Some of my friends have been posting on Facebook about the “imminent” implosion of Betelgeuse - supposed to happen in 2012 (although most credible articles I’ve read say that no one knows exactly when the supernova will happen).
Here’s my dumb question - Betelgeuse is 640 light years away. So that means even if a supernova does happen, we won’t see it until 640 years after it happens . . . right? So this supernova could have already happened? I may be asking a very obvious question, but none of the articles I’ve read address this question at all.
Right, the speed of light is an absolute limit, you’re always seeing light emitted 640 years ago.
So sure, it could have happened yesterday but we won’t know it for 640 years - but forget any nonsense about it being “supposed to” go supernova in 2012, scientific predictions on when it might happen are on the order of any time in the next million years.
The predictions I’ve heard are much more imminent: We’d see it any time in the next thousand years or so. Which means it’s quite plausible that it might have already gone and we’re just waiting to get the news. Incidentally, it’s the only star visible to the naked eye for which this is plausible.
Also note that, while a Betelgeuse supernova would look really freakin’ impressive, it would not be an end-of-the-world scenario (and probably wouldn’t have any real disastrous effects at all-- Worst case, it might cause eye damage if you stared directly at it, like the Sun). So tell your friend not to bother trying to tie it to the whole Mayan thing.
No credible astronomer thinks we can predict when Betelgeuse will go supernova down to the year.
Yes, Betelgeuse could have already gone supernova, and we just don’t know about it yet. We will not know until 640 years after the supernova actually happens.
As an aside, I can’t decide whether if the awesomeness of seeing Betelgeuse go supernova in my lifetime would be worth Orion looking “wrong” every time I saw it afterwards.
I read recently (no cite) that a supernova in our galaxy would produce enough radiation to sterilize planet earth. Also, the extinction of the dinosaurs may not have been due to meteor hit, but was actually caused by a supernova.
So, if this is true (an I admit I don’t have a clue), then put on your dark glasses and enjoy the thirty seconds or so that you will be alive to enjoy the show.
Nah, there have been supernovae in our galaxy during human history. The Crab Nebula is the remnant of a star in Taurus that went supernova in 1054. Chinese astronomers saw it and called it the “guest star,” and it was supposedly pretty spectacular, bright enough to see even in daylight. There was an even brighter one in 1006.
According to estimates described here of its maximum brightness in such an event, I doubt if you’d be able to see the rest of Orion, or any other stars at all with the exception of the Sun. The full moon is bad enough at washing out most of the sky, even in areas with a dark sky, and the Betelgeuse supernova will be brighter still. But it would only be for a few months in any event.
Link no work. By Orion looking “wrong” I don’t mean so much during the supernova, I mean forever missing a star after the supernova dims - missing a shoulder, so to speak. I don’t know, though, sounds pretty awesome.
Yes, a gamma-ray burst from a nearby star would be extremely nasty, though it probably wouldn’t instantly sterilize the planet like some doomsayers are claiming. However, gamma ray bursts only occur in a very narrow stream (from the poles of the star) and Betelgeuse isn’t pointing at us in any way for the gamma rays to affect us.
By Orion looking “wrong” I don’t mean so much during the supernova, I mean forever missing a star after the supernova dims - missing a shoulder, so to speak. I don’t know, though, sounds pretty awesome.