Inflation and the Cosmic Web

[Fortnum]

The rubber-sheet model of gravity pictures gravity as the effect of hollows in space-time due to the mass of an object. If the model included bumps in space-time as well, the effect would be to channel all the mass into the valleys between the bumps forming a network of matter across the sheet. Turning the flat sheet into three dimensions, with space-time in the fourth, we would end up with a foam-like structure of voids surrounded by a 3-D network of matter, very much like the cosmic web. What could cause such bumps in space-time? If mass causes the hollows anti-mass would cause bumps, but can such a concept as anti-mass exist? If it did it might help explain the missing anti-mater from the big bang.

[Bill_K]

Antimatter does not have negative mass. It has positive mass and attracts things just like normal matter. The Tevatron has been colliding protons with antiprotons since it was built in 1983. When an E field is applied, the antiprotons accelerate in the normal way expected for a particle having mass equal to a proton and a negative charge. They circulate in the machine for hours at a time, and have never been observed to "fall up"!

[Arch2008]

This may be a better explanation of the matter/anti-matter imbalance:
http://www.symmetrymagazine.org/breaking/2011/03/30/rare-particle-decays-could-indicate-presence-of-new-physics/