If we had an optical device that was powerful enogh, could we look out into the cosmos and see the Big Bang? Since our best estimates of the age of the Universe are about 15 Billion years, then it follows that if we could see light from 15 Billion light years out, then that light would be from the "flash" of the Big Bang. Is my reasoning correct here?
If so, then to see the Singularity that started it All, then we would need to look to the extreme of bigness. I have trouble with this, to see the tiny point we need to look as far as we can?!?
Any help with this would be apreciated.
Skott
If so, then to see the Singularity that started it All, then we would need to look to the extreme of bigness. I have trouble with this, to see the tiny point we need to look as far as we can?!?
Any help with this would be apreciated.
Skott
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Re: Big Bang Paradox
Thu, November 2, 2006 - 11:15 AMI believe you are more-or-less correct theoretically. As a practical matter, there are undoubtedly limits. From what I understand (this is not my area of expertise) it seems highly unlikely that light from the early years of the universe "survived". By that I mean to see back to (or really near) the beginning of the universe, you would need to observe a fair amount of light that was emitted by an object from that time, and then traveled undisturbed ever since. At some point early on, I imagine the universe was just too dense and there was too much going on for that to happen. In fact, according to Wikipedia, there is a so-called "surface of last scattering" when the universe was about a few hundred thousand years old.
Here's a link that might be of interest: map.gsfc.nasa.gov/m_uni/uni...test3.html
There are some issues with inflation in there, too. If the original inflation started out such that distances grew slowly enough, oddly enough, the light from that period would have already passed us by. It wouldn't be until later that objects would be distant enough for light to have to play catch up. This depends a lot on how inflation happened, which I don't know much about. To put that another way, if the universe hadn't "grown" but was just it's current size, we would not actually be seeing very far at all. From what I've read, current estimates suggest the universe is somewhere in the many tens of billions of light years across, much larger than the 12-14 billion years age estimate. If the universe had always been at its present size, we would only be able to see a fairly small fraction of it (assuming the current age estimates remained correct). -
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Re: Big Bang Paradox
Thu, November 2, 2006 - 1:59 PMVery interesting, thank you for the reply. -
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Re: More Big Bang Paradox
Tue, March 13, 2007 - 3:09 PMIf the universe emerged from a singularity in an event like the Big Bang, how did all the light and energy overcome the gravity that must have been present with the totality of the universe in a single point? The force of the bang had to be tremendous to overcome the gravity. I am having trouble seeing how this happened, since the speed of light is a constant. -
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Re: More Big Bang Paradox
Fri, March 16, 2007 - 3:17 PMBelieve it or not, this is one of those few cases where you get to ignore the speed of light. The current leading theory (as I understand it) suggests that the early universe went through a period of rapid inflation. The driving elements behind this are still rather speculative, I think (I have to say, I have to smirk a bit when I read about the "inflaton" particle theory).
The key thing to understand here is that the universe expanded (inflated), but it didn't expand in the way the typical analogies would lead you to envision. The universe doesn't need to expand in to anything (like a balloon needs space to expand), nor is there some sort of material undergoing expansion (again, unlike the rubber balloon, the space-time manifold is not made of anything). That would have some nasty implications. Rather, literally what happens is that the distance between two points simply gets bigger. It turns out that it is perfectly acceptable for the distance between two points to get bigger such that their apparent velocity relative to each other is faster than light. It's not that an object is moving faster than light, it's the points in space themselves. -
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Re: More Big Bang Paradox
Mon, May 21, 2007 - 9:02 PMI pointed this out in my Relativity tribe a while ago as well. Also, if you were to see the Big Bang in such a manner, you would be able to see it regardless of which direction you looked. Also, universal expansion tells us that the Big Bang happened right here where we are, and that is true for every point in the universe. -
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Re: More Big Bang Paradox
Tue, June 19, 2007 - 9:39 PMTo add to some of this, the first light we see after the "big bang" is the microwave background radiation.This is the after glow that we can see. This started when the density of the universe would allow light to exist, or about 300,000 to 400,000 years after the begining. Neutrinos come from further back but given that they are so hard to detect and so thined out by now, we don't really see them.
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