Is Betelgeuse about to go Supernova?

originally posted by: Arbitrageur
As Eros and Box of Rain said, what reaches us before the light in a supernova are the neutrinos, not because they travel faster than light, but because when the core collapses, neutrinos can pass right through the outer layers of the collapsing star while the photons can't, so it takes the photons (light) somewhat longer to leave the supernova.

Good clarification. So the answer is that we'll get a little bit of a warning, but maybe not enough to run outside and see the thing blow up like a firework. Which I suppose it's not going to do anyway because it will still take a little time for the explosion / expansion to get big enough to even see. So we'll get an announcement from astronomers, but then the actual explosion will slowly grow and be seen for years and years. Not like we're going to miss it, or anything.

originally posted by: Blue Shift
Good clarification. So the answer is that we'll get a little bit of a warning, but maybe not enough to run outside and see the thing blow up like a firework. Which I suppose it's not going to do anyway because it will still take a little time for the explosion / expansion to get big enough to even see. So we'll get an announcement from astronomers, but then the actual explosion will slowly grow and be seen for years and years. Not like we're going to miss it, or anything.

Astronomers have an alert system to let other astronomers know about significant events they may want to observe.
I don't know if the neutrino signal will give them enough time to aim any telescopes, but after the neutrinos, apparently the star exterior may still be intact while the core is collapsing, and the collapse shock wave can heat up the star giving off some ultraviolet for some hours, which we can't see with our naked eyes but astronomers might be able to detect it. So if astronomers see the UV increase with Betelgeuse, that could be a sign of the impending explosion, and we could get some warning to go see it visually when it explodes.

Ultraviolet Glow Betrays Impending Supernova

In the latest in a series of supernova firsts, scientists report in Science that they pinpointed a star that flared in the ultraviolet portion of the spectrum for several hours before blowing itself apart in a supernova. The researchers believe the finding represents the earliest visible sign of an imminent supernova—a surge in temperature as the expanding internal shock wave strains to break free of the star but has yet to shred it apart.