"Since its rotational axis is not toward the Earth, Betelgeuse's supernova would not cause a gamma ray burst in the direction of Earth large enough to damage its ecosystem even from a relatively close proximity of 520 light years."
Also it would take 520 years to get here anyway...
But I suppose that makes no difference because the first we'd know about it would be the gamma burst. What we're really discussing here is "Has Betelgeuse already gone Boom?"
Yes it was. [nobelprize.org] From the linked page:
The good agreement between the observed value and the theoretically calculated value of the orbital path can be seen as an indirect proof of the existence of gravitational waves.
The Nobel Prize was for discovering a binary pulsar that can be used to test GR. Indeed such systems have been shown to lose energy in a manner consistent with GR predictions of gravitational waves. However that does NOT mean that gravitational waves have been discovered. All it means is that whatever mechanism they have to lose energy is consistent with gravitational waves. Until we actually detect gravitational waves on Earth we cannot be certain that they exist.
And when a gravitational wave detector gives us a signal, we also "only" know that whatever mechanism caused that signal is consistent with GR predictions of gravitational waves. And the same is true of every other way we could test them. Note that a scientific fact is never absolutely proven, any scientific "proof" is nothing but sufficient evidence to dismiss all known reasonable alternatives.
So unless there is another reasonable theory correctly predicting the energy loss of the pulsars without gravitati
Assuming they exist at all...which has not yet been proven.
And assuming that our assumption that they travel at the speed of light is also correct. Given our history of wrong assumptions I would assume the probability is low...
They are a prediction of GR - they cannot travel faster than light. If we discover that they do then they are not the gravitational waves that are predicted but something else (and far more exciting!).
Assuming they exist at all...which has not yet been proven.
It's incredibly unlikely that they don't, since otherwise the entire universe doesn't work and is just a movie show put on by the Illuminati to keep us preoccupied while they take all our money and bring the antichrist. I blame Prince Philip. He's Greek. And the Queen is German.
No, no, no, the first way to tell if a star has already gone supernova is by the change in graviton waves.
I know you are trying to be funny but if there are gravity waves (possibly transmitted by gravitons) they would still arrive at the speed of light much like the visible and other EM radiation with very little lead time, if any. These are predicted by General Relativity and as such cannot violate relativity's golden "no information faster than light" causality rule. Even if the current gravity wave detectors were sensitive enough to detect any gravity waves it would be an after the fact detection since it t
The fact that light from the core takes a lot more time to reach the surface than from the surface to the earth has a completely different reason.
In fact, neutrinos aren't massless which means they are slower than light. The only reason the neutrinos arrived first is because of the way supernovas work. The neutrinos get emitted as soon as the core collapses but the first visible light only appears as soon as the shockwave from the collapse gets to the surface.
p>But a serious question: Over distance, wouldn't the visible light catch up to the neutrinos?
Sure, but over what distances are we speaking here? A neutrino created in a supernova would go about a trillionth of a meter per second slower than light, so even if they did a race across the universe( 80 billion lightyears), the neutrino would only be 60 km behind!
Neutrinos arrived about three hours before visible light
True - but unless things have improved dramatically since I last heard a talk from LIGO it would need to arrive days, weeks or even months in advance! Gravity wave detectors measure vibrations and have to have an incredibly complex understanding of their noise. This takes time.
from what I understand neutrinos are what to look for as they supposedly travel faster than light but can't go any slower. There are giant detectors in old salt mine a thousand feet under ground (filled up salt mines) looking for just one or two a month that might happen to crash into water molecules on their way thru the planet.
The question is would it be possible to detect enough of them to be sure it was from a specific place in space? The second question is how fast do they really go, if you have no oth
We believe we have a pretty good idea about a star's life cycle [wikipedia.org], so to determine when Betelgeuse will "go boom", we need to figure out what element it is mostly fusioning at the moment. If it's hydrogen or helium or even oxygen, we're pretty safe from a boom, but if it's silicon we might have to look out for a pretty light show in the not distant future.
Either way, it shouldn't come as a surprise, and that we'd first know it from the gamma burst is most likely wrong.
...so to determine when Betelgeuse will "go boom", we need to figure out what element it is mostly fusioning at the moment.
