Re: Creation (long)

[Jim Green <JMGreen@sisna.com>]

At 06:55 AM 12/5/97 EST, David Bowman wrote:

Well, I was hoping that David Bowman would chime in, but I didn't expect the
bells to deafening. (:-)  Like an elephant, it will take some time to digest
this.  Let me begin at the end -- where I need to be sure that I have the
correct concept:
Dan:
> > "Moving apart" and "distance between them is getting bigger" are
> > synonymous, though neither is a "reason" in the causal sense.

David:
> These concepts do not have to be synonomous.  I think in the context in
> which Jim was trying use these concepts is that he meant "moving apart"
> to refer to motions that increase the separation between objects as
> denominated in comoving coordinates (i.e. an increasing comoving coordinate
> spatial separation with time), and he meant "distance between them is
> getting bigger" as meaning that the physical proper spacelike geodesic
> distance between the objects increases from one spacelike time slice to the
> next spacelike time slice.

Yes this is what I was referring to -- and I don't know what lay language to
use -- Folks help me out here.  As the rubber sheet expands the distance
between the ants grows, but the ants are walking too -- such that if the
expansion were to slow or stop, the ant-ant distance would still increase. 

But there is still a problem in my head:

You say that as the Universe expands that what ever "stuff" was at the rim
of the Universe shortly after the BB has always remained relatively close to
that "rim" (whether we are talking about balloons or rubber sheets of what
ever dimension)  -- eg your ants stay close to the "edge" .  But didn't the
Universe "expansion" initially proceed at a rate >c?  The "stuff" even
photons can't travel at >c.  I am confused.  In my head the "rim" traveled
faster than the stuff and later (I don't know what "later" might mean) this
expansion slowed down to <c (at least in some scenarios) such that the
photons are "catching up" to the "rim". And if the expansion slows to <<<c
even the galaxies would "catch up"

Where have I gone wrong?   

J