What Will the Betelgeuse Supernova Be Like – and Will It Hurt Us?

> "But either way, as stars go, [a few hundred thousand to a couple million years is] not a lot. Our own Sun will outlive multiple generations of such giants, and red dwarfs, the smallest stars in the universe, can stretch for trillions of years at a time. In fact, just a fun side note, red dwarfs live for so long that the entire universe isn't even old enough for them to start dying yet."

A little bit off base there.

The sun is going to eventually turn into a white dwarf. White dwarfs are indefinitely stable; our sun is going to stick around, in some form, for roughly 10^15 years as an energy-emitting body, and for far longer than that as a cold "black" dwarf. After some 10^1500 years, it'll probably turn into a lump of iron, as the only indefinitely stable isotope is 56Fe, and all other elements will eventually turn into 56Fe via quantum tunneling.

Our sun is going to change form, but it's among the longest-lived things in the cosmos.

Neutron stars also have no expiry date. Once they're stable, they barely even cool down. The only thing that can kill them is proton decay (not likely) or if they're in a busy neighborhood and absorb enough interstellar gas to push them into black hole mass territory. They're effectively eternal.

Anyway, it's nice that Betelgeuse isn't going to harm life on Earth.

> Estimates based on the mass of Betelgeuse, its rotation rate, the group of stars it was born with, and the amount of metals we can measure in the upper layers of its atmosphere, all suggest that it's somewhere in the neighborhood of a few hundred thousand years from now, it's going to go supernova.

Trivia: in astrophysics "metal" doesn't mean the same thing it means in most of the rest of science, engineering, or common use.

To an astrophysicist metal means "any element heavier than helium" which is all of them except for hydrogen and helium.

> What saves us from most supernova dangers is that as bright as they are, as much radiation as they pour into the universe, stars are really stinking far apart.

Speaking of local effects, in which regional English is "stinking" a common intensifier?

Off topic, but how pleasant to land on a fast-loading site without a bunch of battery & soul draining ads and social detritus

> When Beetlejuice goes off, it's going to be the show of a lifetime. But it’s not going to hurt us.

This got me confused for a second. I thought they were referring to some movie.

DID YOU KNOW... you can sign up to the SNEWS mailing list ( https://lists.bnl.gov/mailman/listinfo/snews-alert ) and get a few hours' email warning of a visible supernova, including but not limited to Betelgeuse? If you gate email from SNEWS to bast out to your pocket pager (I am using 1990s-speak here) ... and a bit of luck, you might have enough time to be star-gazing the first emergence of light with the naked eye. Or just as practically, find a good livestream to watch. Project homepage ( https://snews.bnl.gov/ ).

The global neutrino detector network is a 'first' for detecting supernovas from an event that arrives slightly-sooner-than-light. Gosh that seems strange to say, almost like a joke. Amazing times!

It is the ultimate low traffic mailing list and has no archives, because an alert has never been sent since its inception. Supernova 1987A WAS detected by the network 3 hours hours before, but they only realized it after the visible event occurred. They are prepared now, when a threshold of hits across detector sites is triggered, the automatic alerts will go out without delay or human involvement.