Monday, November 22, 2010

How the universe evolved from a liquid

Scientists working at the world's largest particle smasher – the Large Hadron Collider at CERN near Geneva, in Switzerland – have found that an exotic soup more than 10 trillion degrees Celsius in temperature was created immediately after the birth of the universe.

This sticky, gloopy substance, known as a quark-gluon plasma, behaved like a hot liquid, according to their results.

This provided the perfect environment for the first particles and atoms to form, which later led to the stars and galaxies that surround us today.

The findings have surprised physicists as they contradict the accepted view of what happened in the immediate aftermath of the creation of the universe – that the Big Bang threw out a superheated gas that clumped together to form matter.

"In the very first instances of the universe, it was actually behaving like a very dense liquid," explained Dr David Evans, a particle physicist at the University of Birmingham who is the UK's lead investigator in the experiment.

"These results are telling us about the evolution of the early universe, which inevitably will have had implications for how the universe looks today.

"We have got to do a lot more analysis and put a lot more thought in to understanding this, but it is a really fascinating result."

The results are the first to be released by a multinational group of more than 1,000 researchers who have been working on an experiment with the Large Hadron Collider that began two weeks ago.

They have been using the particle accelerator to smash atoms of lead together inside a detector known as ALICE in a bid to create "mini big bangs" that are thought to mimic the conditions seen in the fractions of seconds after the universe was created.

The tiny fireballs created inside the 17 mile long particle accelerator, which is buried 300ft beneath the Alpine foothills along the Swiss-French border, reached more than 10 trillion degrees centigrade for a fraction of a second.

via How the universe evolved from a liquid - Telegraph.


The liquid is said to exhibit characteristics like nothing else physicists have observed before, and its collective movement is rather like the way a school of fish swims "as one". In fact, physicists' tentative calculations suggest that its extraordinarily low viscosity makes it the most perfect fluid ever created.

The new state of matter was forged in the Relativistic Heavy Ion Collider, situated at the Brookhaven National Laboratory. Colliding the central cores of gold atoms together, head-on at almost the speed of light, the researchers created a fleeting, microscopic version of the Universe a few microseconds after the Big Bang. This included achieving a temperature of several million million degrees (about 150,000 times the temperature at the center of the Sun). They then detected and analyzed the explosive rush of particles that this miniature Big Bang created. Researchers had confidently believed that they would observe something like "steam", made up of free quarks and gluons, but instead the researchers saw evidence of collective movement as the hot matter flowed out of the collision site. This indicated stronger interactions between the particles than expected, leading to the belief that the quark-gluon plasma is similar to a liquid.

This latest development is much more unusual than anyone expected. "No one predicted that it would be a liquid," said Professor John Nelson from the University of Birmingham, who heads the British involvement in the multinational experiment. "This aspect was totally unexpected and will lead to new scientific research regarding the properties of matter at extremes of temperature and density, previously inaccessible in a laboratory."

via Scienceagogo

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