John Clark wrote:
On Sun, Oct 26, 2014 Bruce Kellett <[email protected] <mailto:[email protected]>> wrote:>If there is more that a very small amount of dark energy, then a beam of light can never get right round the universe (the universe does not re-contract in that case OK.>it expands for ever even though closed). So you can never see theback of your own head.Obviously if it expands forever you could never see the back of your head, and our universe is not only expanding its accelerating; but how could you call such a universe closed?
It has a finite extent, even if expanding exponentially. The point is that the intrinsic curvature is positive in the case under discussion, which is what we mean by a closed universe.
Bruce
John K Clark
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