LOLMSimon wrote:Perhaps the teacher could do it.pfrit wrote:Close is ~25 lightyears. If we were looking right at one of the stars poles, close could be as much as 1000~ lightyears. We aren't on Betelguise's pole. We aren't close. Before anyone says "But what if its axis changed and it pointed at us!!!", that really can't happen either. The law of conservation of angular momentum save us there. Really, it would be a very cool light show and thats about it. Much brighter than the crab nebula's supernova. Daytime shadows might even be possible. Might be dangerous to look directly at. I don't know if the pupil is large enough to focus the star at that distance.Skipjack wrote:Isnt there a chance for one of those gamma ray bursts? If one of those hits us from comparably nearby, we are toast.
Betelgeuse to Nova
What is the difference between ignorance and apathy? I don't know and I don't care.
Simon almost never posts. We have to encourage him as much as possible. Otherwise he will never post anything. I think you might suffer from a similiar lack of encouragement. Good Post, Kiteman.KitemanSA wrote:You are blessed with being easily amused. His quip elicited only a wry demi-smile from me.pfrit wrote:LOLMSimon wrote:Perhaps the teacher could do it.
What is the difference between ignorance and apathy? I don't know and I don't care.
Fortunately, it's not a hypergiant.
http://en.wikipedia.org/wiki/Doomsday_event
http://www.armageddononline.org/hyperno ... -star.html
http://en.wikipedia.org/wiki/Doomsday_event
http://www.armageddononline.org/hyperno ... -star.html
There was a GRB supernova detected from about 7 billion LY a couple of years back that was so strong it would have stood a fair chance of sterilizing its entire galaxy. I believe they finally determined we saw the radiation from a polar jet, about a hundred times stronger than the average output. Still, a beast, far beyond an ordinary supernova. Colliding galactic black hole stuff.
The Wikipedia article on Betelgeuse seems at least good enough for our discussion here. It claims the photosphere (which is huge, large enough to be seen as a disk in large telescopes) has been shrinking fast for the last 15 years,: "The average speed at which the radius of the star is shrinking over the last 15 years is approximately 210–219 m/s (470–490 mph)."
I don't know the speed at which the shock wave will travel, but it won't be anywhere close to the speed of light, and it won't arrive "a few years" after the explosion. Space is full of old shocks ... they cause significant effects (local compression of gas that triggers formation of new stars, etc) but they are not world enders at this range. We're in a gas-poor region and the shock will weaken here as a result.
The Wikipedia article on Betelgeuse seems at least good enough for our discussion here. It claims the photosphere (which is huge, large enough to be seen as a disk in large telescopes) has been shrinking fast for the last 15 years,: "The average speed at which the radius of the star is shrinking over the last 15 years is approximately 210–219 m/s (470–490 mph)."
I don't know the speed at which the shock wave will travel, but it won't be anywhere close to the speed of light, and it won't arrive "a few years" after the explosion. Space is full of old shocks ... they cause significant effects (local compression of gas that triggers formation of new stars, etc) but they are not world enders at this range. We're in a gas-poor region and the shock will weaken here as a result.
Taking Tom's data a little further, from the Wikipedia article http://en.wikipedia.org/wiki/Betelgeuse
There are several things that could be done with these numbers, but the first thing is to note that if the observations are of the final collapse to supernova, and considering the distance of 640 light years, then the second and third answer say that the supernova has already happened, some 485 to 540 years ago. The above three calculations are based on a constant average shrink rate but the shrink rate is accelerating, so the time remaining before observation of first radiation from the supernova is smaller than the calculated result. Further, the calculations assume collapse to Zero diameter before the supernova occurs. That is unrealistic but I can't guess what the final smallest diameter will be at supernova ignition. Both of these conditions portend ignition sooner, rather than later than the calculated values.
