General / Off-Topic Is Betelgeuse going to blow up?

No, that's not how this works. To be the size of the full Moon at that distance, the actual explosion area would have to be not massive, but absurdly ludicrously humongous. No, it will be brighter than a full Moon, yes, larger or large as, not.
 
No, that's not how this works. To be the size of the full Moon at that distance, the actual explosion area would have to be not massive, but absurdly ludicrously humongous. No, it will be brighter than a full Moon, yes, larger or large as, not.
Presumably the resulting nebula could end up the same apparent size as the moon..... After it's had millions of years to expand, and for the moon to retreat even more from the Earth...
 
No, that's not how this works. To be the size of the full Moon at that distance, the actual explosion area would have to be not massive, but absurdly ludicrously humongous. No, it will be brighter than a full Moon, yes, larger or large as, not.
The explosion area of a supernova just some 600LY away will appear to be absolutely humongous, because it will be for a star this massive :)
 
No, that's not how this works, that's not how any of this works 😅...a supernova won't instantly become an object some light years in diameters against any possible law of nature, just because is a very very big explosion. Current Betelgeuse diameter is loosely estimated at something between the size of Mars and Jupiter's orbit. Not Jupiter, Jupiter's orbit. When it'll go nova, the bulk of the star mass will collapse again before rebounce, the actual release of energy in the optical spectrum will happen when the star will be a lot smaller than it currently is. And currently, it can be barely resolved as nothing more than a bunch of pixels by the most advanced instruments humanity has been able to devise until now.

Magnitude and angular diameter are related, but not necessarily proportionally.
 
No, that's not how this works, that's not how any of this works 😅...a supernova won't instantly become an object some light years in diameters against any possible law of nature, just because is a very very big explosion. Current Betelgeuse diameter is loosely estimated at something between the size of Mars and Jupiter's orbit. Not Jupiter, Jupiter's orbit. When it'll go nova, the bulk of the star mass will collapse again before rebounce, the actual release of energy in the optical spectrum will happen when the star will be a lot smaller than it currently is. And currently, it can be barely resolved as nothing more than a bunch of pixels by the most advanced instruments humanity has been able to devise until now.

Magnitude and angular diameter are related, but not necessarily proportionally.
Surely outer layers that will be thrown off by the collapse of the core should be visible from this close.
According to this, speed of those gasses can reach up to 50 million kilometers per hour. Which is some not insignificant fraction of a speed of light.
With resulting cloud being over 1Ly in diameter for supernovae Betelguese might become. It would take some time, but still :)
If those lads back in 1054 saw something incredible from 10 times as far away, surely we would too ;)
 
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No, that's not how this works, that's not how any of this works 😅...a supernova won't instantly become an object some light years in diameters against any possible law of nature, just because is a very very big explosion. Current Betelgeuse diameter is loosely estimated at something between the size of Mars and Jupiter's orbit. Not Jupiter, Jupiter's orbit. When it'll go nova, the bulk of the star mass will collapse again before rebounce, the actual release of energy in the optical spectrum will happen when the star will be a lot smaller than it currently is. And currently, it can be barely resolved as nothing more than a bunch of pixels by the most advanced instruments humanity has been able to devise until now.

Magnitude and angular diameter are related, but not necessarily proportionally.
This is all correct afaik , and it is good to read.

The moon sized object that I read about is the bright nebula of thrown off gas. That will take time to form, certainly.

However even that is speculative as the star is doing many weird things we cannot explain, like spinning way too fast, and our models do not match it, so predictions are unreliable.
 
Just take a look at Barnard's Loop. It is believed to have been created approximately 2 million years ago. It is approximately 600 arcminutes in the sky. This is a measure of it's size. The moon is 31 arcminutes in size. This means the moon is about 20 times smaller than Barnard's Loop. That means that in 1/20th of 2 million years it was the size of the Moon. Therefore, ( 2,000,000 / 20 = ) 100,000 years is how long it took to become Moon sized. Betelgeuse is about half the distance, so... roughing the math again, 50,000 years before (if) it's nebula reaches that same size.

Anyone feel free to correct me if I got that wrong, not an expert here, but that's how I understand it.
 
Just take a look at Barnard's Loop. It is believed to have been created approximately 2 million years ago. It is approximately 600 arcminutes in the sky. This is a measure of it's size. The moon is 31 arcminutes in size. This means the moon is about 20 times smaller than Barnard's Loop. That means that in 1/20th of 2 million years it was the size of the Moon. Therefore, ( 2,000,000 / 20 = ) 100,000 years is how long it took to become Moon sized. Betelgeuse is about half the distance, so... roughing the math again, 50,000 years before (if) it's nebula reaches that same size.

