Re: Gravity and levity

In article <[EMAIL PROTECTED]>,
[EMAIL PROTECTED] (Gordon D. Pusch) wrote:

>> The reason that I end up with the gravitational constant perhaps in
>> combination with other expanding "levity" forces is that I experiment
>> with the idea of a universe that is stable over time in terms of size,
>> but with a lot of "cosmological convection".

>Sadly, as others have already observed, a "cosmological constant" does
>=NOT= lead to a "stable" universe, convecting or otherwise; it leads to 
>an UNSTABLE universe that undergoes either runaway expansion or collapse.
>It is analogous to trying to balance a pencil on its point: The Universe
>"wants" to fall over into either an implosion or explosion.

I suggested that this might have to do with that it is originally a rigid
constant (i.e., does not change):

In some sense, any additions to the Lagrangian used to create the new,
extended GR Einstein-Hilbert equation (via a metric variation) will appear
as a dynamic form of the cosmological constant in the original
Einstein-Hilbert equation.

Since it varies as any other stress energy tensors, perhaps it should be
called the "cosmological variable", instead.

>> Suppose I experiment with a glob universe with essentially homogenous
>> overall large scale density. Then the formula GM/(c^2 r) sets the size
>> limit of each glob. Our glob, by your estimate, would roughly be the size
>> of the currently observed universe. But this would not work with many
>> globs interacting, so GM/(c^2 r) would need some levity counteracting on
>> that very large scale level.

>Then the individual "globs" would each collapse on themselves to form black
>holes, while each "glob" would be "pushed" away from every other "glob"
>apart by your "levity" force.

No, there seems to be at least two different levity forces in play here:
One responsible for the expansion of visible matter, within each glob, and
another to keep the different globs apart. The size of the glob would
depend on the density of region. The glob we live in is according to the
estimate Ulf Torkelsson made, about the size of the currently observable
universe. 

>You =CANNOT= have a stable situtation unless you postulate that at even
>LONGER distances scales that the "levity" acts, there is a "hypergravity"
>that increases even faster with distance than the "levity" force does.
>This will =NOT= stop the individual "globs" from collapsing under their
>own gravity, but it will at least keep the resulting hypermassive 
>black holes from running away to infinity.
...
>But at some point, you have to stop adding epicycles to "fix" the problems
>that your previous epicycle caused, and re-examine your fundamental axioms.

You seem to envision a generalized GR to be made by successively throwing
in new compensating factors.

By contrast, I envision a generalization of the GR Lagrangian, and then
one applies a metric variation to that. The post-metric variation equation
might then be very complicated, due to Lagrangian field interactions. 

This is not a very strange situation: Even within current GR itself,
methods of developing it by a succession of deformations have been
unsuccessful, because they become practically unworkable after a few
deformation steps only.

>_WHY_ should you assume a "levity" force in a misguided attempt to make 
>the Universe "stable" and "eternal," ...

Strictly speaking, I think about a universe that might have a series of
globs, each which its own life and life span, just as with every other
subcomponent of the currently observable universe. It is a universe that
would be much older and much larger than that of the current Big Bang
model predictions. The globs would not be stable, but considerably more
dynamic and perhaps also have a great deal of cosmic convection: Perhaps
the dark matter would not expand as uniformly as the visible matter.

If you take a glob of the size and density of our currently observable
universe, the estimate that Ulf Torkelsson by the formula GM/(c^2 r) says
that its expansion rate should start to contract as it is by observation.
This is currently interpreted as the "acceleration of the universe". I
then neglect the fact that looking further out also looks further back in
time. But if the universe, for some reason, hangs together in such a
model, it might make sense.

>... when all the evidence that we have
>strongly indicates that the Universe =ISN'T= stable and =ISN'T= eternal ?!?

The funny thing is that there is experimental evidence that contradicts this:

The Hubble telescope was pointed at a very small region that appeared to
be pitch black.

Then one found there a large number of very tiny galaxies. These galaxies
should be at the very outer edge of our currently observable universe.

The funny thing, though, with these tiny galaxies, is that they look fully
formed. Thus, when looking that far, the universe does not become older,
as it should be in a Big Bang model.

The source (again a BBC "Horizon" program :-) about the Hubble telescope)
did not say anything about the redshift of these tiny galaxies. Perhaps
they are too small to be individually measured by the Hubble telescope.

So there is some information suggesting that we might live in a glob, if
those tiny galaxies, or some other, even tinier, turn out to be outside
it. This could be say if they turn out to have a completely different
redshift relative the Big Bang model, i.e., the redshift expansion of our
glob.

This is a question that currently cannot be resolved by current Big Bang
theories or observations. So to settle it, one probably must build better
telescopes.

  Hans Aberg

[Mod. note: the claim that distant galaxies in the Hubble Deep Field
appear to be `fully formed' seems wrong to me -- mjh]