This is hard to do. Although I'm a particle physicist, not an astronomer, I say some recent articles about a star "unexpectedly" exploding despite its hydrogen rich outer atmosphere. What you need to know is what elements are being burnt in the core which (apparently) are not necessarily the elements are present in the outer atmosphere of the star.
The stellar spectrum would only tell you what is present in both the outer layers of the star and the "atmosphere" that surrounds the star.
We can identify the elements of the Sun in this fashion, where both incandescent gasses (glowing because they are hot) and absorption of the light takes place. See also: http://en.wikipedia.org/wiki/Spectrum_analysis [wikipedia.org]
What we do know, however, is that Betelgeuse is no longer a main sequence star on the HR Diagram [wikipedia.org] and is clearly a dying star. The question here is to dete
Also it would take 520 years to get here anyway...
The thing about distances measured in lightunits, causality propagates at that same speed. So if we see it happening now, for us, causally (not casually) speaking, it is happening now.
It's just futile for us to try to do anything to stop it, because it is impossible for our reaction to have an effect on it for another 520 years (like sending a radio signal saying, "Frood, it appears that your star's just exploded! Are you all right?").
Nova Post! (Score:4, Funny)
Boom!
Re: (Score:3, Interesting)
Seriously - If it goes supernova we should be a bit worried because it's close enough to drown us with radiation.
If that happens all our petty bickering on this planet will seem insignificant.
Of course - it's not certain that the radiation will be strong enough to kill off all life, but things will probably change a lot.
Re: (Score:5, Informative)
http://en.wikipedia.org/wiki/Betelgeuse [wikipedia.org]
Re:Nova Post! (Score:2)
Also it would take 520 years to get here anyway...
But I suppose that makes no difference because the first we'd know about it would be the gamma burst. What we're really discussing here is "Has Betelgeuse already gone Boom?"
Re: (Score:3, Funny)
because the first we'd know about it would be the gamma burst
No, no, no, the first way to tell if a star has already gone supernova is by the change in graviton waves.
Just need to finish figuring out how to detect those... maybe if we supply more power to the lateral sensor array...
Re: (Score:3, Funny)
Actually, thinking about this rationally, I'm sure the Jedi could detect it ahead of time as planets in it's wake are destroyed.
Re: (Score:1)
Only if they exist (Score:2)
Nope, gravitational waves travel at the speed of light.
Assuming they exist at all...which has not yet been proven.
Re: (Score:3, Informative)
Yes it was. [nobelprize.org]
From the linked page:
Re: (Score:2)
That's awesome. They should win a Nobel Prize for that.
Oh wait....
No they were not (Score:2)
Re: (Score:1)
And when a gravitational wave detector gives us a signal, we also "only" know that whatever mechanism caused that signal is consistent with GR predictions of gravitational waves. And the same is true of every other way we could test them. Note that a scientific fact is never absolutely proven, any scientific "proof" is nothing but sufficient evidence to dismiss all known reasonable alternatives.
So unless there is another reasonable theory correctly predicting the energy loss of the pulsars without gravitati
Re: (Score:2)
And assuming that our assumption that they travel at the speed of light is also correct. Given our history of wrong assumptions I would assume the probability is low...
Re: (Score:2)
Re: (Score:2)
Assuming they exist at all...which has not yet been proven.
It's incredibly unlikely that they don't, since otherwise the entire universe doesn't work and is just a movie show put on by the Illuminati to keep us preoccupied while they take all our money and bring the antichrist. I blame Prince Philip. He's Greek. And the Queen is German.
Re: (Score:2)
At what altitude?
Re: (Score:2)
Gravitational waves, by definition, are always at sea level.
Re: (Score:2)
Gravity Waves (Score:2, Informative)
No, no, no, the first way to tell if a star has already gone supernova is by the change in graviton waves.
I know you are trying to be funny but if there are gravity waves (possibly transmitted by gravitons) they would still arrive at the speed of light much like the visible and other EM radiation with very little lead time, if any. These are predicted by General Relativity and as such cannot violate relativity's golden "no information faster than light" causality rule. Even if the current gravity wave detectors were sensitive enough to detect any gravity waves it would be an after the fact detection since it t
Re: (Score:3, Interesting)
The fact that light from the core takes a lot more time to reach the surface than from the surface to the earth has a completely different reason.
