Big Bang soup at a trillion degrees

Physicists said on Wednesday they had created a new form of matter resembling the stuff of the universe one-thousandth of a second after its birth.

This matter is called quark-gluon plasma. Physicists believe it is key to understanding the dawn of the universe and the interior of atomic nuclei.

"The matter we have created has properties that have never before been observed,'' said William Zajc of Columbia University, one of hundreds of researchers working on the project at Brookhaven National Laboratory.

Whether this new matter actually qualifies as the long-sought quark-gluon plasma is an issue for debate, but all of the scientists who heard the evidence agreed that what they've seen so far looks good.

Since its birth, the universe has gradually cooled from more than 100 trillion degrees to today's relatively frigid conditions.

As temperatures fell below about a trillion degrees, quarks and gluons went from a free state into the confines of protons and neutrons. By reversing that process, even for only an instant, physicists hope to learn how it occurred.

Similarly, smashing apart gold atoms could shed light on how quarks and gluons arrange themselves inside protons and neutrons, and how those bigger particles in turn form nuclei.

At Wednesday's presentation, the researchers described experiments in which gold atoms were accelerated nearly to the speed of light and then smashed together.

These collisions were so violent that the debris they produced briefly reached temperatures of one trillion degrees centigrade, the hottest and densest conditions ever created in a laboratory.