Arniepie
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Betelgeuse Star To Become Supernova Soon

Thu Jun 11, 2009 10:24 am

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]
 
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vivekman2006
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RE: Betelgeuse Star To Become Supernova Soon

Thu Jun 11, 2009 10:44 am

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
 
prebennorholm
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RE: Betelgeuse Star To Become Supernova Soon

Sat Jun 13, 2009 1:36 am

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.
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nomadd22
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RE: Betelgeuse Star To Become Supernova Soon

Sat Jun 13, 2009 2:09 am



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.
Anon
 
britjap
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RE: Betelgeuse Star To Become Supernova Soon

Sat Jun 13, 2009 5:57 am



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
 
speedygonzales
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RE: Betelgeuse Star To Become Supernova Soon

Sat Jun 13, 2009 9:33 am

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
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kc135topboom
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RE: Betelgeuse Star To Become Supernova Soon

Sun Jun 14, 2009 4:53 pm



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.
 
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Tugger
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RE: Betelgeuse Star To Become Supernova Soon

Sun Jun 14, 2009 5:32 pm



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
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nomadd22
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RE: Betelgeuse Star To Become Supernova Soon

Mon Jun 15, 2009 11:38 am



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.
Anon
 
prebennorholm
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RE: Betelgeuse Star To Become Supernova Soon

Tue Jun 16, 2009 1:36 am



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
 
Blackbird
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RE: Betelgeuse Star To Become Supernova Soon

Tue Jun 16, 2009 7:36 pm

How much radiation will we end up getting hit with?
 
Oroka
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RE: Betelgeuse Star To Become Supernova Soon

Wed Jun 17, 2009 2:09 am



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.
 
Blackbird
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RE: Betelgeuse Star To Become Supernova Soon

Wed Jun 17, 2009 2:15 am

How long will the supernova last? They last years you know...
 
osiris30
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RE: Betelgeuse Star To Become Supernova Soon

Wed Jun 17, 2009 3:12 am

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?
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nomadd22
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RE: Betelgeuse Star To Become Supernova Soon

Wed Jun 17, 2009 12:01 pm



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.
Anon
 
Arniepie
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RE: Betelgeuse Star To Become Supernova Soon

Wed Jun 17, 2009 12:25 pm


[edit post]
 
osiris30
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RE: Betelgeuse Star To Become Supernova Soon

Wed Jun 17, 2009 1:40 pm



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 :)
 
nomadd22
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RE: Betelgeuse Star To Become Supernova Soon

Wed Jun 17, 2009 4:10 pm



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.
Anon
 
Fly2HMO
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RE: Betelgeuse Star To Become Supernova Soon

Wed Jun 17, 2009 8:38 pm

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?
 
Springbok747
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RE: Betelgeuse Star To Become Supernova Soon

Wed Jun 17, 2009 9:03 pm



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
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EA772LR
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RE: Betelgeuse Star To Become Supernova Soon

Wed Jun 17, 2009 9:11 pm

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?
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Phoenix9
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RE: Betelgeuse Star To Become Supernova Soon

Wed Jun 17, 2009 9:15 pm



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.
 
Phoenix9
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RE: Betelgeuse Star To Become Supernova Soon

Wed Jun 17, 2009 9:28 pm



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
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EA772LR
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RE: Betelgeuse Star To Become Supernova Soon

Wed Jun 17, 2009 9:32 pm



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.
 
aircatalonia
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RE: Betelgeuse Star To Become Supernova Soon

Thu Jun 18, 2009 12:30 am

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.
 
Phoenix9
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RE: Betelgeuse Star To Become Supernova Soon

Thu Jun 18, 2009 12:37 am

Quoting AirCatalonia (Reply 24):
And the ultimate reminder that we are nothing, dust in the space wind

Just to put that into perspective:



and that is just our backyard!

[Edited 2009-06-17 17:48:33]
Life only makes sense when you look at it backwards.
 
EA772LR
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RE: Betelgeuse Star To Become Supernova Soon

Thu Jun 18, 2009 3:11 am



Quoting Phoenix9 (Reply 25):
Just to put that into perspective:



and that is just our backyard!

I was reading that some astrophysicist theorize that matter (stars, nebulae, galaxies, etc) that were created quickly after the supposed Big Bang out about 13.7+Billion light years is expanding faster than the speed of light. Therefore, we will never be able to observe those parts of the universe because it's moving away from us quicker than the light can get to us. That's a theory that boggles my mind. The sheer distances. The closest star, Alpha Centauri, is approx. 4 light years or ~24,000,000,000,000 miles away  Wow! Our galaxy is ~100,000 light years across, the closest galaxy, Andromeda is 2.5 million light years from us. And to think that the edge of the observable universe is ~13.7 billion light years out is almost unfathomable. It's safe to say, the only space travel we'll be doing will be confined to our Solar System, unless we figure out how to fold space and time.
We often judge others by their actions, but ourselves by our intentions.
 
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Tugger
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RE: Betelgeuse Star To Become Supernova Soon

Thu Jun 18, 2009 3:16 am



Quoting Phoenix9 (Reply 25):

Just to put that into perspective:



and that is just our backyard!

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
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Phoenix9
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RE: Betelgeuse Star To Become Supernova Soon

Thu Jun 18, 2009 3:20 am



Quoting EA772LR (Reply 26):
expanding faster than the speed of light

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' towards the speed of light but is not at or faster than speed of light. The distances in space do boggle the mind and we can not really comprehend such distances because of the lack of a frame of reference.
Life only makes sense when you look at it backwards.
 
