Dark Matter - A stray Thought

"Fleetie" wrote:
2) [...]
It would be interesting to simulate the effect
on planeteray orbits as the "strength" or "density" of the
pervasive gravitating matter field were increased from zero to
something comparable to that of "normal" matter. I'm not well-
enough-informed (or clever?) enough to make much of a guess at the
result as the density becomes large.

Having thought about this some more, it's cecome apparent that
there is a "limiting" case worthy of consideration, which may at
least yield some hints:

Assume that all bodies constituting the hypothetical solar system are
of equal mass density rho_s. Immerse them in a gravitating "sea"
equivalent to mass rho_amb. When rho_amb=0, we have the case as we
are used to considering our own solar system.

As rho_amb increases, there will be a point where rho_amb=rho_s.
What happens then? Then everything is of the same "gravitational density",
so it would appear that there would be no force to keep the planets
in their orbits, though this is only true if the ambient "sea" does
NOT penetrate the mass of the planets themselves (neutrinos _do_).
I think I've just trodden on my own conjecture there.

Still, it's interesting as a hypothetical case.

Perhaps even more interesting is the case where rho_amb rho_s.
It's not clear to me what the gravitational interaction would be
between two spherical (not that it matters much) "holes" in a medium
of greater gravitational density.

Also, it would seem that the distribution of the "dark matter" ought
not to be _entirely_ uniform throughout the universe; it must be higher
within galaxies, else it wouldn't have the effect that it does on
them.


Martin - thinking out loud, really.
--
M.A.Poyser Tel.: 07967 110890
Manchester, U.K. http://www.fleetie.demon.co.uk

Having thought about this some more, it's cecome apparent that

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Having thought about this some more, it's cecome apparent that

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