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Betelgeuse Star To Become Supernova Soon  
User currently offlineArniepie From Belgium, joined Aug 2005, 1265 posts, RR: 1
Posted (5 years 3 months 1 week 3 days 23 hours ago) and read 5921 times:

At 600 lightyears away from earth , the supergiant star Betelgeuze ( left top star in ORION constellation) is on the brink of becoming a supernova and will be the second brightest object on the sky, after our own sun.
Shrinking about 15% in 15 years time it might already have exploded by now, whe're up for a great show, hopefully I'll see it in my lifetime.

http://blogs.discovery.com/space_dis...ing-supernova-or-supernothing.html


[edit post]
38 replies: All unread, showing first 25:
 
User currently offlineVivekman2006 From India, joined May 2006, 540 posts, RR: 3
Reply 1, posted (5 years 3 months 1 week 3 days 23 hours ago) and read 5910 times:

The article says:

Quote:
Yes, it's totally possible Betelgeuse could explode, but the chances of this happening in this 600 year window is highly unlikely, regardless how fast it seems to be shrinking.

So is there a chance of we getting to see any visual effects in our life time?

Also, how bright does a supernova appear? If you are saying that it would be the second brightest object in the sky after the sun, will it be brighter than the moon? By how much?

- Vivek


User currently offlinePrebennorholm From Denmark, joined Mar 2000, 6451 posts, RR: 54
Reply 2, posted (5 years 3 months 1 week 2 days 8 hours ago) and read 5598 times:

Betelguese has always been somewhat unstable. It was first described as a highly variable star by Sir John Herchel back in 1836. It may have exploded as a type II supernova 599 years ago, or it may happen in a million years time. We cannot know.

When it happens it will for a month or two give a visible light comparable to the full Moon.

But for many years Betelguese has varied its size and luminosity. Diameter is believed to vary between roughly 180 million and 280 million miles. Its mass is some 20 times the Sun, but volume is several hundred million times the Sun since diameter is comparable to the orbit of Mars. Luminosity has during the last couple of hundred years varied between mag 0.2 and 1.2 - or roughly by a factor 2.5.

For sure it has been shrinking during the last couple of decades. But it has been shrinking and expanding many thousand times since it became a red gigant star. And sure a type II supernova begins with the star imploding. But the chance for us to see that is very small.

The axis of rotation of Betelguese has recently been found. Since it is far from pointing our way, then there should be no risk of a serious gamma ray burst which otherwise might threaten our ecosystem.



Always keep your number of landings equal to your number of take-offs, Preben Norholm
User currently offlineNomadd22 From United States of America, joined Feb 2008, 1866 posts, RR: 0
Reply 3, posted (5 years 3 months 1 week 2 days 7 hours ago) and read 5591 times:



Quoting Prebennorholm (Reply 2):
but volume is several hundred million times the Sun since diameter is comparable to the orbit of Mars

Diameter of 180 million miles would give it about 8 million times the sun's volume.



Andy Goetsch
User currently offlineBritJap From Japan, joined Aug 2006, 280 posts, RR: 2
Reply 4, posted (5 years 3 months 1 week 2 days 3 hours ago) and read 5548 times:



Quoting Nomadd22 (Reply 3):
Quoting Prebennorholm (Reply 2):
but volume is several hundred million times the Sun since diameter is comparable to the orbit of Mars

Diameter of 180 million miles would give it about 8 million times the sun's volume.

Don't ask me how accurate it is but it does give a nice impression.....
(Betelguese appears towards the end!!)

http://www.youtube.com/watch?v=DU2i9diMfxU


User currently offlineSpeedyGonzales From Norway, joined Sep 2007, 732 posts, RR: 0
Reply 5, posted (5 years 3 months 1 week 2 days ago) and read 5514 times:

The outer envelopes of giant stars can be described as a "hot vacuum", as it has extremely low density. Using 20 M☉ as mass and 950 R☉ as radius (http://en.wikipedia.org/wiki/Betelguese) the average density of Betelguese is only ~33mg/m^3, or about 36000 times lower than air at sea level (1,2 kg/m^3). The outer parts will be significantly less dense than the average.

Excenllent comparison of sizes:
http://en.wikipedia.org/wiki/File:Star-sizes.jpg



Las Malvinas son Argentinas
User currently offlineKC135TopBoom From United States of America, joined Jan 2005, 12146 posts, RR: 51
Reply 6, posted (5 years 3 months 1 week 16 hours ago) and read 5370 times:



Quoting Prebennorholm (Reply 2):
The axis of rotation of Betelguese has recently been found. Since it is far from pointing our way, then there should be no risk of a serious gamma ray burst which otherwise might threaten our ecosystem.

