Apocalypse Deferred; December 1999; Scientific American Magazine; by Alpert; 1 Page(s)

It all began in the "Letters to the Editors" section of the July issue of this magazine. In response to a March article about the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory, several readers expressed alarm about the experiments planned for the Upton, N.Y., facility. The newly built accelerator is designed to smash gold ions together at unprecedented energies; researchers hope the high-energy collisions will momentarily reproduce the hot, dense quark-gluon plasma that filled the universe in the first moments after the big bang. Some readers worried, however, that the experiments might also produce a miniature black hole that would sink to the earth's core and devour the whole planet in minutes.

Fears of a man-made apocalypse spread quickly on the Internet and soon appeared as screaming headlines in British newspapers ("Big Bang Machine Could Destroy Earth," the Sunday Times of London warned). Physicists argued that RHIC would not even come close to creating black holes-for that to happen, the ions would have to be compressed to a density 1060 times greater than that produced by the RHIC collisions. But another doomsday scenario was harder to dismiss. Some researchers believe the ion smashups could generate a new form of matter called strangelets. These subatomic bundles would combine three species of quarks: the commonplace "up" and "down" quarks that are the building blocks of protons and neutrons, and the rarer "strange" quarks that are found in short-lived particles such as kaons.