As if Google Earth was not already a great waste of time.
Google Earth now has the Space view (available in the latest download) just press the space icon and then see the night sky in unprecedented detail, I decided to take a stroll around Orion an did a close up on Betelgeuse.
A few years ago, I asked in the Straight Dope if there was something to worry if this star did go supernova. Even The Bad Astronomer mentioned that it was going to be a spectacular sight but because the star was about 600 light years away it was determined that Earth would barely be affected by the explosion. Then on Google Space I notice the link to an astronomy site and… did something change? Now even Wikipedia is reporting that the latest SIMBAD satellite query showed that Betelgeuse is actually 427 light-years away from Earth.
Mmm.
Should we worry now? :dubious:
(Not that it will be likely go supernova now, but should our descendants worry?)
About the only way I can see the impending supernova causing us trouble is if one of Betelgeuse’s poles is lined up on us, and we receive the brunt of a gamma ray burst.
Still, I keep an extra jar of bug juice in the garage, just in case.
Determining distances to stars is a tricky business. But we think we’re safe if a supernova of the type that Betelgeuse could become happens more than 100 light-years away (unless we’re in the path of a gamma ray burst from it), so either way, we think we’re still OK.
Here’s something that I’ve been wondering about for a while.
Let’s suppose that a nearby star went supernova and we were caught in the blast radius. Would we even know about it? Would the light from the event reach us before the blast material does?
When you see distances to stars printed - no matter where - bear in mind they’re not quite wild-ass guesses, but they’re pretty close. Except for the very nearby stars, those distances are extremely rough estimates.
If I recall correctly, there is, in fact, NO star close enough to Earth that can possibly go supernova that could harm life here.
I certainly don’t think we should worry. If it’s a significant and serious risk, then maybe you should try to finish that book you’ve only been dipping into, but worrying isn’t going to stop it happening, or alter its severity if it does happen.
It would have to have exactly no mass to travel at the speed of light. (There’s a short story by Isaac Asimov where this is a plot point)
It would have to have imaginary mass (ie, involving the square root of -1) to travel faster than light.
Neutrinos have mass (at least that’s the current scientific opinion), so they travel slower than light. They managed to reach us from Supernova 1987A before the light did because the process in the supernova that emits them happens before the process that emits the light. They had a head start, in other words. This isn’t the case for the supernova remnant stuff, at least not AFAIK (IANAsupernova expert).
How did you know? Oh wait, you mean reading it, not writing it.
IIRC on the last thread there was talk that if the distance was less than 500 light years away then we have to worry not only about gamma rays but also x-rays. However, at that distance the damage would be limited to satellites and some roasted astronauts. So it is not that I’m worrying much for humanity, but the problems some could encounter when it happens.
As I noticed that Betelgeuse is closer than 500 light years, then I wanted to investigate how much more then would Betelgeuse going supernova could affect us.
Nope. The Sun’s too small. It will kill us in other ways, just as effectively.
I’m too lazy to compute what percent of Betelgeuse’s mass would reach us as a part of the surface of a sphere with a radius of 427 LY. Would we even be able to detect it?
It can’t go supernova. To be able to go supernova, a star has to either be at least eight or nine times as massive as the Sun, or be a white dwarf and have a mass of at least 1.4 solar masses.
White dwarfs generally get a mass of more than 1.4 solar masses from a companion star that has expanded to a red giant. The outer layers of the red giant aren’t held very tightly, and if the white dwarf is close enough, it might be able to pull those layers onto itself. When the white dwarf gets a mass greater than about 1.4 solar masses (depending somewhat on its rotation), it collapses and creates a Type Ia supernova.
There actually is a star within 10 light years that may eventually become a Type Ia supernova- Sirius B, the white dwarf companion of Sirius. But Sirius B isn’t gaining mass now, as far as we can tell- it won’t until Sirius A becomes a red giant. (A stellar collision could probably do it, but that’s incredibly unlikely) We think that, by the time Sirius B could go supernova, it will have moved far enough away from us so as not to be a problem.
So supernovas in the immediate stellar neighborhood are no concern right now, but given the potential at Alpha Canis Majoris, in astronomical time scales, it could be a Sirius problem?
