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Originally Posted by cwjohn
Through gravitation attraction the galaxy will tend to all move at the same speed.
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Could you please explain this ? (I'm not sure I understand where you're coming from).
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Originally Posted by cwjohn
Expansion of space will result in the galaxy moving at c relative to our timeframe at sometime in the future,
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Interestingly, we already see many galaxies moving at, or greater, than c. The fastest observed so far is UDFy-38135539 z = 8.55, discovered in 2010, it is the most remote object known.
It has been calculated, (as of October 2010), to have a light travel time of 13 billion years, with a present comoving distance of around 30 billion light-years. The galaxy is thus the most distant object yet identified in the universe. It may be possible to observe galaxies up to redshift of 10 with the current generation of telescopes.
(A generally accepted cosmo model shows that galaxies beyond a redshift of z=1.46, recede faster than c).
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Originally Posted by cwjohn
thus when the photons reach us it should appear as if the entire galaxy blinks out. Of course it will be many tens of billions of years until those photons reach us, so dont hold your breath that you will see galaxies disappearing any time soon.
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As I mentioned in my previous post, the things we should see is still up for debate amongst theorists. I’d like to keep my mind open about this one. Especially as the technology isn’t ready yet to confirm it, one way or the other.
For example, UDFy-38135539 presently looks like a
‘smudge’.
… Interesting stuff ..
Cheers
PS: The CMBR is z~1100. The recessional velocity is 3.2c. At the time of CMBR emission, the recessional velocity was 58.1c (there are some model assumptions in these figures). [Reference: Lineweaver and Davis]
Also, looks like the James Webb telescope should be able to detect galaxies more than 13.4 billion light years away (Wiki).