Herschel infrared telescope studies Dark Matter

The space-borne Herschel infrared telescope, launched by the European Space Agency with NASA participation, is studying galaxy formation in the early universe. It allows astronomers to look back to the first 3 billion years of the universe’s approximately 14 billion year history.

http://www.jpl.nasa.gov/news/news.cfm?release=2011-057

The degree of clustering of these early galaxies is a reflection of the amount of dark matter relative to ordinary matter. The researchers also note that to form large galaxies (such as our Milky Way) that are efficient sites for robust star formation that one needs enough dark matter relative to the ordinary matter in stars and interstellar gas, but not so much that one ends up with many smaller galaxies.