| Well one of the competitor for "anti-gravity" is dark energy , wich is the energy contained in the vacuum. This energy is supposed to act as the Einstein cosmological constant.Some sort of repulsive gravity. There is many hypothesis about this energy and we don't know too much on it. Some version of the brane theory have tried to explian this by installing the universe in a higher dimensionnal frame in a way analog to a membrane in 3D . each bran in this frame share gravity with the other. The brane could also bent on it self in the higher dimensions , with each fold interacting with thier close folds. Gravitron , in string theory, would be represented by a string closed on itself, and would not be embedded in any space frame, hence they could travel from brane to brane or folds to folds in the higher dimensional frame.Resulting in this effect of "anti-gravity". But that is quite speculative... |