In a message dated 3/12/2009 12:06:50 AM Eastern Daylight Time,
FrankReed@HistoricalAtlas.com writes:
Anthony, you wrote:
"Isn't there a "maximum" density for matter? I mean, stuff is composed of
fundamental particles which supposedly have mass and take up space."
Hmm. But where does it say that fundamental particles take up space??
Electrons and quarks have no meaningful size.
Another poster said that you shouldn't take the infinite density seriously
because GR and QM haven't been unified yet. Sure, that's a good point. But at
what time after the Big Bang is that irrelevant? Ten times the Planck time?
And so what density for matter would we have to deal with realistically. By
the standard model of its origin, the universe was mighty dense a tiny fraction
of a second after the Big Bang, and there's little reason to expect that
"quantum gravity" will undo that.
-FER
)))))))))))))))))))))))))))))))))))))))))))))
Actually you probably shouldn't take space time very seriously in this early
regime. Space time seems to be an emergent property due perhaps to the
Decoherence of the gravity field. This explains the success of the semi classical
formalism. In essence the gravity field is space time. We shouldn't expect a
continuum to exist on the order of the Planck scale. This is certainly true
in Loop Quantum Gravity and is also true operationally in String theory. In
fact in String theory the Einstein equation takes a perturbative form which
suggest that space and time are emergent properties of some pre geometric
structure. The problem here is applying the semi classical formalism in regimes
where it no longer correctly describes the Universe. Singularities means your
model has failed, not that there exist a real infinite density.