the US and Canada, you might have the opportunity to check out Comet NEOWISE over the next few weeks with a good pair of binoculars or even with the naked eye. EarthSky has the skinny.
By mid-July (around July 12-15), the comet will also become visible at dusk (just after sunset), low in the northwest horizon, for observers in the mid- and northern U.S. How can it be visible in both dawn and dusk? The answer is that the comet is now very far to the north on the sky’s dome. For those at latitudes like those in the southern U.S. (say, around 30 degrees north latitude), the comet is very nearly but not quite circumpolar, that is, it’s nearly in the sky continually, but it isn’t quite … that’s why we at southerly latitudes will have a harder time spotting it in the evening.
It appears this comet is holding up better than Comet ATLAS did earlier in the year. Here’s a beautiful time lapse of NEOWISE rising over the Adriatic Sea in the early dawn:
And a time lapse of the comet from the International Space Station (it starts rising around the 3-minute mark):
Last month, I told you about Comet ATLAS, which at that time looked capable of putting on a real show in the night sky.
Except, since its discovery, the comet has been brightening at an almost unprecedented speed. As of March 17, ATLAS was already magnitude +8.5, over 600 times brighter than forecast. As a result, great expectations are buzzing for this icy lump of cosmic detritus, with hopes it could become a stupendously bright object by the end of May.
It turns out the increase in brightness was fleeting — and possibly due to the comet breaking apart. In the past week, the Hubble Space Telescope has gotten two good looks at the disintegrating comet, identifying that the main mass has broken into about 30 fragments.
“This is really exciting — both because such events are super cool to watch and because they do not happen very often. Most comets that fragment are too dim to see. Events at such scale only happen once or twice a decade,” said the leader of a second Hubble observing team, Quanzhi Ye, of the University of Maryland, College Park.
The results are evidence that comet fragmentation is actually fairly common, say researchers. It might even be the dominant mechanism by which the solid, icy nuclei of comets die. Because this happens quickly and unpredictably, astronomers remain largely uncertain about the cause of fragmentation. Hubble’s crisp images may yield new clues to the breakup. Hubble distinguishes pieces as small as the size of a house. Before the breakup, the entire nucleus may have been no more than the length of two football fields.
When astronomers first spotted Comet ATLAS in December, it was in Ursa Major and was an exceedingly faint object, close to 20th magnitude. That’s about 398,000 times dimmer than stars that are on the threshold of naked-eye visibility. At the time, it was 273 million miles (439 million kilometers) from the sun.
But comets typically brighten as they approach the sun, and at its closest, on May 31, Comet ATLAS will be just 23.5 million miles (37.8 million km) from the sun. Such a prodigious change in solar distance would typically cause a comet to increase in luminosity by almost 11 magnitudes, enough to make ATLAS easily visible in a small telescope or a pair of good binoculars, although quite frankly nothing really to write home about.
Except, since its discovery, the comet has been brightening at an almost unprecedented speed. As of March 17, ATLAS was already magnitude +8.5, over 600 times brighter than forecast. As a result, great expectations are buzzing for this icy lump of cosmic detritus, with hopes it could become a stupendously bright object by the end of May.
If Atlas manages to remain intact, some in the field have suggested it could grow from magnitude +1 to possibly -5. At the brightest extreme, it could be visible even during the day.
The location of the comet is also notable-unlike more recent comets, it will be best viewed in the Northern Hemisphere.
Chuck Ayoub recently captured the comet arcing across the night sky with his backyard astrophotography rig:
Oh I hope Comet ATLAS can keep it together. I vividly remember going outside in rural Wisconsin darkness to see the tail of Comet Hyakutake stretch halfway across the sky. One of the most amazing things I’ve ever seen.
Update: It looks as though Comet ATLAS will not be dazzling naked-eye observers later this spring — the comet seems to have broken into 3 or 4 pieces as it nears the Sun.
Although I guess Comet ATLAS is good news if you’re looking for signs of the apocalypse too. Pandemic: check. Bright new light in the sky: check.↩
Director Christian Stangl and composer Wolfgang Stangl used millions of photos (that’s right, millions!) taken by the ESA’s Rosetta spacecraft of Comet 67P/Churyumov-Gerasimenko to make this short video that makes the mission feel like sci-fi a la Alien or District 9.
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