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Cosmo Novice
Cosmo Novice is offline
#2
Mar20-12, 10:41 AM
P: 366
Quote Quote by Daniel Batt View Post
OK, I am brave enough to risk sounding like some kid who doesn't get secondary physics, let alone tertiary physics, with this question, but please bare with me.

Given galaxies at the edge of the horizon of our universe appear to be accelerating away from us at greater velocities, surely we know that it is at least possible that it is us who is accelerating away from them at increasing velocities (yes, I know there is no pure observer since Einstein).

Since a body at 12 billion light years from earth is speeding away so quickly, surely, with the rate of expansion of the universe increasing, our galaxy must be travelling at this rate from these distant galaxies at an exponential rate right now, given we have been part of this increasing acceleration for the past 12 billion years.

The inflationary period is a very short time period, so we can't be looking back into it.

So would it not be correct to look at a distant source like UDFy-38135539 and assume that we are now accelerating away from it at an exponential speed way higher than the red shift was measuring 12 billion years ago?

Please forgive what might seem like an childish mistake.
We are not accelerating within our own reference frame. We are at rest with regards to the CMB, which any other observer will observe from their FoR (Every galaxy is the center of its own OU with expansion moving outwards.)

Distant galaxies can be receeding from us >c. As to them we would also appear to be moving >c. There are no prerferential reference frames though - so while we can observe expansion >c this is not "acceleration" through space so GR still holds up.

Hopefully we will get some knowledgeable posters here as this is something I would like to explore a little bit further.