U physicist stares into the black matter of the universe

Our solar system may be jaywalking across a dark matter highway.

According to Paolo Gondolo, assistant professor of physics, the universe may only be made up of 5 percent visible matter. The rest may be some form of dark matter or energy.

Although dark matter is only a theory, Gondolo is co-author of a study that proposes a method to prove its existence.

The study was published last week in the Physical Review Letters.

Scientists in Italy in 1998 say their instrument, known as DAMA, detected a flow of Weakly Interacting Massive Particles from the Milky Way. WIMPs are a form of dark matter.

The DAMA detector uses special crystals to detect invisible matter flowing to Earth from the universe. Other detectors around the world use a different method and did not detect the WIMPs, calling the DAMA results into question.

WIMPs may flow into Earth from the Milky Way or from a much a galaxy nearby, called Sagittarius.

The WIMPs from Sagittarius form a “highway” of flowing matter speeding at 670,000 mph that the earth sometimes intercepts as it orbits the sun, Gondolo said.

Scientists say the DAMA, which is more sensitive than other instruments around the world, may have been affected by environmental factors in the laboratory, making researchers think it was detecting WIMPs from the Milky Way.

Gondolo and the other authors of the study proposed having the DAMA measure WIMP flow from Sagittarius. The changing proportions of high to low energy in that WIMP flow are too distinct to be duplicated by laboratory environmental factors.

If the crystals in DAMA successfully detect those energy proportion changes, scientists would be willing to concede that it also detected WIMP flow from the Milky Way.

If the instrument does indeed detect WIMPs, that is proof of the existence of dark matter, Gondolo said. The other co-authors of the study are physicist Katherine Freese and graduate student Matthew Lewis of the University of Michigan and astronomer Heidi Jo Newberg of Rensselaer Polytechnic Institute in Troy, N.Y.

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