Are we sure about that? Are we sure a gamma ray burst will only shoot out along the axis? But, you are right, a gamma ray burst would be a very bad thing for Earth.


User currently offlineTugger From United States of America, joined Apr 2006, 5604 posts, RR: 8
Reply 7, posted (5 years 3 months 1 week 16 hours ago) and read 5358 times:



Quoting BritJap (Reply 4):
Don't ask me how accurate it is but it does give a nice impression.....



Quoting SpeedyGonzales (Reply 5):
Excenllent comparison of sizes:

Anything like this that shows relative sizes as compared to the Solar system?
Thanks,

Tugg



I don’t know that I am unafraid to be myself, but it is hard to be somebody else. -W. Shatner
User currently offlineNomadd22 From United States of America, joined Feb 2008, 1866 posts, RR: 0
Reply 8, posted (5 years 3 months 6 days 22 hours ago) and read 5271 times:



Quoting SpeedyGonzales (Reply 5):
The outer envelopes of giant stars can be described as a "hot vacuum", as it has extremely low density. Using 20 M☉ as mass and 950 R☉ as radius (http://en.wikipedia.org/wiki/Betelguese) the average density of Betelguese is only ~33mg/m^3, or about 36000 times lower than air at sea level (1,2 kg/m^3). The outer parts will be significantly less dense than the average.

That's why I doubt if the giants really look anything like the artists concepts. As diffuse as the outer parts are there's no way they could have the nice smooth, well defined surface as a smaller star. They probably look more like big fuzzy gas clouds.

Quoting KC135TopBoom (Reply 6):
Are we sure about that? Are we sure a gamma ray burst will only shoot out along the axis? But, you are right, a gamma ray burst would be a very bad thing for Earth.

I think the idea is that that the gamma ray burst comes with the final stage of collapse when the neutron star or black hole is formed and the core's spin accelerates so fast it creates a ludicrous strength magnetic field that funnels the burst along the poles.
The jet is pretty narrow, which is why out of hundreds of millions of collapses in the observable universe every year, we only detect bursts from a few hundred.



Andy Goetsch
User currently offlinePrebennorholm From Denmark, joined Mar 2000, 6451 posts, RR: 54
Reply 9, posted (5 years 3 months 6 days 8 hours ago) and read 5156 times:



Quoting KC135TopBoom (Reply 6):
Are we sure a gamma ray burst will only shoot out along the axis? But, you are right, a gamma ray burst would be a very bad thing for Earth.

That's what the scientists tell us. They also tell us that the axis point 20 degrees aways from Earth, so the gamma ray burst will miss Earth by almost a couple of hundred comfortable lightyears.

But there is nothing unusual in red gigant stars like Betelguese ballooning in and out. Spectral analizes of many stars has told us that for a long time. The only unusual thing is that with Betelguese being so close to us it has now been proven visually.

Betelguese may easily last another million years or more. But compared to the Sun it is of course extremely shortlived. It has spent less than eight million years as a main sequence star while the Sun will outdo that by a factor 1,000 to 1,500.

It may have suffered a type II supernova 600 years ago, we cannot know. But the chance that present generations of homo sapient on planet Earth will live to see that is probably like one in 10,000 to one in 100,000. I wouldn't bet any money on that.



Always keep your number of landings equal to your number of take-offs, Preben Norholm
User currently offlineBlackbird From , joined Dec 1969, posts, RR:
Reply 10, posted (5 years 3 months 5 days 14 hours ago) and read 5059 times:

How much radiation will we end up getting hit with?

User currently offlineOroka From Canada, joined Dec 2006, 913 posts, RR: 0
Reply 11, posted (5 years 3 months 5 days 7 hours ago) and read 5007 times:



Quoting Blackbird (Reply 10):
How much radiation will we end up getting hit with?

Only the radiation of the light we will see from the fireworks.


User currently offlineBlackbird From , joined Dec 1969, posts, RR:
Reply 12, posted (5 years 3 months 5 days 7 hours ago) and read 5007 times:

How long will the supernova last? They last years you know...

User currently offlineOsiris30 From Barbados, joined Sep 2006, 3192 posts, RR: 25
Reply 13, posted (5 years 3 months 5 days 6 hours ago) and read 4995 times:

Just a question, but if the star was undergoing gravitational collapse (i.e. starting to go supernova), wouldn't the rate of contraction be exponential in nature?


I don't care what you think of my opinion. It's my opinion, so have a nice day :)
User currently offlineNomadd22 From United States of America, joined Feb 2008, 1866 posts, RR: 0
Reply 14, posted (5 years 3 months 4 days 21 hours ago) and read 4928 times:



Quoting Osiris30 (Reply 13):
Just a question, but if the star was undergoing gravitational collapse (i.e. starting to go supernova), wouldn't the rate of contraction be exponential in nature?

