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View Full Version : Gravitational effects of neighboring parallel universe objects explain 'Dark Matter'?



SWDude23
2010-Jul-28, 02:42 AM
It probably has been discussed before, but I thought I'd just ask....

If the 4th dimension is made up of an infinite 'stack' of 3rd dimensional universes, could a neighboring 3rd dimensional object's gravitational effect somehow be felt in our universe? Would this explain the 'Dark Matter' and its gravitational effect we assume is in galaxies enabling them to spin with the unexplained speeds we see?

Shaula
2010-Jul-29, 07:06 AM
Probably not. Galactic rotation curves are just as expected near the centre. They only go wrong further out.

OK you could argue that if gravity propagated in some wierd way then it might but that'd be making up very complex explanations just to fit the idea.

caveman1917
2010-Jul-30, 02:22 AM
The 4th dimension would actually be time, so it is indeed made up of a 'stack' of 3dimensional universes, but the same universe -- ours. Just at different moments in time.

But you are probably asking about even higher dimensions, would gravity 'leak' in higher dimensions? And would neighbouring universes have gravitational effect on ours, and we on them?
First of all it is important to understand that such higher-dimensional theories are purely hypothetical at this point.

There is something being suggested akin to what you describe, string theory with 'large extra dimensions' (as opposed to 'curled up' ones).
Neighbouring branes (universes) would indeed have gravitational effects on our brane, and vice versa. The whole idea is still speculation up to this point though.
You might want to google 'brane cosmology'.

Wether this explains dark matter is a whole other issue though. Nothing seems to suggest so, since the distribution of dark matter seems to be intrinsically bound to the structures we know exist inside our own universe.

Shaula
2010-Jul-30, 08:41 AM
I assume the fourth dimension = time in my reply.

What you are asking is basically "If we are allowed to assume any arbitrary distribution of matter that can only interact with us via gravity then can we explain dark matter". Yes since the first part is basically the definition of dark matter! Unless it turns out to be weakly interacting too. If that is the case then the idea of leaky gravity would seem to have a large hole in it. But for now we have no idea and no easy way to test it.

@Caveman
If the other brane interacted with us gravitationally you'd expect thing there to be 'bound' to structures in our universe. Or more accurately for the two universes to be approaching a minimum energy configuration for their matter distribution.

caveman1917
2010-Jul-30, 10:53 AM
@Caveman
If the other brane interacted with us gravitationally you'd expect thing there to be 'bound' to structures in our universe. Or more accurately for the two universes to be approaching a minimum energy configuration for their matter distribution.

Yes i was considering a dynamic environment, with branes passing by and floating away, not a 1-to-1 scenario.