Anyone feel free to correct me if I got that wrong, not an expert here, but that's how I understand it.
All seems right. I just don't know if gas just keep expanding at the same rate. Only because gas has initially such high velocity doesn't mean it keeps it. It probably decelerates as some gravitational pull from the star's remnant is still applied. Or it could be negligible. Obviously just a forum speculator here :)
 
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Right after a supernova 650 ly away, the nebula will be small but very bright. I think it would be outshone by the glow of the exploding star, but the Crab Nebula is still expanding after 6500 years. So much that you can see it on pictures taken a few years apart.

Here are some interesting news about my favorite star from my favorite astronomer:


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It will take some measly 32 thousand years for cloud to reach 1.5Ly in diameter at 50 million kilometers an hour expansion. Or half of that? I suppose it expands outwards in all directions?
 
Just to +1 that the s/nova itself will probably be visible to the naked eye, but it'll be a pinprick/very bright star. The nebula formed will indeed be bigger than the moon in angular diameter BUT will be significantly dimmer, much like the crab nebula is today.

I'n not sure anyone has predicted how the nebula will look, but even though it's close, galactically speaking, it'll still take significant (= more 50years ) time to expand to the moon's size.
 
All seems right. I just don't know if gas just keep expanding at the same rate. Only because gas has initially such high velocity doesn't mean it keeps it. It probably decelerates as some gravitational pull from the star's remnant is still applied. Or it could be negligible. Obviously just a forum speculator here :)
The thing that will happen will probably be more interesting than that. We'll see an expanding cloud of gas/debris, but it won't just be the matter actually expanding away from the explosion. The first thing we'll see will be the matter already being ejected over the years/centuries/eras, progressively illuminated by the "photon wave" of light from the explosion, as it progressively travels away at the speed of light. Since that light will bounce and be reflected by matter along the way, we'll also see the light coming from that matter, and arriving at different times, potentially giving the impression of a shockwave traveling faster than the speed of light. Of course matter will stil be expanding at the same time at a slower speed and still emitting its own/reflected light, so TL;DR, we'll see funny stuff for centuries to come.

To see funny stuff like that already happening in real time, google "V838 Monocerotis light echo".

 
Betegeuse is 700 light years away. To be the apparent size of the moon in the sky (an angular diameter of about half a degree) , it would need to be 6 light years across.
Rest assured, that if it goes supernova, you'll find me glued to my old Schmidt–Cassegrain telescope. I'd miss Betelgeuse, but having the chance to see it would probably beat anything else, including reproduction.
 
The thing that will happen will probably be more interesting than that. We'll see an expanding cloud of gas/debris, but it won't just be the matter actually expanding away from the explosion. The first thing we'll see will be the matter already being ejected over the years/centuries/eras, progressively illuminated by the "photon wave" of light from the explosion, as it progressively travels away at the speed of light. Since that light will bounce and be reflected by matter along the way, we'll also see the light coming from that matter, and arriving at different times, potentially giving the impression of a shockwave traveling faster than the speed of light. Of course matter will stil be expanding at the same time at a slower speed and still emitting its own/reflected light, so TL;DR, we'll see funny stuff for centuries to come.

To see funny stuff like that already happening in real time, google "V838 Monocerotis light echo".

That stuff is interesting, but too far away :) I'm hoping for a mini little black hole in place of Betelguese, although not highly likely from what I understand. It would have to retain like half of it's mass in the core when it goes boom to collapse back to black hole. Otherwise it'll just be another boring neutron star.
 
That stuff is interesting, but too far away :) I'm hoping for a mini little black hole in place of Betelguese, although not highly likely from what I understand. It would have to retain like half of it's mass in the core when it goes boom to collapse back to black hole. Otherwise it'll just be another boring neutron star.
Perhaps we already have a black hole much closer than Betelgeuse:


It's an interesting hypothesis. I haven't followed the Planet Nine thing, not having had access to a telescope for years, but if amateur astronomers are able to find exo planets, and astronomers back in 1847 could calculate the position of Neptune based on the not completed orbit of Uranus, it can't be impossible to find a tiny black hole in our own solar system.
 
Perhaps we already have a black hole much closer than Betelgeuse:


It's an interesting hypothesis. I haven't followed the Planet Nine thing, not having had access to a telescope for years, but if amateur astronomers are able to find exo planets, and astronomers back in 1847 could calculate the position of Neptune based on the not completed orbit of Uranus, it can't be impossible to find a tiny black hole in our own solar system.
It's too interesting to be true :) Probably just some rogue planet passing by, or it got captured and decided to hang around.
 
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