The dark matter is concentrated into a web-like distribution of filaments that intersect at dense nodes where great clusters of galaxies are expected to form and become visible. The yellow lines that cross the box represent light rays from those galaxies propagating through the universe. According to the proposal, galactic centers are hotbeds of annihilating dark matter. Knox described the idea as tentative, but if correct, he said, it could overthrow leading theories of physics, which depend on other types of particles serving as dark matter. His research, done in cooperation with researchers at the University of Chicago and the Fermi National Accelerator Laboratory, is set for publication in the journal Physical Review Letters and was written in response to a puzzle that has stymied astrophysicists.
Scientists are certain that the universe is made up mostly of a mysterious, undetected substance.
The way that galaxies rotate and move around each other gravitationally indicates there is much more mass than what is seen and currently identified as stars, galaxies, nebulae and dust clouds. By studying these motions, astronomers have inferred the quantity and distribution of dark matter. The obscure material is thought to float around in large blobs called halos, each of which is centered on a galaxy . But scientists can detect no such concentrations in the real sky using current methods, such as measuring galaxy rotation rates and studying how the gravity of dark matter might bend light from distant galaxies. The explanation, the researchers think, might be that the dark matter destroys itself in annihilation interactions when it becomes too dense.