http://news.yahoo.com/s/space/20090609/sc_space/populargiantstarshrinksmysteriously
A massive red star in the constellation Orion has shrunk in the past 15 years and astronomers don't know why.
Called Betelgeuse, the star is considered a red supergiant. Such massive stars are nearing the ends of their lives and can swell to 100 times their original size before exploding as supernovae, or possibly just collapsing to form black holes without violent explosions (as one study suggested).
Betelgeuse, one of the top 10 brightest stars in our sky, is a popular target among backyard skywatchers and was the first star ever to have its size measured, and even today is one of only a handful of stars that appears through the Hubble Space Telescope as a disk rather than a point of light. It was the first star (besides our sun) to have its surface photographed (by Hubble).
The new finding, presented today at a meeting of the American Astronomical Society in Pasadena, Calif., was based on data collected by UC Berkeley's Infrared Spatial Interferometer (ISI) on the top of Mt. Wilson in Southern California.
In 1993, measurements put Betelgeuse's radius at about 5.5 astronomical units (AU), where one AU equals the average Earth-sun distance of 93 million miles, or about 150 million km. Since then it has shrunk in size by 15 percent. That means the star's radius has contracted by a distance equal to the orbit of Venus.

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http://www.foxnews.com/story/0,2933,525695,00.html

I'm looking forward to seeing this beast explode. The supernova in 1054 AD created the Crab Nebula. According to ancient astronomers, it was bright enough to see in the daytime. The Crab Nebula is over 10x farther away than Betelgeuse. With that being said, if Betelgeuse explodes, it'll be as bright as the full moon. That'll be a hell of a light show.

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You will be assimilated...bunghole!

More from Foxnews:

http://www.foxnews.com/story/0,2933,525695,00.html

I'm looking forward to seeing this beast explode. The supernova in 1054 AD created the Crab Nebula. According to ancient astronomers, it was bright enough to see in the daytime. The Crab Nebula is over 10x farther away than Betelgeuse. With that being said, if Betelgeuse explodes, it'll be as bright as the full moon. That'll be a hell of a light show.

Not just light. X-Rays and Gamma rays too. And a huge pile of neutrinos. And some nice big gravity waves too.

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Not just light. X-Rays and Gamma rays too. And a huge pile of neutrinos. And some nice big gravity waves too.

Well of course that's true, just the average person looking up at a huge "second star" in the sky at high noon won't notice the x-rays and gamma rays. :)

Now that you mention it though, you think Einstein@home will detect the gravity waves given off by the explosion? Something of that magnitude has to give off some pretty sizable ripples in spacetime.

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You will be assimilated...bunghole!

Not just light. X-Rays and Gamma rays too. And a huge pile of neutrinos. And some nice big gravity waves too.

Well of course that's true, just the average person looking up at a huge "second star" in the sky at high noon won't notice the x-rays and gamma rays. :)

Now that you mention it though, you think Einstein@home will detect the gravity waves given off by the explosion? Something of that magnitude has to give off some pretty sizable ripples in spacetime.

They might notice the radiation sickness however.

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They might notice the radiation sickness however.

heh, not at this distance. :) It'd only be dangerous if it were within 100ly or so.

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You will be assimilated...bunghole!

If it is shrinking, does that mean that enough of its mass has reached escape velocity from the gravity of the star to cause the gravity to then pull the star back in on itself? Or maybe it has burned up enough of its fuel to cause this process. What explanation would fit this phenomenon the best?
m

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It would be awesome to see it go, but, the problem is that we don’t very much about these things. We don’t know how long it takes a star to pass through the red giant stage or how long the star has been a red giant. Does the stage last 20,000 years or 2,000,000? Is it just entering the stage, in the middle or about to leave it? The stinking could just be part of a normal cycle of pulsations that could go on for tens of thousands of years.

Sorry to be a buzz kill. :-(

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It would be awesome to see it go, but, the problem is that we don’t very much about these things. We don’t know how long it takes a star to pass through the red giant stage or how long the star has been a red giant. Does the stage last 20,000 years or 2,000,000? Is it just entering the stage, in the middle or about to leave it? The stinking could just be part of a normal cycle of pulsations that could go on for tens of thousands of years.

Sorry to be a buzz kill. :-(

Exactly, which is why everybody is keeping a close eye on it. For all we know, it has already exploded and we won't see it for years. I guarantee though, when the light from the explosion reaches us, we'll know it. :)

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You will be assimilated...bunghole!

I was reading somewhere that when this baby pops it will be well visible during daytime, should be a very exotic sight. On the subject of stellar explosions...

