29 June 2007

Most fun I had reading today:

We live in a very special time in the evolution of the universe: the time at which we can observationally verify that we live in a very special time in the evolution of the universe.

Context: A soon-to-be published paper, The Return of a Static Universe and the End of Cosmology (via Ars Technica). The basic idea here is that as the universe continues to expand, and things get further apart, and light dopplers beyond our detection abilities, the only things we'll be able to see will be our local neighborhood of galaxies, still bound together by 'gravitational' forces. For related reasons, the wavelength-shifted cosmic background radiation will have diminished, and will be indistinguishable from interstellar noise. Thus, the perceivable universe at this point (100 billion years from now) will look a lot like what we could see before we learned to measure Hubble expansion and learned about the Big Bang in the first place. So, if a new universe-pondering species were to come of age in this era, they'd never find out that their galaxy cluster wasn't the entire universe.

As a non-physicist, I think this is interesting for a couple of reasons. First, it's curious to think that if anyone was around 100 billion years ago, the universe probably made much more sense to them, since the evidence was that much less attenuated. Second, it seems to violate the rule that information is always preserved in physical interactions -- since the information is still there, in the form of propagating waves of light, it seems like it ought to be possible to detect it somehow, even if our current detection techniques aren't up to the challenge. But to reiterate, not a physicist, so feel free to correct this perception.

1 comments:

Rodrigo said...

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