Relativistic Heavy Ion Collider, also called RHIC, is a device that accelerates particles of matter and causes them to collide. The Relativistic Heavy Ion Collider collides large atomic nuclei at higher energies than any other particle accelerator. Collisions at RHIC produce temperatures exceeding 1,800,000,000,000 °F (1,000,000,000,000 °C)—that is, 1.8 trillion degrees Fahrenheit (1 trillion degrees Celsius). Physicists from around the world study the collisions to learn how matter behaves at extremely high temperatures. The United States Department of Energy sponsors RHIC, which is housed at Brookhaven National Laboratory on Long Island, New York.
The Relativistic Heavy Ion Collider consists of 1,740 powerful magnets arranged along a circular path 2.4 miles (3.9 kilometers) in circumference. Engineers made the magnets using superconductors, materials that can conduct electric current without resistance. Working together, the magnets can accelerate protons and nuclei of elements as heavy as gold to speeds 99.995 percent of the speed of light in a vacuum. No particle can travel faster than the speed of light in a vacuum, 186,282 miles (299,792 kilometers) per second. The nuclear matter produced in collisions measures roughly the size of a single nucleus and cannot be observed directly. Instead, four sophisticated detectors observe the particles that the matter gives off.
The main goal of RHIC is to produce and study a previously unknown state of matter called a quark-gluon plasma. Normally, nuclei consist of protons and neutrons, which are composed of smaller particles called quarks and gluons that are bound together. Physicists predict that at extremely high temperatures, normal nuclei dissociate into a mixture of free quarks and gluons not confined to larger particles. Scientists think that such a quark-gluon plasma dominated the universe in the first few millionths of a second following the big bang. The big bang was a cosmic explosion believed to have started the expansion of the universe. Experiments at RHIC can also measure the detailed properties of quarks and gluons while they are bound together in protons.
In 2000, RHIC began colliding gold nuclei. The collisions produced high-temperature nuclear matter that in many ways resembles researchers’ predictions for a quark-gluon plasma.
See also Brookhaven National Laboratory; Gluon; Matter (Quark-gluon plasmas); Particle accelerator (The synchrotron); Quark.
