Please excuse my messed up quote. :smack:
Hey! I got the link right!
I know it is just science fiction, but Robert J Sawyer had this to say in his book Calculating God, about Betelgeuse going supernova:
How “true” is this? Would life truly become extinct on earth? Sawyer uses it as a possible premise for a mass extinction, like the one that killed off the dinosaurs.
Even if it is hugely exagerated, it’s still a good book 
Try reading this for some numbers on radiation damage from a supernova;
http://www.tass-survey.org/richmond/answers/snrisks.txt
there might be even more energetic events that are more damaging; gamma-ray bursters
and type III supernovae (hypernovae)
which may be the same thing
Referring to the statement about Betelgeuse, it’s well known it is a prime candidate for death. In fact, it may well be dead as we speak. I believe it is in the ballpark of 800-1100 light years from Earth - off the top of my head. So, the telegram informing us just hasn’t arrived yet. 
- Jinx
Many of the main stars comprising the constellation, “Orion”, are in the ballpark of 1300 light years away except for Betelgeuse at 470 light years and Bellatrix at 325 light years away.
Just to finish off the Betelgeuse topic, it would still be a point source, at least to naked-eye observation, despite being so bright (the star is already just barely resolveable to the Hubble and (I imagine) ground-based adaptive optics scopes). And a full moon is easily visible in daylight; a smaller and more “concentrated” object would be that much easier to see. It’s certain that, as a really big red giant, it’s going to supernova; the question is just when. My source for the “approximately 1000 years” figure is one of my undergraduate professors, who was studying it.
It has been suggested that supernovae might trigger mass extinctions, but the last paper I saw on the possibility specifically ruled out Betelgeuse as a candidate. Apparently, it’s far enough away, and the “terrain”, so to speak, between there and here will help as well. A gamma-ray burst, were it to occur close enough (and we’re not sure if there could be any close enough) would sterilize the planet, but only half the planet: A gamma burst only lasts for seconds, and the other side of the planet would be adequately shielded.
And I don’t know about rho Cassiopeia, but eta Carina is usually considered to be a sort of planetary nebula, meaning that it’s probably already done whatever it is that it’s doing.
IMO, people don’t give enough thought to an obscure star named Sher 25. It’s in the southern hemisphere, and is almost certainly going to go supernova in the next 20,000 years (scroll down about halfway on that page). Betelgeuse may take much longer than that.
Yeah, but who cares about Southern Hemisphere stars?
Hey wait a minute…
I’m jealous of astronomers in the Southern Hemisphere. They get to see cool things we don’t. The Magellanic Clouds, for instance. From my latitude I can’t even see the Centaurus star cluster.
Bad Astronomer, how were my math and assumptions?
Hi guys,
Year before in 2010, when I was lying over the water-tank of my house, it happened for me to see a star explode and go off in a straight line, fading away. I remember initially that star had no much light (say visibly 2mm in diameter), suddenly exploded with a flash of light ( around 5-7 mm ). And then it swiftly took a straight path before fading away… It was an
Ashwin? Ashwin? Speak to us, Ashwin! My God…the zombie aliens in the spaceship he saw have got him. They’re coming for us all! Run!
(Seriously - if it was a natural phenomenon, it sounds like a meteor. Real stars don’t behave like that.)
nm
I would be willing to bet that what you saw was an ‘Iridium Flare’(which is quite neat). ETA: the simulation at the wiki-link doesn’t do it justice.
You can predict them with this site.
If you’re looking for something less spectacular, you can see several stars “go out”. Variable stars can change considerably in magnitude, due to eclipsing, variation in size, or variation in magntude. It caused quite a stir when omicron ceti apparently disappeared in 1598, only to re-appear months later. After that, people looked for and found many more variable stars. Beta Persei (Algol) is an eclipsing variable star with a period of just under three days. The times of the minima are given every month in Sky and Telescope magazine.
Although the knowledge of such variable stars officially goes back to the disappearance and reappearance of omicron ceta and Holwarda’s 1638 book (which resulted in its other name, Mira), I’ve argued that the variability of Mira, Algol, Delta Cephei, and gamma Cassiopeia were known to the ancients.
Awesome site, KarlGauss, thank you! The other day I saw what I took for the biggest shooting star ever, but as it turns out it actually was one of those. Quite neat indeed.
I hate zombie stars!