Thread: Stargazing anyone?

This would be mad cool to watch, what do you think Weedman? (buddy of mine showed this to me)

Here's Betelgeuse. It's a star. A really big, prominent one. If you go outside and take a look at the constellation Orion, it's his right shoulder.



That might not look like much, but it is. There are only about a dozen stars in the universe that can be imaged as a disc, instead of a point, on even the largest telescopes. We can see sunspots on it. This star is staggeringly enormous, it's about 1000 times the diameter of the sun. If you took Betelgeuse and overlaid it on the Sun, the outer edge of the star would be somewhere out by the orbit of Saturn. It is the ninth-largest star in the entire universe

It's also old. Not in absolute terms, it's only about 8.5 million years old. But in terms of stellar lifetimes, it's a doddering old fart. It's a red supergiant and is way off the main sequence. That means that it's already burned up its supply of hydrogen, and is currently burning helium and heavier elements, working its way up to iron. And when stars start accumulating iron in their cores, they're not long for this universe; the fusion of iron is endothermic, so once iron starts building up there's no more internal outward pressure to counter gravitational collapse, and when that happens we get a nice big Type II supernova, with a neutron star or black hole left over. Beltelguese

It's been suspected for a while that Betelguese is an excellent candidate for a supernova at some time within the next few thousand years. Supergiants don't last long, because they're so huge. More graviational pressure means the fusion reaction runs at a higher rate, so the most massive supergiants can burn through their hydrogen in under a million years. So 8.5 million years is pretty old for a supergiant. And Betelgeuse has been *shrinking*, which is a death throe. It's been shrinking, in fact, since 1993; in June of last year, it was only 85% as big as it was back then. And the rate of shrink has been accelerating.

Well, now there's a new rumor, supposedly from the Mauna Kea observatory, that the rate of shrinkage has gotten so fast that the star isn't round anymore. Since a star spins, conservation of angular momentum means that when it undergoes gravitational collapse, it'll happen faster along the polar axis than along an equatorial one. But it would have to be *very* fast for this to show up as a distinct oblateness.

If this rumor is true, then it's likely that that timeframe changes from "within the next few thousand years" to "within the next few months. Or weeks." You could walk outside tonight and see a star in the very final stages of still being a star (well, if you're in the right hemisphere). And if it blows, it will be spectacular; the best-observed supernova in history occurred back in 1054, and that one was visible, *in broad daylight*, for 23 days, and visible at night for about two years. And that star was 6300 light years away, not 600. At the very outside, this could be twice as bright as a full moon.

Don't worry, it's too far away to hurt anything. But man, would that be incredible to witness.

(copy-pasted from SA)

what do I say? I say this is a baby compared to this:

1:42 says it all

So this star, Canis Majoris, being so big, it only lives for a few million years. It is at about 4900ly away, so it's probably collapsed into a black hole already. it's so big, that going hypernova is impossible. even the "small" supernova state is not gonna happen. it will just silently collapse directly into a black hole, in less then a few seconds. Don't forget that Betelgeuse is a red supergiant, this being the reason why it's so big in size, a star at the end of it's life, just like our sun will be. But while Betelgeuse is about 20 solar masses, VY CM is above 300, so big that will never go in the usual "giant phase" like Betelgeuse did. and no, it doesn't reach Saturn, it hardly reaches Jupiter's orbit. CM itself hardly reaches Saturn's orbit, if it's center was placed where the Sun is

yes, but what i meant was... will you be outside for the next couple weeks watching for this?

lol, why weeks? a few minutes and you already found it on the night sky at least Betelgeuse

ummm... did u read the post?

yea, and don't worry, it's not gonna happen in our lifetime before any star turns supernova or changes life stages, there are clear sign that astronomers can use and predict exactly when it's gonna happen. if it would go supernova in "a few month", it would be engulfed by gas and dust from the pre-supernova outbursts. but it isn't

damn.. there go my dreams of... well... umm... anyhow. it would be pretty cool.


the source of that post wasn't the most reliable one around and i figured you'd have something to say about it. (i cba to research stuff like that)

yea, it would be awesome to see a small Sun on the "night" sky for a few weeks huh?

ok if our sun was replaced with deneb then paper and wood would catch on fire instantly and metal would melt after 10 minutes and the world would catch on fire in 30 inutes and then explode