Do the Milky Way's companions spell trouble for dark matter?

Astronomers from the University of Bonn in Germany have discovered a vast structure of satellite galaxies and clusters of stars surrounding our Galaxy, stretching out across a million light years. The work challenges the existence of dark matter, part of the standard model for the evolution of the universe. PhD student and lead author Marcel Pawlowski reports the team’s findings in a paper in the journal Monthly Notices of the Royal Astronomical Society.