[ExI] Who's stealing our universe?
pharos at gmail.com
Wed Sep 24 16:19:37 UTC 2008
On Wed, Sep 24, 2008 at 2:39 PM, Lee Corbin wrote:
> Not unreasonable, or---so far as I can see (pun not intended)---
> at all mysterious, but rather to be fully expected.
> Don't confuse the "bubble" of our universe with the observable
> universe, (and naturally not the latter with the homogenous
> extend of a much smaller volume). For all we know---and Tipler
> and others so believe---our universe is infinite. We only get to
> see the infinitesimal region that light has had time to get across.
> But if some other guys are about 21 billion ly away, then we're
> half way to the *edge* of what they can see, and they ought
> not be surprised if a religious prophet were to tell them that
> off in our direction was matter affecting visible matter in that
> direction. The prophet would be right!
> According to the brilliant April 2003 Scientific American article
> by Tegmark (which is on-line but I don't have the link right now),
> our "bubble" is indeed infinite. I believe it to be common to refer
> to our bubble as infinite.
Another article interviewed the scientists involved in this discovery
and apparently they were quite surprised by theses unexpected
"We found a very significant velocity, and furthermore, this velocity
does not decrease with distance, as far as we can measure," Kashlinsky
told SPACE.com. "The matter in the observable universe just cannot
produce the flow we measure."
The scientists deduced that whatever is driving the movements of the
clusters must lie beyond the known universe.
A theory called inflation posits that the universe we see is just a
small bubble of space-time that got rapidly expanded after the Big
Bang. There could be other parts of the cosmos beyond this bubble that
we cannot see.
In these regions, space-time might be very different, and likely
doesn't contain stars and galaxies (which only formed because of the
particular density pattern of mass in our bubble). It could include
giant, massive structures much larger than anything in our own
observable universe. These structures are what researchers suspect are
tugging on the galaxy clusters, causing the dark flow.
"The structures responsible for this motion have been pushed so far
away by inflation, I would guesstimate they may be hundreds of
billions of light years away, that we cannot see even with the deepest
telescopes because the light emitted there could not have reached us
in the age of the universe," Kashlinsky said in a telephone interview.
"Most likely to create such a coherent flow they would have to be some
very strange structures, maybe some warped space time. But this is
just pure speculation."
Though inflation theory forecasts many odd facets of the distant
universe, not many scientists predicted the dark flow.
"It was greatly surprising to us and I suspect to everyone else,"
Kashlinsky said. "For some particular models of inflation you would
expect these kinds of structures, and there were some suggestions in
the literature that were not taken seriously I think until now."
The discovery could help scientists probe what happened to the
universe before inflation, and what's going on in those inaccessible
realms we cannot see.
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