Were Doomed.... again!

#2
Well the blast wave can't outrun the speed of light, and if it's 3,000 light years away I don't think I'll getting too worried.
 
#4
JoeCivvie said:
Well the blast wave can't outrun the speed of light, and if it's 3,000 light years away I don't think I'll getting too worried.
There is hope!

At last, an end in sight for to the PC nonsense!
 
#6
JoeCivvie said:
Well the blast wave can't outrun the speed of light, and if it's 3,000 light years away I don't think I'll getting too worried.
True, but if we can see that it's gone bang, then the supernova must have happened 3000 years ago, and we are only seeing it now.

So it would all depend on how much slower the blast wave is than the speed of light. 'Flash to bang' sort of thing.
 
#7
Phooey said:
JoeCivvie said:
Well the blast wave can't outrun the speed of light, and if it's 3,000 light years away I don't think I'll getting too worried.
True, but if we can see that it's gone bang, then the supernova must have happened 3000 years ago, and we are only seeing it now.

So it would all depend on how much slower the blast wave is than the speed of light. 'Flash to bang' sort of thing.
I think by blast wave they actually mean the flash...... so 'tis more of a 'Flash - f*ck' :)
 
#8
Phooey said:
JoeCivvie said:
Well the blast wave can't outrun the speed of light, and if it's 3,000 light years away I don't think I'll getting too worried.
True, but if we can see that it's gone bang, then the supernova must have happened 3000 years ago, and we are only seeing it now.

So it would all depend on how much slower the blast wave is than the speed of light. 'Flash to bang' sort of thing.
Although unlikely given the time scales involved, it’s possible that the event has already taken place and we are about to find out about it in the form of a second Sun as the light reaches us, being visible during daylight for a few weeks or months. The only possibly significant effect could be the short lived disturbing of bird and animal behaviour as well as plant cycles while the “second Sun” persisted.

If there wasn’t anything in the way the matter shockwave could be just a little behind the “light sphere” and so arrive within a few years of the latter. However, at over 3k light years away the energy density per unit area would be negligible, at best, by the time the wave reached us. Interstellar dust close to the event would absorb almost all of the matter in any case, resulting in a growing nebula visible through a decent set of binoculars within a few years. What would reach us would be a slightly higher than usual high energy particle flux noticeable only through specialised equipment.

Again, given the vast time scales involved, it’s a non-story really, meant for interest, but with the usual media’s alarmist spin. I’d quite like it to happen in my lifetime. I missed the last close one; the Crab Nebula event in 1054:

http://en.wikipedia.org/wiki/Crab_nebula
 
#9
I'm trying to calculate the effect on the Earth, but I've come up with a problem. What's 20 billion billion billion megatons in SI units? It's bad enough not knowing if the billion is US (1,000,000,000) or UK (1,000,000,000,000), but when you get a unit repeated more than once, I get confused. I mean, is a trillion a thousand billion or a billion billion?

If someone can help, please hurry as we may not have much time...
 
#12
cometcatcher said:
Well ScouseD, let's just hope Betelgeuse went belly up oh, say... 630 years ago?
Then we've got another 10 years to wait. (it's Approx 640 light years away)
 
#13
...and what about the bang? If sound doesn't travel through a vacuum, will it be a silent explosion? Without a bang, there's be no blast, so a bit less to worry about.
 
#15
Phooey said:
cometcatcher said:
Well ScouseD, let's just hope Betelgeuse went belly up oh, say... 630 years ago?
Then we've got another 10 years to wait. (it's Approx 640 light years away)
I’ve been waiting for Betelgeuse to go supernova since I was a kid, and to be honest I’m getting a little impatient…

The event would certainly be spectacular, but again given the vast distances involved nothing to be overly concerned about. Taking a simple linear approach the energy and matter densities would follow the inverse square law on their way towards us, meaning that again the effects would be negligible, apart that is from a humongous light in the sky for quite a while. That would certainly mess up natural cycles, but there isn’t anything in the fossil record to show that these events, which must have happened in the past, resulted in any sort of catastrophe.
 
#16
Relax, guys. Everyone knows the world won't end until 2012. :wink:

Although it does look like the Fimbulwinter outside my window right now... 8O
 
#17
putteesinmyhands said:
I'm trying to calculate the effect on the Earth, but I've come up with a problem. What's 20 billion billion billion megatons in SI units? It's bad enough not knowing if the billion is US (1,000,000,000) or UK (1,000,000,000,000), but when you get a unit repeated more than once, I get confused. I mean, is a trillion a thousand billion or a billion billion?

If someone can help, please hurry as we may not have much time...
A billion has been internationally standardised since the 1960s as 1,000,000,000. So 20 billion, billion, billion megatons is 20,000,000,000 000,000,000, 000,000,000 000,000 tons, or 2 x 10^34 tons (although tons isn’t an SI unit).

Hope this helps :D
 
#18
ScouseD said:
Phooey said:
cometcatcher said:
Well ScouseD, let's just hope Betelgeuse went belly up oh, say... 630 years ago?
Then we've got another 10 years to wait. (it's Approx 640 light years away)
I’ve been waiting for Betelgeuse to go supernova since I was a kid, and to be honest I’m getting a little impatient…

The event would certainly be spectacular, but again given the vast distances involved nothing to be overly concerned about. Taking a simple linear approach the energy and matter densities would follow the inverse square law on their way towards us, meaning that again the effects would be negligible, apart that is from a humongous light in the sky for quite a while. That would certainly mess up natural cycles, but there isn’t anything in the fossil record to show that these events, which must have happened in the past, resulted in any sort of catastrophe.
Quite, but just think of the nebula....
 
#19
cometcatcher said:
Edit: Puttees, this is the kind of supernova expected in the Times article http://en.wikipedia.org/wiki/Type_Ia_supernova
The linked reference says that there'll be a shock wave but a linked page says that shock waves can only travel through a medium (not in space) or through an electromagnetic field. As light, magnetism and electricity are silent, can I take it that I don't need to secure loose crockery?
 
#20
ScouseD said:
putteesinmyhands said:
I'm trying to calculate the effect on the Earth, but I've come up with a problem. What's 20 billion billion billion megatons in SI units? It's bad enough not knowing if the billion is US (1,000,000,000) or UK (1,000,000,000,000), but when you get a unit repeated more than once, I get confused. I mean, is a trillion a thousand billion or a billion billion?

If someone can help, please hurry as we may not have much time...
A billion has been internationally standardised since the 1960s as 1,000,000,000. So 20 billion, billion, billion megatons is 20,000,000,000 000,000,000, 000,000,000 000,000 tons, or 2 x 10^34 tons (although tons isn’t an SI unit).

Hope this helps :D
Thanks. I'll get back in a minute.
 

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