Large Hadron Collider Recreates an Ingredient of the Newborn Universe

October 30, 2015 | Sarah Tse

A ball of plasma
Photo credit: Joel Kramer/Flickr (CC BY 2.0)

The successes of the Large Hadron Collider just keep coming. This time, physicists have concocted quark-gluon plasma, the fiery brew of particles created just milliseconds after the Big Bang.

Among all the other jaw-dropping discoveries made using the Large Hadron Collider, physicists have now recreated a miniscule droplet of quark-gluon plasma, the primeval cosmic chowder that filled the universe just a fraction of a second after its creation.

SEE ALSO: LHC Confirms Fundamental Symmetry of Matter and Antimatter

Those first few milliseconds bear little resemblance to cosmic conditions for the overwhelming majority of the universe’s history. The “Quark Epoch,” as it is called by physicists, was an incredibly brief period full of immense change in the physical and chemical composition of space. The quark-gluon plasma that dominated this period is unlike any other type of matter because it’s extraordinarily hot and dense.

Here on Earth, we’re surrounded by relatively cold and loosely-packed matter in the states of solid, liquid, and gas. But in the rest of the universe, matter takes the form of plasma, a state similar to gas except it contains electrically charged particles that are not bound to each other. Quark-gluon plasma takes this anarchy a step further by “deconfining” the fundamental bits of matter (quarks) from gluons — the carriers of interactive forces that “glue” quarks together.

When they are separated from their normal configurations in protons and neutrons, quarks and gluons are free to interact with each other and can flow almost without friction. They behave like a continuous liquid rather than like individual particles within a gas. Astronomers believe this wild, scalding soup of tiny particles made it possible for the early universe to undergo so much transformation in just a few seconds.

Of course, actually creating this special type of plasma is an entirely different beast than merely theorizing about its existence. But the powers of the LHC know no bounds, and the physicists working there have managed to create a drop of quark-gluon plasma using unexpected methods. They had been observing collisions between the nuclei of heavy lead ions without intending to study the properties of quark-gluon plasma. Quite by accident, the physicists discovered that a collision between a proton and a lead nucleus was able to produce about a thousand particles of quark-gluon plasma.

Since a proton is so much smaller than a lead nucleus, it can only knock off and fragmentize a minute portion of the nucleus. Physicists hadn’t thought it possible to create a liquid from such a tiny collision, but they discovered that the resulting plasma demonstrated all the fluid-like characteristics of a quark-gluon blend. At 4 trillion degrees Celsius (7 trillion degrees Fahrenheit), this is the hottest liquid physicists have ever created in a lab, as well as the littlest amount.

Studying this plasma will yield many more discoveries about the true nature of such exotic forms of matter. We can also figure out the necessary conditions for creating other types of particles, and most importantly, how these substances shaped the early moments of the universe.

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