|
|
Article: Through a glass, darkly; Cosmology.(Dark matter really does exist)
- Article from:
- The Economist (US)
- Article date:
- August 26, 2006
CopyrightCOPYRIGHT 2006 Economist Newspaper Ltd. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
|
The first proof that dark matter really does exist
THAT the universe is filled with matter people cannot see--matter that simply passes through pretty much everything undetected--is hard to accept. But it would appear to be true. The alternative--that somehow gravity works differently at extremely large distances--has just been ruled out by astronomers who are watching one of the most violent collisions in the history of creation.
Most galaxies are found in gravitationally bound groups, called clusters. Sometimes these clusters collide and merge with one another. The bullet cluster--otherwise known as 1E0657-556--is one such example. Some 100m years ago, ...