The Reality of Dark Matter - Proven by Chandra?
Dark matter's murky nature has always sat a bit uneasily with astronomers.
"It is uncomfortable for a scientist to have to invoke something invisible and undetectable to account for 90 percent of the matter in the universe," said Maxim Markevitch, a Chandra astrophysicist and researcher with the study.
http://www.nasa.gov/vision/universe/starsgalaxies/dark_matter_proven.html