Phoenix9
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RE: Betelgeuse Star To Become Supernova Soon

Thu Jun 18, 2009 3:26 am



Quoting Tugger (Reply 27):
I don't see anything in your post. Am I missing something or is it supposed to be representing the vast nothingness of space?

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_you_are_here_small.jpg
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EA772LR
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RE: Betelgeuse Star To Become Supernova Soon

Thu Jun 18, 2009 3:39 am

Quoting Phoenix9 (Reply 28):
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' towards the speed of light but is not at or faster than speed of light.

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 energy is required to accelerate to the speed of light, therefore we would need and infinite source of energy. So for now, the speed of light is the speed limit of our universe. What the astrophysicist and theoretical physicist were getting at, is the matter produced at the instant the Big Bang exploded (all theory for now) that matter was ejected faster than the speed of light. Which I agree with you, still doesn't really make sense. I wish I was more educated on the subject so I could elaborate for you.

Quoting Phoenix9 (Reply 28):
The distances in space do boggle the mind and we can not really comprehend such distances because of the lack of a frame of reference.

Funny you mention that, as I was just talking with my Dad who's a huge astronomy buff. We were talking about the distances and how the human mind cannot grasp such distances because we have nothing on Earth to come close to understanding those distances. Just for fun I figured out how far the farthest quasar is from us...~12 Billion light years or simply written out - ~70,800,000,000,000,000,000,000 miles      

[Edited 2009-06-17 20:40:59]

[Edited 2009-06-17 20:44:31]
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DocLightning
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RE: Betelgeuse Star To Become Supernova Soon

Thu Jun 18, 2009 3:07 pm



Quoting EA772LR (Reply 30):
~12 Billion light years or simply written out - ~70,800,000,000,000,000,000,000 miles

Now, imagine flying all that distance on FR.  Wink
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EA772LR
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RE: Betelgeuse Star To Become Supernova Soon

Thu Jun 18, 2009 3:13 pm



Quoting DocLightning (Reply 31):
Now, imagine flying all that distance on FR. Wink

 rotfl  Oh geezus! Beam me up Scotty  yes 
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Tugger
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RE: Betelgeuse Star To Become Supernova Soon

Thu Jun 18, 2009 6:29 pm



Quoting EA772LR (Reply 30):
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 energy is required to accelerate to the speed of light, therefore we would need and infinite source of energy. So for now, the speed of light is the speed limit of our universe. What the astrophysicist and theoretical physicist were getting at, is the matter produced at the instant the Big Bang exploded (all theory for now) that matter was ejected faster than the speed of light. Which I agree with you, still doesn't really make sense. I wish I was more educated on the subject so I could elaborate for you.

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 separation speed that is greater than the speed of light.

To explain simply: Star "X" is ejected during the Big Bang at a speed of .51 the speed of light and Star "Y" is ejected in the exact opposite direction of "X" at the same speed, .51 the speed of light. Neither star shall ever see the light of the other.


Tugg
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EA772LR
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RE: Betelgeuse Star To Become Supernova Soon

Thu Jun 18, 2009 6:42 pm



Quoting Tugger (Reply 33):
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 separation speed that is greater than the speed of light.

To explain simply: Star "X" is ejected during the Big Bang at a speed of .51 the speed of light and Star "Y" is ejected in the exact opposite direction of "X" at the same speed, .51 the speed of light. Neither star shall ever see the light of the other.


Yes thank you Tugger.  checkmark  That is what I want to say, but couldn't formulate my words to explain.
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Phoenix9
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RE: Betelgeuse Star To Become Supernova Soon

Thu Jun 18, 2009 7:08 pm



Quoting Tugger (Reply 33):

To explain simply: Star "X" is ejected during the Big Bang at a speed of .51 the speed of light and Star "Y" is ejected in the exact opposite direction of "X" at the same speed, .51 the speed of light. Neither star shall ever see the light of the other.

Ah...we're talking about relative speeds...sorry I misunderstood. I was talking about considering one as a stationary point and then 'observing' from a stationary point but of course we can't take that into consideration since in space everything is relative. I stand corrected.
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NoWorries
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RE: Betelgeuse Star To Become Supernova Soon

Fri Jun 19, 2009 1:08 am



Quoting Tugger (Reply 33):
To explain simply: Star "X" is ejected during the Big Bang at a speed of .51 the speed of light and Star "Y" is ejected in the exact opposite direction of "X" at the same speed, .51 the speed of light. Neither star shall ever see the light of the other.

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 to one another and c is the speed of light. So even if two objects are moving away from each other at 99% of the speed of light, they will still appear to be moving less than the speed of light relative to one another. Under special relativity the speed of light is the same in all frames of refernce.

The reason that the light of one star might not ever reach the light of another is that the universe appears to be expanding at an ever increasing rate. If two stars were separated by sufficient distance after the big band, their light will never catch up to each other.
 
prebennorholm
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RE: Betelgeuse Star To Become Supernova Soon

Fri Jun 19, 2009 1:33 am

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 looks nicer, doesn't it?
Always keep your number of landings equal to your number of take-offs
 
TheCol
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RE: Betelgeuse Star To Become Supernova Soon

Fri Jun 19, 2009 2:21 am



Quoting FLY2HMO (Reply 18):
Wasn't there a supernova that occurred rather recently in the 1800's?

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.

http://messier.obspm.fr/more/m001_sn.html
http://en.wikipedia.org/wiki/History...upernova_observation#Early_history
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