If Dr Biermann and Dr Kusenko are right about sterile neutrinos forming the bulk of dark matter, that would clear up several puzzles about the universe.
Dr Biermann and Dr Kusenko think that one in particular of these hypothetical particles known as a sterile neutrino will turn out to be the main constituent of dark matter.
But unlike dark energy, there are several ideas about what it might be, and one of them is the subject of a second paper, in Physical Review Letters, by Peter Biermann of the University of Bonn, in Germany, and Alexander Kusenko, of the University of California, Los Angeles.