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Re: Sci. Am. Frontiers

Yes. This is one of the more precisely measured values in physics.
The cosmological constant (which is effectively the vacuum energy
contribution to Einstein's field equations) must be zero to an
accuracy of 120 decimal places in order to be consistent with
observational data on the expansion of the universe.

WHY that is true is another matter and is still an unsolved problem.
All inflationary models (last time I looked) predict enormous
cosmological constants which must be banished through a combination
of handwaving and wishful thinking. I developed one a while back in
which the constant naturally vanished shortly after the inflationary
phase but it involved some other out of the ordinary assumptions as
well.

The Casimir effect depends on a *difference* in ground state energies
between the enclosed region between the plates (with a countably
infinite number of normal modes) and the region outside with an
uncountably infinite number of modes. Causing a difference in energy
says nothing about the energy you made a difference *from.*


Now I'm very confused. Is this low value for ZPE part of normal physics?
I was under the impression that various theories predict different values
for the energy density of the virtual particle sea, but all on the order
of the energy density of the nucleus (or much more.) This is old Feynman
stuff from decades ago, no? It has always been my understanding that
conventional, conservative scientists agree that "free energy devices" are
ridiculous NOT because the ZPE density is low, but because there is no
easy way to make macroscopic use of the ZPE (other than by things like
Casmir effect on parallel conductive plates.)

Now here's the Scientific American debunking the search for ZPE-tapping
devices by implying that physicists believe the energy contained in the
vacuum to be uselessly small. If this is not a majority opinion in
physics, then it sounds to me like SciAm is itself adopting one "crackpot"
viewpoint in order to debunk another. No fair!


.....................uuuu / oo \ uuuu........,.............................
William Beaty

Paul J. Camp "The Beauty of the Universe
Assistant Professor of Physics consists not only of unity
Coastal Carolina University in variety but also of
Conway, SC 29528 variety in unity.
pjcamp@coastal.edu --Umberto Eco
pjcamp@postoffice.worldnet.att.net The Name of the Rose
(803)349-2227
fax: (803)349-2926