National Geographic News, Reporting Your World Daily

Thursday, October 28, 2010

Photo: Dark Matter Properties "Measured" for First Time, Study Says


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The Coma Cluster of galaxies, pictured above, contains thousands of galaxies each housing billions of stars.

Studies of this cluster show that the visible mass of the galaxies is 400 times less than the mass needed to explain their gravitational motion. Scientists therefore theorize that the universe contains an as-yet-undetected substance called dark matter.

New calculations from Cambridge University astronomers suggest that dark matter travels at around six miles (nine kilometers) per second and could be as hot as 10,000° C (18,000° F).

Image © O. Lopez-Cruz (INAOEP) et al., AURA, NOAO, NSF