Re: In the News: Astronomers offer proof of 'dark matter'

Jason Spaceman wrote:
From the article:
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MATT CRENSON
Associated Press

NEW YORK - Astronomers say they have found the best evidence to date
for "dark matter," that mysterious invisible substance that is
believed to account for the bulk of the universe's mass.

Using a host of telescopes, researchers focused on the collision
between two galactic clusters. They found that most of the
gravitational pull from the aftermath of the encounter comes from a
relatively empty looking patch of sky, a strong suggestion that there
is something more there than meets the eye.

"This provides the first direct proof that dark matter must exist,"
said Doug Clowe, a research astronomer at the University of Arizona.

Clowe and his colleagues used NASA's Chandra X-ray observatory, the
Hubble Space Telescope and several ground-based observatories to
examine the "bullet cluster," a clump of galaxies that formed over the
last 100 million years from the violent collision of two smaller
galactic clusters. The object gets its name from a bullet-shaped cloud
of superhot gas on one of its sides.

Most of the visible mass in the bullet cluster is concentrated in that
cloud and another near it. But using a technique known as
gravitational lensing, Clowe and his colleagues show that the force of
gravity is actually stronger in a part of the cluster that appears to
be emptier.

They will publish their results in a future issue of Astrophysical
Journal Letters.
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Read it at
http://www.siliconvalley.com/mld/siliconvalley/news/15327391.htm













J. Spaceman

The following article contains more information on the discovery.
Pretty exciting stuff..
http://www.nasa.gov/home/hqnews/2006/aug/HQ_06297_CHANDRA_Dark_Matter.html

I would just like to propose a toast. Here's to Mr. Ockham and his
razor! Thank you for always betting on the simplest solution. Physics
doesn't have to change to accommodate gravity on galactic scales after
all. Cheers!

.

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