Monday, February 21, 2011

Early universe revealed at 4 trillion degrees

Early universe revealed at 4 trillion degrees

You've probably heard about the $10 billion particle-smashing machine underneath the border between France and Switzerland. To refresh, it's called the Large Hadron Collider, and its mission is to collide matter at unprecedented speeds and energies to figure out what our universe is made of and how it came to be.

In Washington on Sunday, I sat down with Yves Schutz of the European Organization for Nuclear Research (CERN). Schutz is a scientist with ALICE, an experiment designed to examine what the universe was like immediately after it was formed in the Big Bang. He had spoken about the experiment at the American Association for the Advancement of Science annual meeting.

Back in November, ALICE announced its latest results about what matter looked like in that primordial form.

The scientists have come to their current understanding of this early matter by heating particles up to some 4 trillion degrees, perhaps the highest temperature ever achieved in a laboratory setting, but not as hot as it will get eventually for this experiment, Schutz said. This is so hot - about 200,000 times hotter than the core of the sun - that it doesn't really matter if you're talking about Celsius or Fahrenheit anymore, Schutz said.

When water heats up above a mere 212 degrees Fahrenheit, it turns into a gas. But when you heat up this nuclear matter to 4 trillion, it's a liquid, which is a medium of strongly interacting particles. At the same time, while water is viscous - it sticks to surfaces - this primordial soup has nearly no viscosity whatsoever, a phenomenon that has been observed in a similar way in liquid helium.

Like any hot body of matter, it gives off electromagnetic radiation. And it's not visible to the naked eye because (a) it's too small and (b) it's not in the spectrum of visible light.

Also, scientists are inferring these properties of the early universe in the same way that an archaeologist has to figure out the shape of an ancient vase by looking at the remaining pieces. Scientists can only see the consequences of this quark-gluon plasma and must draw conclusions from the ordinary matter that it becomes.

The nuclear matter used here is made of quarks and gluons, which are some of the fundamental building blocks of matter. The heat comes from the collision of particles in the accelerator - but those aren't what become this quark-gluon plasma. In fact, the quarks and gluons get pulled out of pure empty space. Yes, that's really confusing and impossible to imagine, but it's real.

The particle accelerator is restarting after a winter hiatus and will continue to run at 7 TeV in 2011 and 2012, said Felicitas Pauss, head of International Relations at CERN. Then, it will shut down for more than a year to prepare for particle smashing at the unprecedented energy of 14 TeV.

A lot of attention has been paid in the popular science world to the quest for finding a particle called the Higgs boson, which would explain gravity, among other things. But the scientists at the conference said they'd be happier if it's not found.

"There's a host of other things that could be out there," said Thomas LeCompte, physicist at Argonne National Laboratory. The Higgs is the "simplest and elegant" solution to many problems with scientist's current notions of how the world works, but there's no telling what the Large Hadron Collider will find.