Satellite galaxies provide new clues about dark matter

A new study shows that dark matter is about 1000 times less likely to bump into regular matter than previously expected.

From Symmetry magazine:
Scientists have narrowed down how strongly dark matter particles might interact with normal matter.
A team led by scientists from the US Department of Energy’s SLAC National Accelerator Laboratory and Stanford University found that, based on the number and distribution of small satellite galaxies seen orbiting our Milky Way, this interaction is at least a thousand times weaker than the strongest interaction allowed by previous astrophysical analyses.
“Improving our understanding of these interactions is important because it’s one of the factors that helps us determine what dark matter can and cannot be,” says Risa Wechsler, director of the SLAC/Stanford Kavli Institute for Particle Astrophysics and Cosmology and the study’s senior author.

Read full article here.