Brian Greene in The New York Times:
THREE hundred feet below the outskirts of Geneva lies part of a 17-mile-long tubular track, circling its way across the French border and back again, whose interior is so pristine and whose nearly 10,000 surrounding magnets so frigid, that it’s one of the emptiest and coldest regions of space in the solar system. The track is part of the Large Hadron Collider, a technological marvel built by physicists and engineers, and described alternatively as heralding the next revolution in our understanding of the universe or, less felicitously, as a doomsday machine that may destroy the planet.
After more than a decade of development and construction, involving thousands of scientists from dozens of countries at a cost of some $8 billion, the “on” switch for the collider was thrown this week. So what we can expect? The collider’s workings are straightforward: at full power, trillions of protons will be injected into the otherwise empty track and set racing in opposite directions at speeds exceeding 99.999999 percent of the speed of light — fast enough so that every second the protons will cycle the entire track more than 11,000 times and engage in more than half a billion head-on collisions.
The raison d’être for creating this microscopic maelstrom derives from Einstein’s famous formula, E = mc2, which declares that much like euros and dollars, energy (“E”) and matter or mass (“m”) are convertible currencies (with “c” — the speed of light — specifying the fixed conversion rate). By accelerating the protons to fantastically high speeds, their collisions provide a momentary reservoir of tremendous energy, which can then quickly convert to a broad spectrum of other particles. It is through such energy-matter conversion that physicists hope to create particles that would have been commonplace just after the big bang, but which for the most part have long since disintegrated. Here’s a brief roundup of the sort of long-lost particles the collisions might produce and the mysteries they may help unravel.