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Re: expansion of the universe



J Montgomery wrote:

If everything scaled the same we wouldn't be
able to detect a change in distance, would we?

Right. It would be the mother of all gauge invariances.

You could invent your own theory that says everything
increases 10% on Thursdays. Nobody could disprove it.

=============

There is no reason to expect ordinary things to
expand just because the universe is expanding.
The size of atoms is always going to be something
on the order of a Bohr radius, which we can calculate
in terms of things like hbar and the mass and charge
of the electron.
http://physics.nist.gov/cgi-bin/cuu/Value?eqbohrrada0

If I'm an ant living on a balloon and somebody is
blowing up the balloon, there's no particular reason
to expect that they're messing with hbar or m_e or
q_e or eps0 at the same time. It would be a bizarre
coincidence, at best.