Hi Paul! :-)

 PR> It should be detectible instrumentally at least, but what 
 PR> should happen is mass would be attracted and collect.  Thus mass 
 PR> concentrations should basically match between parallel universes.
And the problem with that is?

 PR> So what keeps the
 PR> first 2-D universe from detecting all those masses from neighbors.
Well, how would you distinguish the gravitons from "here" from
gravitons from "there"? They would come from the same place and
thus it looks like they all were generating by mass in the first 2-D
universe.

Also, it would depend a lot on how well gravitons travel between universes.
Maybe they lose a lot of energy so that gravitons from rather light objects
(say, a planet) don't make it. That would mean that galaxies and clusters
would be in the same spots in parallel universes, but stars and planets
don't have to be.

 PR> Summed, you've got as much gravity as if the gravitons never left it 
 PR> in the first place.
Yep. No way to find out which is really happening. Unless significant mass
were on the move (and quickly) in one of the universes, in which case you
could detect gravitons where no mass is. Since galaxies don't move about in
unexpected ways, no such moving mass will probably exist. Regular movement
does not count since that would be going on since millions of years and the
masses in different universes would have synchronized their movement long
ago.

Ciao
Pascal

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