Internal visualizations of an Exploding Star

Balveda

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I was reading somewhere that when this baby pops it will be well visible during daytime, should be a very exotic sight. On the subject of stellar explosions...

Internal visualizations of an Exploding Star

Balveda

SN 1054 (a supernova taking places in 1054 AD) was about 6,500 light years away and visible during the day for nearly a month. Betelgeuse is 10 times closer (640 light years), so it'll probably appear to be a second sun in the daytime sky, and it'll be brighter than the full moon at night.

http://en.wikipedia.org/wiki/Betelgeuse#Fate

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You will be assimilated...bunghole!

ok the material from the 1054 super nova is traveling at around 1/2 the speed of light or less. so in a few thousand years we'll be getting matter spat out by that explosion passing through our solar system. if betelguise goes nova anytime soon, if it already hasn't(we are seeing light from over 600 years ago from the star) then we will have ejecta heading our way even sooner

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In a rich man's house there is no place to spit but his face.
Diogenes Of Sinope

ok the material from the 1054 super nova is traveling at around 1/2 the speed of light or less. so in a few thousand years we'll be getting matter spat out by that explosion passing through our solar system. if betelguise goes nova anytime soon, if it already hasn't(we are seeing light from over 600 years ago from the star) then we will have ejecta heading our way even sooner

Make for some pretty sunsets. :) Hey you know how in Star Trek / Star Wars many worlds have huge nebulae in the night sky? Might be Earth in a few hundred years. :)

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You will be assimilated...bunghole!

If its physically big enough and it as it blows and also creates a back pressure wave, it may turn into a black hole...

That would be trouble for the neighbourhood.. including earth.

If its physically big enough and it as it blows and also creates a back pressure wave, it may turn into a black hole...

That would be trouble for the neighbourhood.. including earth.

It's nearly 600ly away...a black hole there wouldn't affect us one bit.

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You will be assimilated...bunghole!

If its physically big enough and it as it blows and also creates a back pressure wave, it may turn into a black hole...

That would be trouble for the neighbourhood.. including earth.

It's nearly 600ly away...a black hole there wouldn't affect us one bit.

I read It is 640ly, In any case I agree It isn't near enough to do diddly squat to US, But We'll get a bang out of watchin It go BOOOM! :)

Wikipedia gives two figures...430ly and 570ly

http://en.wikipedia.org/wiki/Betelgeuse#Fate

NASA gives 640ly, and this appears to be an explanation as to the different sizes:

http://berkeley.edu/news/media/releases/2009/06/09_betelim.shtml

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You will be assimilated...bunghole!

The Aug 5th, 2009, APOD shows a previously unseen plume emerging from the big star.

http://apod.nasa.gov/apod/ap090805.html

Is it possible that Betelgeuse has a previously unseen/undetected close neighbor? Or took a near-miss shot from a passing object that is still pulling material away from it?

Martin
[edited to add img url]

If its physically big enough and it as it blows and also creates a back pressure wave, it may turn into a black hole...

That would be trouble for the neighbourhood.. including earth.

It's nearly 600ly away...a black hole there wouldn't affect us one bit.

folks
500-600Ly is inside the neighbourhood. The gravitational effect of a blackhole (if one existed within this range) would make a difference... it may be small but it would be constant, over time. The initial distortion ripples would easily be measured here. I most certainly wont be alive to see the event, but a supernova would be preferable to a black hole. The nova happens once and is gone, a black hole continually consumes matter and distorts space like a sink without the plug in place...

Remember we are in a galaxy that is slowly being consumed by a large black hole in the middle. We are sliding down a long spiral causeway.

Conjecture: Eventually it will either consume the lot or it will reach a "full" level and perhaps it may be possible that it will explode violently showering what is left with intense radiation at multiple frequencies.

Pure conjecture on my part but perhaps this is what creates ring galaxies, the middle is eaten away and perhaps when the blackhole finally explodes it pushes the remains outwards and onwards. It would be interesting to see what the x-ray and gamma ray images of these ring galaxies is like.

Remember we are in a galaxy that is slowly being consumed by a large black hole in the middle. We are sliding down a long spiral causeway.

Not really...this far away we're in no danger from being swallowed by the black hole in the center of the galaxy. Most stars in most galaxies are in stable orbits and will never even come close to the center.

A normal black hole is even less dangerous. The only way a black hole 600ly away could affect us is if it emitted jets of matter and energy directly towards us. The gravitational ripples from it's formation will be temporary.

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You will be assimilated...bunghole!

Are you folks sure about the lack of effect on Earth? I remember reading somewhere that the radiation from a Supernova "near" us could make the Earth uninhabitable...so how near is "near"?
Remember, a SN can be as bright as a whole Galaxy - the equivalent of billions of stars....

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