The discovery, announced on Wednesday, is forcing scientists to rethink their ideas about the formation of galaxies. "We didn't expect that this could happen," said Yale University astronomer Pieter van Dokkum, lead author of the research published in the journal Nature. Paradoxically, the discovery of a galaxy without dark matter may actually confirm that the stuff actually exists by contradicting hypotheses advanced by dark matter doubters. Dark matter, which is invisible, is thought to comprise about a quarter of the universe's combined mass and energy and about 80 percent of its total mass, but has not been directly observed. "Dark matter is not something that galaxies can sort of swap in or out of, like it's kind of an optional thing that galaxies sometimes have and sometimes don't," van Dokkum said.

Source: dna March 29, 2018 04:42 UTC