Hello, I saw a programme on Channel 4 (British T.V. channel) a while back about string theory. Now in it there was the question about why gravity was much weaker than the other 3 forces and a possible answer was that the gravity string was either a closed string or an open string (i.e. either a circle or a line) - I can't remember which way round it was and was different from the other forces in that they were of the other sort. Now the upshot of this difference was that gravity leaked from our universe into other universes and hence the reason was a lot weaker.

Well that got me thinking, if that was true then why couldn't gravity leak into our universe from other unoverses and if it did that's what dark matter was?

Of course there's always to chance that I picked up the what was said on the Channel 4 prog. wrongly and what I've said above is total rubbish? If not is it possible