|
|
|
|
pleco
SFN Addict
USA
2998 Posts |
 Posted - 09/13/2005 : 04:35:27
|
quote:
Astronomers say they have detected a 13-billion-year-old cosmic explosion at the very edge of the visible universe that could help them learn more about the earliest stars.
The brilliant blast, which is known as a gamma ray burst (GRB), was probably caused by the death of a massive star soon after the Big Bang.
However, it was glimpsed on September 4 by NASA's new Swift satellite and later by ground-based telescopes.
The explosion occurred soon after the first stars and galaxies formed, perhaps 500 million to 1 billion years after the Big Bang explosion that scientists believe gave birth to the cosmos.
The current scientific estimate for the age of the universe is 13.7 billion years.
http://www.abc.net.au/news/newsitems/200509/s1458880.htm
Okay, please help me out here. This explosion occured almost 13 billion years ago and the energy is just now getting to us? How is this possible? I don't recall reading anywhere that the expansion of the universe is at or beyond the speed of light.
So how can the Earth just now see this explosion that occured when the universe was much smaller? I would think that when the explosion happened, the light/energy from it would have already expanded to the borders of the universe (at that time) and that would be the end of it.
It is very early in the morning here, so maybe my synapses haven't got up to speed yet. Am I missing something very basic here?
|
by Filthy
The neo-con methane machine will soon be running at full fart. |
|
|
|
Subjectmatter
Skeptic Friend
173 Posts |
 Posted - 09/13/2005 : 06:58:22 [Permalink]
|
| I have always understood there not to be any borders of the universe. That if you move sufficiently far from any one point you will in the end come back to it. This being because a particle follows straight vector in all four dimensions, but due to the curvature of space time, one perceives it as being a curve in three. |
Sibling Atom Bomb of Couteous Debate |
 |
|
|
markie
Skeptic Friend
Canada
356 Posts |
Posted - 09/13/2005 : 20:31:09 [Permalink]
|
quote:
Originally posted by pleco
Okay, please help me out here. This explosion occured almost 13 billion years ago and the energy is just now getting to us? How is this possible? I don't recall reading anywhere that the expansion of the universe is at or beyond the speed of light.
So how can the Earth just now see this explosion that occured when the universe was much smaller? I would think that when the explosion happened, the light/energy from it would have already expanded to the borders of the universe (at that time) and that would be the end of it.
It is very early in the morning here, so maybe my synapses haven't got up to speed yet. Am I missing something very basic here?
I suppose this is why the 'inflation' model was invented. First, you have the big bang supposedly 13.7 +/-.3 bya. The energy of the bang fills the entire universe, fairly uniformly. (That is allegedly the cosmic microwave background radiation we experience today.) Then space itself decides to inflate incredibly fast, far outpacing the speed of light for an apparently brief while. The result is that, even 13.7 billion years later, light (emitted after inflation) still has not caught up (in certain places) with the distance separation created by space inflation.
A question that just popped to my head is this: in another 10 billion years, will people be still be seeing 'near first' light from 13+10 = 23 billion years ago? That is, will there *still* be light trying to catch up to the space separation caused by inflation, even after 23 billion years?
(Incidentally I don't believe in a big bang but rather a much older universe.)
quote:
Originally posted by subjectmatter
I have always understood there not to be any borders of the universe. That if you move sufficiently far from any one point you will in the end come back to it. This being because a particle follows straight vector in all four dimensions, but due to the curvature of space time, one perceives it as being a curve in three.
Yes most of us have heard that one, how space-time is 'closed', curving back on to itself, much as the surface of the earth does. However there is no observational evidence to support that idea as far as I've heard. Furthermore, lately we're hearing the idea that large scale space-time is 'flat', riding the fine line between being topologically 'open' and 'closed'. What to do?
Perhaps mainstream science may one day abandon the idea that space-time is curved at all, and work with the old premise that it's euclidean. (Even Einstein expressed doubts as to the correctness of his curved space-time gravity idea.) Granted, *something* is curved around matter, but it may be the quantum energy sea upon which light propagates and not space itself.
Mark |
|
|
|
pleco
SFN Addict
USA
2998 Posts |
Posted - 09/13/2005 : 20:40:00 [Permalink]
|
quote:
Then space itself decides to inflate incredibly fast, far outpacing the speed of light for an apparently brief while.
