"Our present understanding of the history of the universe says that these temperatures were reached first about a microsecond after the Big Bang. Even higher temperatures were believed to exist earlier," said Steven Vigdor, with the Relativistic Heavy Ion Collider, a 2.4-mile circumference atom smasher at the Department of Energy's Brookhaven National Laboratory.
The experiment is intended to test models simulating the early universe in an attempt to understand how it came into existence and evolved.
The measurement itself was extremely difficult to make, added Barbara Jacak, a physicist with Stony Brook University.
"The plasma only lives for a billionth of a trillionth of a second so we can't stick a thermometer in it," she said.
Instead, scientists use photons of high-energy light to make the measurement.
The experiment also verified the asymmetrical nature of quark-gluon plasma, replicating conditions believed to be responsible for the universe's existence.
"If the universe was symmetrical, the Big Bang would have produced equal amounts of matter and antimatter, which would have annihilated each other, leaving only radiation," said Dmitri Kharzeev, a theorist at Brookhaven. "The universe would be a very desolate place."