Strange ripples in space may point to dark matter near merging black holes
A faint ripple from deep space may be offering physicists a new way to look for one of the universe’s biggest missing pieces. Dark matter is thought to make up most of the matter in the cosmos, yet it has never been directly observed. It does not emit, absorb, or reflect light. So far, the clearest signs of it come from gravity. For example, galaxies bend light and move as though they contain far more mass than astronomers can see. Now a team led by physicists at MIT and several European institutions has developed a way to search for possible traces of dark matter in gravitational waves. These are the distortions in space-time produced when massive objects like black holes collide. After testing their method on publicly available data from the LIGO-Virgo-KAGRA network, they found that one known event, called GW190728, may fit the pattern expected if two black holes merged inside a dense cloud of dark matter. This would be rather than in empty space. But it is a new kind of lead. A …
