The Origins of the Universe

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The nuclear phase diagram: RHIC sits in the energy Image courtesy of Brookhaven National Laboratory

The nuclear phase diagram: RHIC sits in the energy "sweet spot" for exploring the transition between ordinary matter made of hadrons and the early universe matter known as quark-gluon plasma.

A long time ago in a galaxy far, far away…

Actually, there is no reason either to go to your local theatre or to leave this galaxy for another one far away if you want to know what happened a long time ago in our universe. You can travel back in time and space to the microseconds following the Big Bang, with the answers found by DOE nuclear physicists working at our National Laboratories and universities.

The Big Bang

Everything we know in the universe – planets, people, stars, galaxies, gravity, matter and antimatter, energy and dark energy – all date from the cataclysmic Big Bang. While it was over in fractions of a second, a region of space the size of a single proton vastly expanded to form the beginnings of our universe.

Understanding what happened in the first few microseconds is crucial to knowing how the universe came to look and behave as it does today. And our understanding is increasingly shaped by re-creating the very events that constituted the Big Bang and by studying the primordial soup of fundamental particles of the very early universe. One of the best science tools for this is the Relativistic Heavy Ion Collider (RHIC), a DOE Office of Science User Facility at Brookhaven National Laboratory. At RHIC, over a thousand scientists from all over the world come to study the behaviors of matter as it is thought to have acted microseconds after the Big Bang.

RHIC is a particle collider, and the first such machine capable of mashing together heavy ions, which are atoms that have had their outer cloud of electrons removed. Think of RHIC as a 2.4-mile-long "jousting arena," where ion beams start at opposite ends and travel toward one another at nearly the speed of light. But rather than a knight getting "un-horsed," this high-speed collision melts the protons and neutrons of the ions, freeing the quarks and other particles to disperse in an explosion very like that of the Big Bang.

As the first matter began to emerge from the Big Bang, it went through a number of phases much as steam condenses to water and eventually freezes as it cools – except rather than water, you get the first recognizable matter in the universe – a hot soup of quarks and gluons. Though the whole process occurred within fractions of a second, there were still phases of matter within that process that scientists don't understand. RHIC was initially the only machine in the world capable of re-creating the environmental conditions and temperature adjustments in which matter can rapidly change forms, just like in the microseconds following the Big Bang.

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Brookhaven Lab physicist, Paul Sorensen, stands in front of the massive STAR detector at the Relativistic Heavy Ion Collider.Photo courtesy of Brookhaven National Laboratory

Brookhaven Lab physicist, Paul Sorensen, stands in front of the massive STAR detector at the Relativistic Heavy Ion Collider.

Inside RHIC, ordinary matter tends to melt into its fundamental constituents, with temperatures more than 100,000 times hotter than the center of the sun. This reaction allows scientists to understand the nature of matter and how we all came to be.

"RHIC researchers are able to see the forms of matter that come from the quarks and gluons behaving in a variety of conditions," said Paul Sorensen, a physicist at RHIC. "For example, think of the heavy ion as an onion, but after reacting in these conditions, the onion becomes a bowl of French onion soup."

In addition to RHIC, the Office of Science supports research on the environmental conditions of the Big Bang at the Large Hadron Collider (LHC), located at CERN, the European Organization for Nuclear Research, in Switzerland. LHC permits study of these phenomena under somewhat different temperature conditions from those at RHIC, bringing this matter back to its primordial constituencies. Basically, LHC can turn French onion soup from hot to scalding. By using colliders, scientists are able to break apart particles of matter that were once confined together. This explosive reaction, which separates matter into its primordial elements, is the best way for us to understand the properties of matter.

The findings at RHIC and LHC have taught us a lot about what we are made of and where we came from (and how the universe makes French onion soup!). And though we now know more about the particles of matter that make up our universe, as well as the many different types of matter created by our universe, I look forward to learning "what matters" next.

The Office of Science is the single largest supporter of basic energy research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information please visit

Ethan Alpern is a Communications Specialist in the Office of Science,