U.S.scientists have produced the hottest temperature ever recorded, setting a new record in the Guinness World Records – 4 trillion degrees Celsius.

When researchers at Brookhaven National Laboratory in Upton, New York, smashed two gold ions together, the collision created a temperature about a quarter of a million degrees hotter than the sun.

According to Paul Sorenson, a physicist at the laboratory, the process was arduous, taking billions of attempts over 10 years.

It involved colliding pairs of gold ions in the lab’s 3.8-kilometre, two-lane Relativistic Heavy Ion Collider (RHIC).

The beams are placed in the collider in such a way that they travel in opposite directions close to the speed of light. The ions then collide at six intersections where the lanes cross.

The collision causes the ions to “melt” into the protons and neutrons that make them up. The protons and neutrons in turn melt into their constituent parts known as quarks and gluons.

“Those are fundamental particles, and we melt the protons and neutrons into those fundamental particles and then measure the temperature of the system that’s created,” Sorenson told CTV News on Friday.

After the collision, the area cools down, producing thousands more particles, which scientists are then able to analyze.

To determine the temperature produced by the collision, the scientists looked at the resulting photons, much in the same way they would determine the temperature of stars by looking at the light they emit, Sorenson said.

Although the lab had been colliding the ions for years, scientists were only able to record the temperature in early 2010.

Guinness World Records subsequently credited RHIC with achieving the Highest Man-Made Temperature.

The colliding process allows scientists to replicate the densities and temperatures of the early universe -- as early as a microsecond after the Big Bang -- thereby providing insights about the fundamental laws of visible matter.

“The most exciting thing is rewinding the clock and then seeing what the universe behaved (like) at fractions of a microsecond after the Big Bang,” Sorenson said.

He added that although “the man-in-the-street application is very difficult to elucidate at this point…fundamental research like this has always through history led to innovations and applications that change the way the man on the street lives.”