I don't recall reading this anywhere...can you provide some links? |
by Filthy
The neo-con methane machine will soon be running at full fart. |
|
|
|
|
markie
Skeptic Friend
Canada
356 Posts |
Posted - 09/13/2005 : 21:27:27 [Permalink]
|
quote:
Originally posted by pleco
quote:
Then space itself decides to inflate incredibly fast, far outpacing the speed of light for an apparently brief while.
I don't recall reading this anywhere...can you provide some links?
Yikes, I just looked up Wikipedia and it says this:
quote:
For the period of time between 10-35 seconds and 10-33 seconds, it is believed that the size of the universe expands to a size of approximately 10-32 m to 10-22 m. Postulating the existence of inflation solves a number of problems which are described in cosmic inflation.
I was just reguritating what my idea of inflation was, but upon reading Wikepedia my idea is reduced to nonsense. Frankly I don't know where I got my idea. Obviously it is not what is refected in Wikipedia. My apologies for so badly misrepresenting inflation theory.
The alternative I suppose is that space is always stretching, appararntly just fast enough that light has difficulty catching up.
I would like to hear from someone who actually believes this stuff to share :)
Mark
|
|
|
|
Dr. Mabuse
Septic Fiend
Sweden
9688 Posts |
Posted - 09/13/2005 : 22:33:52 [Permalink]
|
It is not matter within the universe that is travelling away from us that makes up the expansion, it's the universe/space itself.
Imagine a rubberband with three or four painted dots equally spaced. Then slowly stretch the rubberband. Each dot will travel away from its neighbour dot a little faster than half light speed, but the net effect will be that the outermost dots will travel away from eachother quicker than light speed. The space between galaxy super-cluster expands uniformly. |
Dr. Mabuse - "When the going gets tough, the tough get Duct-tape..."
Dr. Mabuse whisper.mp3
"Equivocation is not just a job, for a creationist it's a way of life..." Dr. Mabuse
Support American Troops in Iraq:
Send them unarmed civilians for target practice..
Collateralmurder. |
|
|
|
pleco
SFN Addict
USA
2998 Posts |
Posted - 09/14/2005 : 04:30:06 [Permalink]
|
| Ah, I see that...I was not thinking in 3D. However, if the net effect is faster than the speed of light, how would the light from this explosion ever reach us...unless the expansion is slowing down. |
by Filthy
The neo-con methane machine will soon be running at full fart. |
|
|
|
|
Ricky
SFN Die Hard
USA
4907 Posts |
|
|
Dr. Mabuse
Septic Fiend
Sweden
9688 Posts |
Posted - 09/14/2005 : 13:44:38 [Permalink]
|
quote:
Originally posted by pleco
Ah, I see that...I was not thinking in 3D. However, if the net effect is faster than the speed of light, how would the light from this explosion ever reach us...unless the expansion is slowing down.
Because the light originates from a time when matter was unifomly (relatively speaking) distributed throughout space not in galactic clusters of today. Thus the light comes from all of space.
Photons that came from places closer to us already reached us long ago. What we see now are only those photons that had a long way to travel here. (now that you mastered 3D thinking, try 4D -- the time-aspect. We are observing a snapshot of what happened 12.6 Bya, but we can only see what happened at that distance away.
As the photon is travelling through the space that is expanding, the photon is expanding too. It is getting stretched. This means that it's wavelength is increasing, frequency is decreasing, and the light shifts from blue to red. From red to infra-red, from infra-red to microwave. The light from all matter that glowed when the universe became transparent, has faded into microwave background noise.
|
Dr. Mabuse - "When the going gets tough, the tough get Duct-tape..."
Dr. Mabuse whisper.mp3
"Equivocation is not just a job, for a creationist it's a way of life..." Dr. Mabuse
Support American Troops in Iraq:
Send them unarmed civilians for target practice..
Collateralmurder. |
|
|
|
pleco
SFN Addict
USA
2998 Posts |
Posted - 09/14/2005 : 14:52:53 [Permalink]
|
| I think I get it now. Thanks for being patient with me :-) |
by Filthy
The neo-con methane machine will soon be running at full fart. |
|
|
|
|
 |
|
Topic Locked
