Quote:
Originally Posted by sjastro
That would only be true if we lived in a matter dominated flat Universe where the Universe expands forever but at a decreasing rate until it reaches an asymtopic value.
Since the expansion of the Universe has been recently found to be accelerating the opposite is true. The Universe is becoming progressively more "unobservable" as more and more distant objects slip beyond the event horizon as the recession velocity of these objects due to space-time expansion exceeds the speed of light. Unless space-time expansion slows down these objects will never be observed again.
A fundamental problem with cosmological string theories is that multi-dimensional space is a solution for flat space-time.
One possibility of an accelerating universe is that space time rather than being flat has an open geometry. How do the cosmological string theories deal with this?
Regards
Steven
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Yes that's correct, given that the universe appears to have an accelerating expansion, more and more of the Local Universe will slip over the event horizon and disappear off into the distance. But that is also predicated on the belief that this accelerated expansion is in fact a real phenomenon and not some illusion created by other factors, such as an imperfect understanding of supernova dynamics and evolution, unobserved dust and gas between the supernovae and ourselves, or some other effect we're as yet unaware of. Although, using Occam's Razor, it most likely going to be a real effect of expanding spacetime. So therefore what is being observed is real and means things are picking up pace.
It looks as though a theory of Quantum Gravity is needed to account for acceleration, if I understand what I'm reading. I haven't read up on this for quite awhile, so I'll have to acquaint myself with the latest literature. Here's a site to look at...
http://www.damtp.cam.ac.uk/user/gr/public/qg_qc.html
There's bucket loads of articles and sites to goto, so it'll take some time to absorb everything.