Re: Expansion = inverse contraction?

2003-12-14 Thread Russell Standish
I'm not sure you're phrasing this correctly. What you mean is to ask
whether our measuring sticks are contracting rather than space
expanding. Since the metre is defined by a certain number of
wavelengths of light radiated by a particular element, this would be
equivalent to asking whether certain atomic properties (e, c, hbar etc
- are changing over time).

However, I'm not sure that there is any meaningful way to ask
questions about change to "measuring sticks", only to dimensionless
ratios such as the fine structure constant (which has changed by a
small amount over the life of the universe).

Cheers

On Sun, Dec 14, 2003 at 12:25:12PM +1100, Colin wrote:
> Something that occurs to me that I haven't seen any explicit discussion
> about and thought someone in the list may have come across it somewhere.
> 
> In cosmology we traditionally think of the universe as expanding from
> the point of view of any position within it. In our minds it is getting
> bigger and bigger.
> 
> I am asking why I haven't ever seen anyone discuss the inverse
> proposition .ie. That what may be happeneing is that this expansion is
> only an appearance and that it may be that spacetime is actually
> contracting. If it were contracting then from within everything would
> appear to be expanding as we shrink and shrink to nothing.
> 
> This is not a 'big crunch'. This is an inverse-bang. 2nd law/fwd time
> etc still functions as usual.
> 
> Is there something built into the models that forbids this that I simply
> haven't got? 
> 
> Or is it meaningless to make the distinction?
> 
> Cheers
> 
> Colin Hales
> 

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Expansion = inverse contraction?

2003-12-13 Thread Colin
Something that occurs to me that I haven't seen any explicit discussion
about and thought someone in the list may have come across it somewhere.

In cosmology we traditionally think of the universe as expanding from
the point of view of any position within it. In our minds it is getting
bigger and bigger.

I am asking why I haven't ever seen anyone discuss the inverse
proposition .ie. That what may be happeneing is that this expansion is
only an appearance and that it may be that spacetime is actually
contracting. If it were contracting then from within everything would
appear to be expanding as we shrink and shrink to nothing.

This is not a 'big crunch'. This is an inverse-bang. 2nd law/fwd time
etc still functions as usual.

Is there something built into the models that forbids this that I simply
haven't got? 

Or is it meaningless to make the distinction?

Cheers

Colin Hales