Is Gravity Capable of Repulsive Forces?

[Yohan_Borga]

Greetings,

When I was still in college, a professor commented that it was possible that gravity was not a force. He based this on the observation that gravity didn’t seem to have opposite charges. The force of electricity has positive and negative. Gravity does not seem to have such attractive and repulsive properties.
In shashdot, a story titled “Missing Matter… Still Missing” has appeared. It seems that the latest attempt to locate dark matter failed. This doesn’t surprise me because I’ve always had a problem with the theory of “dark” matter and energy. It just doesn’t seem right.
I am wondering if what we observe in cosmology could be the result of gravity’s “opposite” charge of repulsion. Could the vast voids and expansion be accounted for by the repulsive charge of gravity? I’m not a physicist or cosmologist but I am hoping the learned community may speculate on this possibility. How about it folks?

 

[selfAdjoint]

Whatever is causing the accelerated expansion of the universe does act somewhat like gravitic repulsion, but it is not associated with matter, but rather distributed through empty space. This would make problems for a theory of an "opposite charged graviton" I think.

 

[Yohan_Borga]

Whatever is causing the accelerated expansion of the universe does act somewhat like gravitic repulsion, but it is not associated with matter, but rather distributed through empty space. This would make problems for a theory of an "opposite charged graviton" I think.

If opposite charged gravitons exist, how would matter come together?