One of the biggest unsolved problems currently facing astrophysics is that galaxies and clusters of galaxies rotate faster than one would expect, given the amount present in them baryonic (normal) matter. Such high speeds require a nucleus whose mass is much greater than that which is possible, if it consisted of stars, dust, and other baryonic objects. This has forced scientists to propose the theory that galaxies located in the center core of non-baryonic particles - dark matter. One of the scientists skeptical about dark matter, CERN physicist Dragan Slavkov Hadzhukevich, has suggested that the illusion of dark matter could be caused by the gravitational polarization of the quantum vacuum.
"One school professes the existence of dark matter, and the other proposes to modify the law of gravity," - he said. "I propose to go the third way, without dark matter and the change in the law of gravity."
If matter and antimatter gravitationally repel each other, it means that the virtual particle-antiparticle, emerging and disappearing in the quantum vacuum, are "gravitational dipoles" (having two poles). That is, each pair forms a system in which a virtual particle is positively charged, while the other - has a negative charge gravity. Under this scenario, the quantum vacuum will consist of a set of virtual gravitational dipoles, taking the form of dipolar fluid.
"We can not imagine our universe as a union of two interacting elements," - said Hadzhukevich.
He explained that the virtual gravitational dipoles in the quantum vacuum may be baryonic matter gravitationally polarized nearby massive stars and galaxies. When all virtual dipoles are arranged in one direction, it generates additional gravitational field, in addition to the gravitational field of stars and galaxies. Thus, polarized quantum vacuum can produce the same effect, "increase speed" galactic rotation as a hypothetical dark matter or modified law of gravity.