And I guess that if we assume that the observations are correct and the average shrink rate over 15 years really was 480 mph, and Betelgeuse really has shrunk 15 % over those same 15 years, then assuming some math model of the collapse rate, one could fit both numbers to calculate an earlier time when the radius will reach Zero. Then an estimate of the smallest final radius and one could use the math model to predict when supernova ignition occurred, hence when first radiation could be expected. Of course I guess that Charles Townes and the experts at UC Berkeley have already made some calculations along these lines.
This is fun, I hope some of you will play this game? Perhaps an astrophysicist?
And would it be feasible to send a robot probe toward Betelgeuse to act as a sort of "Early Warning" system?
These numbers are not terribly consistent. Using a linear projection, I calculated the time at which the radius will reach zero. Shrinking at 480 MPH gives 58,400 years. Shrinking 0.5 AU in 15 years gives 165 years, and shrinking 15 % in 15 years gives 100 years from 1993, or 85 more years. Feel free to check my arithmetic.the star has shrunk 15% since 1993 with an increasing rate. The average speed at which the radius of the star is shrinking over the last 15 years is approximately 210–219 m/s (470–490 mph).[24]
According to the university, Betelgeuse's radius is about 5.5 A.U.s, and the star's radius has shrunk by a distance equal to half an astronomical unit, ...
There are several things that could be done with these numbers, but the first thing is to note that if the observations are of the final collapse to supernova, and considering the distance of 640 light years, then the second and third answer say that the supernova has already happened, some 485 to 540 years ago. The above three calculations are based on a constant average shrink rate but the shrink rate is accelerating, so the time remaining before observation of first radiation from the supernova is smaller than the calculated result. Further, the calculations assume collapse to Zero diameter before the supernova occurs. That is unrealistic but I can't guess what the final smallest diameter will be at supernova ignition. Both of these conditions portend ignition sooner, rather than later than the calculated values.
And I guess that if we assume that the observations are correct and the average shrink rate over 15 years really was 480 mph, and Betelgeuse really has shrunk 15 % over those same 15 years, then assuming some math model of the collapse rate, one could fit both numbers to calculate an earlier time when the radius will reach Zero. Then an estimate of the smallest final radius and one could use the math model to predict when supernova ignition occurred, hence when first radiation could be expected. Of course I guess that Charles Townes and the experts at UC Berkeley have already made some calculations along these lines.
This is fun, I hope some of you will play this game? Perhaps an astrophysicist?
And would it be feasible to send a robot probe toward Betelgeuse to act as a sort of "Early Warning" system?
Aero
The probe could give early warning of an incoming shock wave, but not of electromagnetic radiation. The warning would travel at the same speed as the radiation.
I don't think there would be much value in launching a probe before we saw the supernova.
On the other hand, a probe set up to do that would answer all sorts of marvelous questions about the interstellar environment, the sort of things we're getting out of the Voyagers at present.
I don't think there would be much value in launching a probe before we saw the supernova.
On the other hand, a probe set up to do that would answer all sorts of marvelous questions about the interstellar environment, the sort of things we're getting out of the Voyagers at present.
Theoretically it could be done with entangled particles. That would appear to be FTL. In practice, you couldn't do it. Really.Tom Ligon wrote:The probe could give early warning of an incoming shock wave, but not of electromagnetic radiation. The warning would travel at the same speed as the radiation.
I don't think there would be much value in launching a probe before we saw the supernova.
On the other hand, a probe set up to do that would answer all sorts of marvelous questions about the interstellar environment, the sort of things we're getting out of the Voyagers at present.
What is the difference between ignorance and apathy? I don't know and I don't care.
pfrit,
Quantum entanglement communications? Better leave the science fiction to the pros!
I'm using such a communications device in a novel I'm working on, set in the not-too-distant future.
I don't think you could get it out far enough, fast enough, with chemical rockets. However, a Bussard DFP cis-Oort to interstellar design might make it useful, assuming an ansible communications device of some sort.
Quantum entanglement communications? Better leave the science fiction to the pros!
I'm using such a communications device in a novel I'm working on, set in the not-too-distant future.I don't think you could get it out far enough, fast enough, with chemical rockets. However, a Bussard DFP cis-Oort to interstellar design might make it useful, assuming an ansible communications device of some sort.
