Dark Matters

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Our home galaxy, the Milky Way, is big and bright -- a disk of hundreds of billions of stars that spans a hundred thousand light-years.

Yet most of what makes up the Milky Way is invisible. Its "œdark matter" produces no detectable energy, but we know it's there because its gravity pulls at the visible matter around it. Dark matter outweighs the visible stuff by about 10 to 1.

The leading theory for what makes up dark matter says that it consists of "œwimps" -- weakly interacting massive particles. Wimps have never been seen directly, either in nature or in the laboratory. So there's no consensus that they actually exist.

If they do exist, though, there may be a way to find them, as explained by Steve Ritz, the project scientist for a new space telescope:

RITZ: It turns out if these ideas that the dark matter is actually made of massive particles, if those ideas are right, those particles can meet each other, and when they meet each other, their mass can be converted into energy and other particles. And, in fact, one of those outgoing forms of energy are gamma rays.

The new telescope is designed to look for gamma rays, which are the most powerful form of energy. Certain types of gamma rays could come from the violent collisions of particles of dark matter. So a telescope that's designed to look for some of the brightest objects in the universe could solve the mystery of the darkest objects.

More about the telescope tomorrow.

Script by Damond Benningfield, Copyright 2008

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