From: Anders Sandberg (asa@nada.kth.se)
Date: Thu Aug 15 2002 - 01:21:29 MDT
On Thu, Aug 15, 2002 at 04:31:15PM +0930, Emlyn O'regan wrote:
>
> See, this is where I haven't been paying attention to physics. If space
> itself can expand, rather than the things in it merely getting further from
> each other, how can we perceive that?
Image that you are looking at a pulsar emitting regular flashes. If the
pulsar is moving away from you at a constant speed you will just see
regular flashes (due to relativity at another frequency than the pulsar
is flashing in its rest frame). But if space between you and the pulsar
is growing, then it will grow while the light is traveling through it,
and this will make the flashes appear to come later and later - there
would be a decrease in frequency over time as seen by you. A
sufficiently fast space expansion would lead to a Zenon-like effect
where the distance the light had yet to travel remains constant or
grows, making it never reach you.
-- ----------------------------------------------------------------------- Anders Sandberg Towards Ascension! asa@nada.kth.se http://www.nada.kth.se/~asa/ GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y
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