Yep. The outer layers start falling inward and the closer to the core they get the stronger the gravitational field, so the acceleration accelerates. The rate as measured from the outside slows down when it approaches lightspeed, but the mass of the particles increase, so it comes out to the same thing momentum wise.
This type supernova happens when the momentum plus the gravity is enough to overcome the electron pressure and push them into the nuclei changing protons to neutrons and creating a neutron star. If there's enough mass to overcome the bounce you get from that and overcome the forces that keep neutrons distinct, they collapse and you get a black hole.
Much more complicated than that, of course. The interactions in that last few milliseconds of collapse are so complicated the best models and supercomputers are just beginning to get a handle on them.



Andy Goetsch
User currently offlineArniepie From Belgium, joined Aug 2005, 1265 posts, RR: 1
Reply 15, posted (5 years 3 months 4 days 21 hours ago) and read 4920 times:





[edit post]
User currently offlineOsiris30 From Barbados, joined Sep 2006, 3192 posts, RR: 25
Reply 16, posted (5 years 3 months 4 days 20 hours ago) and read 4901 times:



Quoting Nomadd22 (Reply 14):

Yep. The outer layers start falling inward and the closer to the core they get the stronger the gravitational field, so the acceleration accelerates. The rate as measured from the outside slows down when it approaches lightspeed, but the mass of the particles increase, so it comes out to the same thing momentum wise.

Thank you, nice to see some thing in physics still behave as logical deduction would have you think  Wink

So the question is, does the shrinking of this star conform to that pattern or not. Seems to me like it would be fairly straight forward to have some inkling if it's just a contraction or if it's actually the start of a supernova. (**straight forward in this sense means, if you can measure that it has shrunk, you can measure how fast it is shrinking, and with the two presto.. I'm not trying to imply measuring something 600 light years away is trivial).



I don't care what you think of my opinion. It's my opinion, so have a nice day :)
User currently offlineNomadd22 From United States of America, joined Feb 2008, 1866 posts, RR: 0
Reply 17, posted (5 years 3 months 4 days 17 hours ago) and read 4872 times:



Quoting Osiris30 (Reply 16):
So the question is, does the shrinking of this star conform to that pattern or not. Seems to me like it would be fairly straight forward to have some inkling if it's just a contraction or if it's actually the start of a supernova. (**straight forward in this sense means, if you can measure that it has shrunk, you can measure how fast it is shrinking, and with the two presto.. I'm not trying to imply measuring something 600 light years away is trivial).

They can tell when the star is in it's final stages by detecting the spectrum you'd see from iron making reactions, but predicting the normal cycles of expansion and contraction of stars is still a baby science.
The normal expanding and contractiong caused by varying nuclear activity goes on over years or thousands of years. Our sun does it a little bit. The collapse leading to the supernova happens almost instantly. The core hasn't been active for a long time and when the heavy element fusion in the farther out layers goes below a certain point, it stops completely in a few seconds leading to the collapse. The outer most layers can't fall in that fast, being several light minutes from the core, so you wouldn't actually see the collapse from a disance like in a Star Trek episode.
In a Betelgeuse type supernova, it's the jam up of the material trying to reach the core that causes the explosion. The rebound is intense enough to create all the heavier than iron elements that you can't make with steady state fusion.

Any radiation you can detect from the falling matter could have it's speed measured by doppler shift, but unless you can analyze it in five seconds or so, the star exploding would probably be a hint it's not a normal contraction.



Andy Goetsch
User currently offlineFLY2HMO From , joined Dec 1969, posts, RR:
Reply 18, posted (5 years 3 months 4 days 13 hours ago) and read 4821 times:

Man I would love to see a supernova. Doubt it will happen in my lifetime though.

Wasn't there a supernova that occurred rather recently in the 1800's?


User currently offlineSpringbok747 From Australia, joined Nov 2004, 4387 posts, RR: 10
Reply 19, posted (5 years 3 months 4 days 12 hours ago) and read 4805 times:



It would be cool to see one, though it looks like it won't be visible in our lifetime. On a related note..anyone know about the 'Pillars of Creation' in the Eagle Nebula? I'm talking about this one:

http://en.wikipedia.org/wiki/Pillars_of_Creation

Apparently it no longer exists as it has been toppled by a stellar blast some 6000 years ago, but it is still visible to us and will remain visible for another 1000 years as it is some 7000 light years away..so the aftermath of the blast will only be visible to us after a 1000 years. Interesting stuff.

http://www.space.com/scienceastronomy/070109_toppled_pillars.html



אני תומך בישראל
User currently offlineEA772LR From United States of America, joined Mar 2007, 2836 posts, RR: 10
Reply 20, posted (5 years 3 months 4 days 12 hours ago) and read 4794 times:

Some really great and informative posts!  thumbsup  I have to admit I am a total novice when it comes to astronomy, and pardon my ignorance, but what causes a star to collapse within itself?


