I looked at NASA's website.They published a paper last month in the Astrophysical Journal (available online),from the Marshall Space Flight Center's CHANDRA X-ray Observatory satellite mission.They're looking at dark matter in a galaxy called Markarian 1216.
From the main NASA JPL website,it looks like they're toying around with three possible theories to explain the accelerating expansion of the universe.
It's 'quarky' stuff!