More News on Betelgeuse
The more I know, the less I know.
Actually, it is science, not fiction. Don't they have a quantum entanglement network in Europe now for the purpose of encryption? The problem is that the distance is in practice limited to a range of miles, not billions of miles. If you belong to the Copenhaagen interpretation group, it is impossible (not improbable) to build a network much longer than we have. If you belong to the Many Worlds interpretation group, than the network can be theoretically infiinite, but in practice the maximum practical size of a network would be not much longer than we have.Tom Ligon wrote:pfrit,
Quantum entanglement communications? Better leave the science fiction to the pros!
I don't think you could get it out far enough, fast enough, with chemical rockets. However, a Bussard DFP cis-Oort to interstellar design might make it useful, assuming an ansible communications device of some sort.
What is the difference between ignorance and apathy? I don't know and I don't care.
We've got two prospects for spectacular night sky. Betelgeuse and Eta Carinae. Eta Carinae's supernova will be much bigger than Betalgeuse's. however, it is more than 10 times further away as well. Given the inverse square law and the fact that Eta Carinae's hypernova should be at least 100 more powerful than Betelgeuse's supernova, Eta Carinae should make for a more impressive show in the sky when it blows. Any guesses on when it blows?
Correct me if I'm wrong, but I doubt either one would adversely affect us, assuming that we are not in the direct line of sight of the polar jets.
I like to see either one of these blow.
Correct me if I'm wrong, but I doubt either one would adversely affect us, assuming that we are not in the direct line of sight of the polar jets.
I like to see either one of these blow.
I would just as soon skip this one going off ...
http://www.space.com/scienceastronomy/0 ... rb-us.html
This is a binary containing a Wolf-Rayet stary, the pair known as WR104. Because the pinwheel effect the form is visible pretty much as a circle, they believe the polar jets would be pointed right at us.
Wolf-Rayets are extremely short-lived and die with extreme violence. This one is about 8000 LY out, but that's not far enough out for an on-axis GRB from a star of this type.
http://www.space.com/scienceastronomy/0 ... rb-us.html
This is a binary containing a Wolf-Rayet stary, the pair known as WR104. Because the pinwheel effect the form is visible pretty much as a circle, they believe the polar jets would be pointed right at us.
Wolf-Rayets are extremely short-lived and die with extreme violence. This one is about 8000 LY out, but that's not far enough out for an on-axis GRB from a star of this type.
I was looking for more information re: Betelgeuse. There are many articles but only the one source. Basically the same information that we have already posted here. I did find this interesting, related article though, National Geographic News
June 12, 2008.
http://news.nationalgeographic.com/news ... rnova.html
The ultraviolet flash that signals the explosion of a red supergiant star has been detected by astronomers for the first time.
"We have witnessed the violent death of a massive star in a galaxy almost a billion light-years away in unprecedented detail," said study team member Kevin Schawinski, an astrophysicist at the University of Oxford in the U.K.
June 12, 2008.
http://news.nationalgeographic.com/news ... rnova.html
The ultraviolet flash that signals the explosion of a red supergiant star has been detected by astronomers for the first time.
"We have witnessed the violent death of a massive star in a galaxy almost a billion light-years away in unprecedented detail," said study team member Kevin Schawinski, an astrophysicist at the University of Oxford in the U.K.
Aero
The scientist in the article say global warming is a bigger danger. So I guess there is hardly anything to worry about.Tom Ligon wrote:I would just as soon skip this one going off ...
http://www.space.com/scienceastronomy/0 ... rb-us.html
This is a binary containing a Wolf-Rayet stary, the pair known as WR104. Because the pinwheel effect the form is visible pretty much as a circle, they believe the polar jets would be pointed right at us.
Wolf-Rayets are extremely short-lived and die with extreme violence. This one is about 8000 LY out, but that's not far enough out for an on-axis GRB from a star of this type.
Engineering is the art of making what you want from what you can get at a profit.