Dimmer outlook for dark matter

摘要

Though we can't see it, dark matter is supposed to make up 22 per cent of the universe. Now it turns out it might not exist at all. Earlier this year, the discovery of a ring-like astronomical feature, invisible except for the way its gravity distorts background galaxies, was hailed as proof for the existence of dark matter and the death knell for a rival theory known as modified Newtonian dynamics (MOND). Not so, claims the father of MOND. "MOND perfectly explains the ring," says Mordehai Milgrom of the Weizmann Institute of Science in Rehovot, Israel. "In fact, it explains it more naturally than dark matter."