Sylvia Else wrote:
"Greg Neill" wrote in message
. ..
Ken S. Tucker wrote:

Are you guys painting yourselves into a corner? I think so.
Sam, when you say, "cannot see", you're presuming no EMR can
be received from Galaxy 1 to 2, yet Hubbles constant only red shifts.
We shouldn't find them moving at relative speeds greater than "c",
otherwise toss out SR and the Conservation of Mass-Energy Law,
as has been already done.
The Hubble constant tells us how fast space at a
given distance is expanding away from space at our
location. The matter in space moves along with this
so-called "Hubble Flow". This is why we say that
space is expanding.

Relativity does not place constraints upon how fast
regions of space may be moving with respect to
each other, only on how fast anything may move *in*
space.

It places constraints on how fast things can be moving relative to us.
In particular, that they cannot be moving at more than c relative to us,
though two objects in our frame of reference may be separating at mroe
than c (thought not more than 2c).

The only constraint is on the motion of things in space.
Things beyond the cosmic horizon can certainly be moving
away at greater than c, but of course we will never be
able to observe them since the space they're in is moving
away at greater than c and nothing can get 'here' from
'there'.



Space beyond about 13.7 billion light years in any
direction is moving away from us at greater than c,
so light from anything past that distance will never
get here. That is our 'cosmic horizon'.

They may be outside our light cone as a result of inflation in the early
universe, but that doesn't mean they're receding at more than c - just
that the light from them hasn't had time to reach us since the big bang.

No, light from there can *never* get here no matter how long
you wait. The space its in is being carried away faster
than the light can move towards us.