SPACE.COM - A new theory that suggests dark matter is made up of particles that strongly interact with each other via a so-called "dark force." If true, this may finally explain the extreme densities we see in dark matter haloes surrounding galaxies.
The existence of particles called self-interacting dark matter (SIDM) acts as an alternative to cold dark matter theories which suggest the elusive stuff is made up of massive, slow-moving (and thus cold), weakly interacting particles that don’t collide. The problem with those cold dark matter models is that they struggle to explain two puzzles surrounding what are known as dark matter haloes.
"The first is a high-density dark matter halo in a massive elliptical galaxy. The halo was detected through observations of strong gravitational lensing, and its density is so high that it is extremely unlikely in the prevailing cold dark matter theory," Hai-Bo Yu, team leader and a professor of physics and astronomy at the University of California, Riverside, said in a statement.