The new $600 million Relativistic Heavy Ion Collider could solve some of science's deepest secrets. It could also accidentally destroy the universe. Who says particle physics has lost its zing?
Ten years in the making, Brookhaven National Laboratory's Relativistic Heavy Ion Collider is the world's most powerful particle accelerator; when the Long Island, New York, facility (www.rhic.bnl.gov) fires up this month, it should vastly increase our understanding of the moments immediately following the Big Bang. That's the good news.
If everything goes right -please - RHIC should work like this: Near-light-speed collisions will smash gold ions into their component protons and neutrons, producing superintense heat that melts the particles into a soup of quarks and gluons. Quarks are the most basic unit of matter; under ordinary conditions, they never exist freely but are bound into larger particles by gluons. In the collider's high-pressure, high-energy conditions, the quarks and gluons form a plasma, known as QGP, believed to have existed at the birth of the universe.
Some scientists - among them Frank Wilczek of the Institute for Advanced Study, in Princeton, New Jersey - have said that, in theory, RHIC could trigger the runaway formation of a poorly understood breed of subatomic particle known as a strangelet, which "eats" all matter it encounters, a chain reaction that would consume everything everywhere. Fortunately, most experts aren't worried. MIT physicist Bob Jaffe says the chances of RHIC-induced Armageddon are "exceedingly rare" bordering on nil, but as he admits, "you never know." With that in mind, this is how the worst case could play out.
GO! Whether the experiment works or anti-works, things begin the same way. Gold ions fired from a powerful tandem Van de Graaff accelerator travel through a particle booster and the alternating gradient synchrotron, which sends the ions through a magnetic switchyard at 99.995 percent of the speed of light. Two ion beams emerge from the switchyard and enter RHIC, traveling in opposite directions around the track. A magnetic field - created by superconducting magnets wrapped in niobium titanium wire carrying a 5,000-amp current - forces the beams to collide inside the monitoring stations, such as STAR.
WHAP! During the collisions, the kinetic energy of the ions (roughly 40 trillion electron volts) is converted into heat, with temperatures reaching 1 trillion degrees Kelvin - almost 1 million times hotter than the core of the sun. The blast melts the protons and neutrons.
EUREKA! The melting releases quarks and gluons that, for a fleeting 10 trillionths of a trillionth of a second, form QGP. As the temperature drops, the plasma coalesces to its original state, but not before RHIC's detectors record its properties and behavior. Each chamber focuses on a different aspect of the collision. STAR, for instance, detects the presence of QGP indirectly, by measuring the production of two- and three-quark bundles called hadrons.
EEK! Here's where things could start to go wrong. All atom smashers produce a mixture of the six flavors of quarks: up and down, charm and strange, top and bottom. Because RHIC will produce more collisions, chances are it will produce more strange quarks. Under normal conditions, these quickly decay to become lower-energy up or down quarks. But in RHIC's ultrahigh-pressure environment, those strange quarks could feasibly remain stable long enough to combine with up and down quarks to form a strangelet. If the strangelet contains more strange quarks than ups or downs, it will have a negative charge.
R.I.P. A negatively charged strangelet would trigger a relentless process of electron-positron pair creation. The strangelet would strip away the electrons of any normal atom it came in contact with and absorb the exposed nucleus. The process would continue until all matter was converted into strangelets.
