Stars & Astronomy

Shadow Universe

December 4, 2008 on 11:54 pm | In Astronomy | No Comments

A concatenation of puzzling results from an alphabet soup of satellites and experiments has led a growing number of astronomers and physicists to suspect that they are getting signals from a shadow universe of dark matter that makes up a quarter of creation but has eluded direct detection until now.

Physicists caution that there could still be a relatively simple astronomical explanation for the recent observations. But the nature of this dark matter is one of the burning issues of science. Identifying it would point the way to a deeper understanding of the laws of nature and the Einsteinian dream of a unified theory of physics.

On Thursday, a team of astrophysicists working on one of the experiments reported in the journal Nature that a cosmic ray detector onboard a balloon flying around the South Pole had recorded an excess number of high-energy electrons and their antimatter opposites, positrons, sailing through local space.

The particles, they conceded, could have been created by a previously undiscovered pulsar, the magnetized spinning remnant of a supernova explosion, blasting nearby space with electric and magnetic fields. But, they say, a better and more enticing explanation for the excess is that the particles are being spit out of the fireballs created by dark matter particles colliding and annihilating one another in space.

The stakes for dark matter go beyond cosmology. The most favored candidates for its identity come from a theory called supersymmetry, which unifies three of the four known forces of nature mathematically and posits the existence of a realm of as-yet-undiscovered particles.