Re: [Phys-l] Hubble Law

[John Denker <jsd@av8n.com>]

On 01/18/2007 12:38 PM, Rick Tarara wrote:
>   My question is why?  Why does the space between galaxy's, 
> between stars, expand but not the space between molecules, between atoms, 
> between nucleons?

The atoms, molecules, rulers et cetera *would* expand if they
were not bound by chemical bonds et cetera.

Indeed you could say that they do expand a tiiiny bit, in response
to the overall cosmological acceleration ... but before they have
expanded very much, the springiness of the chemical bond provides
a countervailing acceleration, so there is no /further/ net
acceleration and no /further/ expansion.  The total effect
is unobservably small, because the cosmological acceleration
is so small, and the spring constant of the chemical bond is
so large.