Darren New <dne### [at] sanrrcom> wrote:
> >   (Anyways, I think that the reason why the universe must be expanding
> > rather than all galaxies receding from us simply because they got an
> > initial velocity away from the center is that in the latter case all the
> > galaxies would be receding from us at the same speed regardless of
> > distance, while in an expanding universe the farther away from us the
> > galaxy is, the faster its recession speed, which is what is observed.)

> Unless the galaxies all exploded out at different speeds, so of course the 
> ones farther away are receding at higher speeds. ;-)

  However, in an expanding universe the recession speed accelerates
(because the more the galaxy recedes, the larger the distance from us,
and hence the larger the recession speed). In a situation where the
galaxies simply got an initial speed the recession would be constant.
(Well, in fact that's not true: The recession speed would actually be
decelerating because they are slowed down by the gravity of all the other
galaxies.)

  It then comes down to whether we can measure whether the recession speed
of a galaxy is accelerating or not. (Can we?)

-- 
                                                          - Warp

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