Density Not Seen Since The Big Bang?

Scientists say they used a particle accelerator to smash the nuclei of gold atoms together to make the highest density of matter ever created in an experiment.

The accelerator, the Relativistic Heavy Ion Collider, smashed the nuclei together at nearly the speed of light, Brookhaven National Laboratory scientists said at a conference Monday. Physicists who studied the debris streaming from the collisions concluded that densities more than 20 times higher than those within the nuclei of ordinary matter had been produced. Temperatures in the compressed matter topped 1 trillion degrees.

The scientists believe that the last time large amounts of matter so dense and so hot existed was a few millionths of a second after the Big Bang, the explosion credited with giving birth to the universe.

Physicists hope the violent collisions will break protons and neutrons into their subcomponents quarks and gluons further revealing the internal structure of nuclei. Although the measurements reported Monday cannot determine whether that goal has been achieved, they strongly suggest that further collisions will bring the so-called "quark-gluon plasma" to light.

"There is some tantalizing evidence, I would say, but I think that we need to get some better statistics," said John Harris, a physicist at Yale University.

The Brookhaven scientists said measurements at the accelerator, if confirmed, indicate they produced matter with a density approaching two times the record announced last year at the CERN particle physics laboratory in Geneva, Switzerland.

The results may shed light on the birth of the universe and the centers of dense and exploding stars, the scientists said.

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