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NASA sheds light on dark matter
Written by Gizmo   
Tuesday, 29 August 2006 10:28

There's an interesting story regarding 'dark matter ' over at The Register:

"NASA says it now has the first direct evidence for the existence of dark matter, thanks to observations of a huge, intergalactic collision.

Researchers using the Chandra-X telescope have been watching two galactic clusters collide, an event they say is the most energetic in the universe, ever, apart from the Big Bang.

They also used Hubble, the European Southern Observatory's Very Large Telescope and the Magellan optical telescopes to track the location of the mass in each cluster using gravitational lensing. This is the phenomenon whereby a sufficiently large mass can actually bend the path of light, so that you can see something that would otherwise be obscured by a massive galaxy, for instance.

As the two galaxy clusters smash into one another, the huge clouds of hot, gaseous normal matter encounter drag, similar to air resistance. Because of this, normal matter is slowed down by the impact of one cluster on another. Dark matter, on the other hand, continues unimpeded since it doesn't interact with normal matter, except through gravity."

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