We often judge others by their actions, but ourselves by our intentions.
User currently offlinePhoenix9 From Canada, joined Aug 2007, 2546 posts, RR: 8
Reply 21, posted (5 years 3 months 4 days 12 hours ago) and read 4791 times:



Quoting Springbok747 (Reply 19):
Apparently it no longer exists as it has been toppled by a stellar blast some 6000 years ago, but it is still visible to us and will remain visible for another 1000 years as it is some 7000 light years away..so the aftermath of the blast will only be visible to us after a 1000 years. Interesting stuff.

Amazing isn't it. Something that we say is a million light years away....was there million years ago....so basically in a sense, we are looking into past. So who knows what stage Betelgeuse is at this point!



Life only makes sense when you look at it backwards.
User currently offlinePhoenix9 From Canada, joined Aug 2007, 2546 posts, RR: 8
Reply 22, posted (5 years 3 months 4 days 12 hours ago) and read 4774 times:



Quoting EA772LR (Reply 20):
what causes a star to collapse within itself?

It happens towards the end of a large star's lifecycle when the fuel is burned off. The high gravity of a very large star causes the material to collapse towards the core...the core pushes back due to the neutron denisty. Things at this point basically go apesht and the star ends up exploding.

This would be a good place to start:

http://en.wikipedia.org/wiki/Supernova



Life only makes sense when you look at it backwards.
User currently offlineEA772LR From United States of America, joined Mar 2007, 2836 posts, RR: 10
Reply 23, posted (5 years 3 months 4 days 12 hours ago) and read 4768 times:



Quoting Phoenix9 (Reply 22):
It happens towards the end of a large star's lifecycle when the fuel is burned off. The high gravity of a very large star causes the material to collapse towards the core...the core pushes back due to the neutron denisty. Things at this point basically go apesht and the star ends up exploding.

This would be a good place to start:

Thank you  thumbsup 

Yeah as soon as I made my post, I realized I was staring at the largest encyclopedia in the world *cough* the internet, and was just being lazy! But thank you also for the link.



We often judge others by their actions, but ourselves by our intentions.
User currently offlineAirCatalonia From Spain, joined Nov 2007, 558 posts, RR: 0
Reply 24, posted (5 years 3 months 4 days 9 hours ago) and read 4717 times:

That would be awesome!

An impressive show, for sure. And the ultimate reminder that we are nothing, dust in the space wind, even in a time of internet and all sorts of technological advances.


25 Post contains images Phoenix9 : Just to put that into perspective: and that is just our backyard![Edited 2009-06-17 17:48:33]
26 EA772LR : I was reading that some astrophysicist theorize that matter (stars, nebulae, galaxies, etc) that were created quickly after the supposed Big Bang out
27 Tugger : I don't see anything in your post. Am I missing something or is it supposed to be representing the vast nothingness of space? Tugg
28 Phoenix9 : Something is fishy here though....nothing can move faster than speed of light (well at least as far as we know), the expansion rate 'approaches' towa
29 Post contains links Phoenix9 : There is a picture that should be showing. I can see it on my computer. You can check it out here: http://binarri.edu.au/moodle/file.ph.../2/milkyway
30 Post contains images EA772LR : Right. According to Einstein, and he's been right thus far, the closer we get to the speed of light, the more mass we begin to gain, therefore more e
31 DocLightning : Now, imagine flying all that distance on FR.
32 EA772LR : Oh geezus! Beam me up Scotty
33 Tugger : If I understand what the astrophysicist and theoretical physicist were getting at, it is the COMBINED speeds of the two objects that bring us to a se
34 EA772LR : Yes thank you Tugger. That is what I want to say, but couldn't formulate my words to explain.
35 Phoenix9 : Ah...we're talking about relative speeds...sorry I misunderstood. I was talking about considering one as a stationary point and then 'observing' from
36 NoWorries : Under special relativity, the rule for combining speeds is (a + b) / (1 + (a/c)( b/c)) where a and b are the two objects moving along a line relative
37 Prebennorholm : My old car just passed 300,000 miles today (480,000 km). When I put it on Ebay, then I think that I will write "One owner and 1.6 light seconds". It l
38 Post contains links TheCol : There have been a number of supernovas that have been documented by ancient China and other cultures. The most significant event was in 1054 A.D. htt
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