Re: Branes and gravity

On Tue, 21 Oct 2008 09:25:35 +0200, Eivind <eivindorama@xxxxxxxxx> wrote:
| George W Harris skreiv:
|
|> That question becomes how matter in a universe
|> with only gravitation would behave. Would it clump? If so,
|> so would dark matter (that is, matter in all branes would
|> tend to clump in the same places).
|
| I don't see how it could. For clumping, gravity is not sufficient, you
| also need to dissipate the energy SOMEHOW (i.e. some kinda friction or
| something)
|
| If there's only gravity, I don't see how the energy could dissipate, so
| I don't think matter would clump. Every particle would move on an
| independent trajectory, determined by the positions of all other matter,
| but it could not lose momentum and clump up. Because there'd be no tidal
| stresses, no collisions, no nothing.


There would be collisions within the fraction of matter in the same
brane.

Tidal stress is weird. While it is just gravity, it depends on one part
of a body being further away from the gravity source than other parts,
and the resultant gravity gradient. What direction is a different brane
in? Let alone trying to sum the effects of multiple branes. Probably
adds up to about the same from all "directions" so no gradient.


--
Reverend Paul Colquhoun, ULC. http://andor.dropbear.id.au/~paulcol
Asking for technical help in newsgroups? Read this first:
http://catb.org/~esr/faqs/smart-questions.html#intro
.

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