[ExI] Question on Vacuum fluctuations and Non-Zero EnergyEmptySpace:

[scerir]

Bryan:
However, what about the expansion of space?
If there is a finite amount of energy and mass,
then the vacuum fluctuations should be increasingly
less localized. Right?

#

Imagine removing from the universe the matter,
the radiation, and the other exotic stuff.
The resulting content is vacuum, the unobservable
lowest possible energy state. 

There are many effects which contribute to the total 
vacuum energy, including vacuum fluctuations (if energy 
conservation is violated when the particles are created, 
then all of that energy is restored when they annihilate 
again, and according to a vacuum conservation theorem, 
at a classical level the vacuum must be stable against 
spontaneous matter creation processes). 

Essentially the effect of vacuum energy is to contribute 
to the universal expansion, and not to the self-gravity 
effects. 

A quintessential possibility is that the vacuum energy 
changes with time. In this case, the problem of 
conservation/localization of vacuum energy may find 
a solution (ecological too).

Another possibility is a sort of inflationary scenario. 

The best possibility seems that the expansion is fueled 
by our lack of understanding :-)

I did not check Ned Wright
http://www.astro.ucla.edu/~wright/cosmolog.htm
or Sean Carroll
http://www.arxiv.org/abs/astro-ph/0004075
http://www.arxiv.org/abs/astro-ph/0310342
maybe you can find something there.