As far as we know the universe is expanding at a greater rate as time progresses. Some scientists attribute this to dark matter but I'm starting to think of the possibility of gravity. Not gravity from our universe but some other mass outside our universe. I view our universe like a nucleus being split apart (big bang). Gravity from surrounding nucleus (other very dense universes) our attracting the sub particles (galaxies) which could explain the expansion.

Any thoughts would be greatly appreciated,
Sebastien