Dark Matter Galaxy Discovered

Brits have discovered what may be a dark matter galaxy, VIRGOHI21, in the Virgo constellation, using the Lovell Telescope. The discovery was confirmed using the Arecibo Telescope. The galaxy was observed by the radio telescopes, as there are no stars present -- just mass that is rotating like a galaxy. The astronomers that discovered VIRGOHI21 were observing in the radio spectrum to detect hydrogen atoms. What they found was a mass of hydrogen a hundred times that of our Sun -- yet, at the speed that mass was rotating, there should be a lot more mass. Previous objects have been observed but were subsequently found to contain stars, or be the remnant of two colliding galaxies. VIRGOHI21 was observed back in 2000, and it has taken this long for astronomers to study it for other explanations.

Current thinking places dark matter at a 5:1 ratio over ordinary visible matter. There should be more of the universe than we're seeing. Current theories of galaxy formation also predicts a lot more galaxies than we observe. Finding evidence for a dark galaxy is an important discovery in an answering so long, unanswered questions. The verdict is still on whether VIRGOHI21 is a dark galaxy -- but so far, it fits the profile.

BTW, the image on the right -- I found it on the Register. It's an artist impression of the dark galaxy. That took imagination, you've got to admit. ;-)

For related information, see the following:

Is Cold Dark Matter Still a Strong Buy? The Lesson from Galaxy Clusters [PDF]

A Microlensing Search for Cold Molecular Clouds in Virgo [PDF]

The Dark Matter Crisis [PDF]