For a small fraction of the astronomers and physicists who have studied this problem, the evidence for dark matter has not proven entirely persuasive. To these scientists, dark matter is not the only way that the motions of stars around galaxies could be explained—or even the patterns of galaxies and galaxy clusters found throughout our universe. Rather than postulating one or more new forms of nonluminous matter, they speculate that we may instead have misunderstood the effects of gravity.
