🚀 go-pugleaf

Earlier, I wrote:

>> the solar system has about 20 orders of magnitude higher matter density
>> than the universe.  If much weaker matter densities will cause space in
>> the universe to eventually contract, why doesn't it cause space in the
>> solar system to contract now?

and schumach@convex.com (Richard A. Schumacher) replied:

> Good golly, is it really necessary to state this? The angular momentum of
> the solar system keeps it from collapsing! Without it, the solar system
> would collapse in a few years. Same argument for superclusters, etc. The
> universe, OTOH, appears to have negligible net angular momentum, but also
> has much lower average density.

     Indeed, you state the obvious, which I think no one has overlooked.
The effect of gravity on matter is well-studied and well known.  To a first
approximation, it is Newtonian in its behavior.  Your remark refers to the
effect of gravity on matter.  That is not part of the dilemma we were
discussing.

     My question above refers to the effect of gravity on spacetime, as
hypothesized by the big bang theory and described in GR.  The gravity of
the universe has no net effect (so far as we know) on galaxies or any other
matter in the universe.  (If it did, in what direction could it possibly
act if the big bang had no center?)  In particular, it does not make
galaxies move through space (see other concurrent messages).  But it does
have a retarding effect on the expansion of spacetime.  But spacetime has
no angular momentum that we know of, either in the universe at large or in
the solar system.  So your argument is inapplicable to my question.

     Implicit in my question is the assumption that if local spacetime
expanded or contracted, that would add or subtract space between the Sun
and the planets.  So we could detect such a change by measuring the
distances of planets, just as we detect cosmological redshift by measuring
galaxies.  -|Tom|-

-- 
Tom Van Flandern / Washington, DC / metares@well.sf.ca.us
Meta Research was founded to foster research into ideas not otherwise
supported because they conflict with mainstream theories in Astronomy.