Many of you are probably aware of the arrival of Comet McNaught. Here’s a shot of the comet at sunset in Seattle on Thursday January 11th, taken from my office with my crappy digital camera:
(Also note the view, and understand why I am not in danger of taking up residence in California with the rest of the CV crowd anytime soon.) The comet is to the left of the street light, about 1/3 of the way from the right of the image, as you can see in this close-up:
It’s a stubby sort of comet, and not particularly dramatic compared to Comet Hyakutake, whose tail stretched a significant fraction of the way across the sky. I was at an observatory in Chile when that one was up, with nice dark skies. Absolutely spectacular.
While Comet McNaught is not much to look at in my crappy digital photo, it’s amazing one can see it at all. As the photo shows, the comet is sitting right on the western horizon, which implies that it’s close to the Sun. However, it’s difficult for such objects to be seen, since light scattered from the Sun swamps all but the brightest objects. In other words, you can’t see stars in the day time (especially in a well-lit metropolis like Seattle). The fact that we can see Comet McNaught means that it must be very bright indeed. (Note that overcoming the difficulty seeing stars in the daytime was at the root of Eddington’s 1919 test of General Relativity. The idea was to search for the deflection of stars’ positions by the mass of the Sun. However, you can’t see stars when they’re close to the Sun. Unless there’s a total eclipse. Which there was in 1919. Clever.)
On the other hand, McNaught’s brightness is not unrelated to its location. Solar radiation (made of photons and charged particles) is responsible for producing the tail, so when a comet approaches the Sun, the flux of solar particles increases, and the tail becomes brighter. Also contributing to Comet McNaught’s brightness is that it’s probably making its first and only trip into the solar system — McNaught’s orbit is parabolic, indicating that the comet is not gravitationally bound to the solar system, unlike bound, repeating comets like Halley. McNaught probably started out in the extended cloud of debris left over from the formation of the solar system (known as the Oort cloud — yup, same Oort), and was then kicked into the inner solar system by an interaction with something else. Since McNaught is taking its first trip in, it had plenty of material left for setting off a nice juicy tail. However, when finished, it will fling right back out into interstellar space, never to be seen again.
Now, while all of the above is impressive, the most impressive thing about Comet McNaught was that I spent a week at a meeting of several thousand professional astronomers right before this picture was taken, and nobody mentioned it! Nobody! I wandered out of a colloquium with some of my collaborators, and bumped into a UW astronomy undergrad clutching a pair of binoculars. He said “Hey! If you come over here you can see the comet!”, and my collaborators and I looked back and forth at each other and said “What comet?” like a bunch of dumbasses. Now that’s an impressive display of academic buffoonery.
P.S. I hope I don’t get kicked off for saying “dumbasses”.
January 16th, 2007 at 1:33 am
I tried to see the comet at sunset over the weekend, but found out that the Santa Cruz Mountains were in my way. I missed the comet, but who’s to say who has the better view day to day!
January 16th, 2007 at 1:40 am
I didn’t hear anyone talking about it at AAS either, but I did get some email about it. It really wasn’t much in the news until right about the end of the meeting. There was some talk in December that when it came back in January from being too near the Sun it might be really bright, but you know how comets are (I suppose you could say they’re mercurial).
January 16th, 2007 at 1:54 am
Clouds are horrible; I’ve yet to see it and am worried I’ll miss my chance!
I remember Hyukatake though, as it was my first “real” comet.* I was ten years old and my dad took us all out to the countryside, and in hindsight that was what first set me down a road to learn astronomy and physics. I remember that night being amazed that anyone could possibly learn all the stars well enough to spot an imposter among them, and realizing I could do so less than five years later…
*I was born in January 1986, so my dad made sure to hold me up to “see” Halley’s Comet a few months later when it came around. Of course I don’t remember this, but with a little luck I will be one of few people to see it twice when 2061 comes around.
January 16th, 2007 at 2:00 am
It is good to see the impressive picture. In particular the night scene is beautiful.
January 16th, 2007 at 9:55 am
[…] links « Comet McNaught […]
January 16th, 2007 at 10:48 am
Space weather has a billion pictures by amateurs around the world. www.spaceweather.com
I took a few too:
http://www.philipdowney.com/weblog/2007/01/comet-mcnaught-january-10-2007.html
January 16th, 2007 at 11:13 am
I have similar experiences. Having heard of the comet from some of my amateur friends, I had been trying to see the comet for a week without any luck, except for a brief, though spectacular, glimpse through the car window just when it was about to set below the horizon one night (for some reason, clouds always came to cover the south-west sky by the sunset). Being a bit frustrated already, last Friday I asked my astronomer friend at the department if he had had any luck. To my surprise, he hadn’t even heard of the comet! Seems like it’s best to rely on amateur stargazers when one wants up-to-date information about what is going on in the sky…
(I did finally get a proper view of the comet as well on Friday afternoon when the sky remained clear, albeit the cost was bitter coldness, temperature sank down to -35 C. When there is a comet to be seen with a naked eye, one just must see it…)
January 16th, 2007 at 11:43 am
I heard a few comments about it at the AAS meeting — enough to make me think, “What bright comet?” and go look for it on the web. So we aren’t completely hopeless.
Welcome, Julianne — good to have you here!
January 16th, 2007 at 11:57 am
JoA: if you want to see the comet, take a short ride to Half Moon Bay…
January 16th, 2007 at 11:58 am
PS to JoA: Don’t forget your tripod this time!
January 16th, 2007 at 12:37 pm
I’m not buying it - that can’t possibly be Seattle as there aren’t any clouds in the sky.
January 22nd, 2007 at 6:40 am
we saw it from sunbury australia victoria and it was beautiful and shinning throughout the sky!!
its a must see
once in a life time
“love ya all”
January 22nd, 2007 at 1:22 pm
I’m jealous! Glad to hear that it’s still putting on a show in the south.
PS. Lots of great photos over at Clifford’s. Check out the links in the comments as well.
January 23rd, 2007 at 3:09 am
is there any way we can see this comet as brightly here in Asia? i was thinking that i have seen it last Friday (i live in the Philippines, a little north of the equator) bu ti thought i was just imagining things. i thought i saw some faint comet.
lucky guys in the South.
January 23rd, 2007 at 3:35 pm
I live in Lismore, NSW, Australia. I have just taken some pics of comet McNaught. Although I have only a digital camera, it looks great in the evening sky. I can upload a couple to you if it would be of benefit.
GarryM
January 27th, 2007 at 5:19 am
I couldnt take my eyes of it for about the last 6 nights. The first night it was so bright that I could see a beautiful amber glow and the tale as it arched across our milky way here in New Zealand. One of the best memories I will ever have.
January 28th, 2007 at 9:12 pm
i was stuck in the US during the cloud covered ice storms, but luckily made my way south of the equator just in time to catch mcnaught! the waxing moon was bright enough last night that i managed to get myself in the shot as well….
http://www.pbase.com/astropixie/image/73655477
January 29th, 2007 at 12:25 pm
What a great portrait to have! Thanks for all of the reports from down under…