Dark Matter Clouds Pinpointed in an Ancient Galaxy Cluster

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The ghostly blue clouds in the center of the Abell 1689 galaxy cluster show where Dan Coe and his team think dark matter is hiding. Abell 1689 is home to about 1,000 galaxies and trillions of stars.


Astronomer Dan Coe studies dark matter at the Space Telescope Science Institute in Baltimore, Md. He recently led a study of a galaxy cluster called Abell 1689. Both the visible galaxies and dark matter add to the gravitational pull in a cluster. These gravitational forces act like a lens, and when light passes through a cluster like Abell 1689, it bends. (Think of how light changes when it passes through an empty glass or a pool of water.) By studying these bending light rays, Coe and his team created a map of Abell 1689 that shows where the dark matter might be hiding in the cluster.

Accepting the existence of dark matter would solve many apparent problems related to the study of the universe.

But a major problem remains: Scientists have been unable to find the actual particles that make up dark matter. Researchers have ideas and they can design experiments to test those ideas. But so far, the hunt for dark matter particles has been a process of elimination.  Experiments have only been able to rule out possible candidates, not find them.

“They’re very elusive,” concedes astronomer Wendy Freedman, director of the Observatories of the Carnegie Institution in Pasadena, Calif. “Astronomers hope [dark matter particles] will be discovered in the next decade.”

The Daily Galaxy via http://www.sciencenews.org sciencenews.org

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Credit: NASA, ESA, and Dan Coe (NASA JPL/Caltech and STScI)

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