Repulsive gravity as an alternative to dark energy (Part 1)

When scientists discovered in 1998 that the Universe is expanding at an accelerating rate, the possibility that dark energy could explain the observation was intriguing. But because there has been little progress in figuring out exactly what dark energy is, the idea has since become more of a problem than a solution for some scientists. One physicist, Massimo Villata of the National Institute for Astrophysics (INAF) in Pino Torinese, Italy, describes dark energy as “embarrassing,” saying that the concept is an ad hoc element to standard cosmology and is devoid of any physical meaning. Villata is one of many scientists who are looking for new explanations of the Universe’s accelerating expansion that involve some form of repulsive gravity. In this case, the repulsive gravity could stem from antimatter hiding in voids.