In fact, neutrinos aren't massless which means they are slower than light. The only reason the neutrinos arrived first is because of the way supernovas work. The neutrinos get emitted as soon as the core collapses but the first visible light only appears as soon as the shockwave from the collapse gets to the surface.
Disclaimer: I'm not yet an astrophysicist, but I
Re: (Score:2)
>> I'm not yet an astrophysicist, but I did ace my cosmology exam yesterday
What does "50 ways to please your man." have to do with astrology?
But a serious question: Over distance, wouldn't the visible light catch up to the neutrinos?
Re: (Score:2)
p>But a serious question: Over distance, wouldn't the visible light catch up to the neutrinos?
Sure, but over what distances are we speaking here? A neutrino created in a supernova would go about a trillionth of a meter per second slower than light, so even if they did a race across the universe( 80 billion lightyears), the neutrino would only be 60 km behind!
Re: (Score:2)
Now I'm no astrophysicist, so I cannot tell if any of those possibilities applies.
Why is it that when I read that, I imagined you saying it in an "aw shucks" Matlock style:
"Now, ya Honor.... I ain't one of them big city Astrophysicists...."
Re: (Score:2)
Neutrinos arrived about three hours before visible light
True - but unless things have improved dramatically since I last heard a talk from LIGO it would need to arrive days, weeks or even months in advance! Gravity wave detectors measure vibrations and have to have an incredibly complex understanding of their noise. This takes time.
Re: (Score:2)
from what I understand neutrinos are what to look for as they supposedly travel faster than light but can't go any slower. There are giant detectors in old salt mine a thousand feet under ground (filled up salt mines) looking for just one or two a month that might happen to crash into water molecules on their way thru the planet.
The question is would it be possible to detect enough of them to be sure it was from a specific place in space? The second question is how fast do they really go, if you have no oth
Re: (Score:2)
Neutrinos are not tachyons. Neutrinos appear to have some (small, non-imaginary) mass so they travel slower than light.
Re: (Score:2)
No, no, no, the first way to tell if a star has already gone supernova is by the change in graviton waves.
Joking aside, would that be true? Wouldn't pre- and post-nova mass be roughly the same (minus what gets converted to energy) with the same center?
Re: (Score:2)
An overall change in mass is not necessary to generate gravity waves.
Re: (Score:2)
We believe we have a pretty good idea about a star's life cycle [wikipedia.org], so to determine when Betelgeuse will "go boom", we need to figure out what element it is mostly fusioning at the moment. If it's hydrogen or helium or even oxygen, we're pretty safe from a boom, but if it's silicon we might have to look out for a pretty light show in the not distant future.
Either way, it shouldn't come as a surprise, and that we'd first know it from the gamma burst is most likely wrong.
Hard to do (Score:2)
...so to determine when Betelgeuse will "go boom", we need to figure out what element it is mostly fusioning at the moment.
This is hard to do. Although I'm a particle physicist, not an astronomer, I say some recent articles about a star "unexpectedly" exploding despite its hydrogen rich outer atmosphere. What you need to know is what elements are being burnt in the core which (apparently) are not necessarily the elements are present in the outer atmosphere of the star.
Re: (Score:2)
Re: (Score:2)
The stellar spectrum would only tell you what is present in both the outer layers of the star and the "atmosphere" that surrounds the star.
We can identify the elements of the Sun in this fashion, where both incandescent gasses (glowing because they are hot) and absorption of the light takes place. See also: http://en.wikipedia.org/wiki/Spectrum_analysis [wikipedia.org]
What we do know, however, is that Betelgeuse is no longer a main sequence star on the HR Diagram [wikipedia.org] and is clearly a dying star. The question here is to dete
Re: (Score:2)
Re: (Score:3, Insightful)
Also it would take 520 years to get here anyway...
The thing about distances measured in lightunits, causality propagates at that same speed. So if we see it happening now, for us, causally (not casually) speaking, it is happening now.
It's just futile for us to try to do anything to stop it, because it is impossible for our reaction to have an effect on it for another 520 years (like sending a radio signal saying, "Frood, it appears that your star's just exploded! Are you all right?").
Re: (Score:1)
> Also it would take 520 years to get here anyway...
I thought they detected this shrinking just now, not 520 years ago.