Hominids

Chapter One DAY ONE FRIDAY, AUGUST 2 148/118/24 The blackness was absolute. Watching over it was Louise Benoit, twenty-eight, a statuesque postdoc from Montreal with a mane of thick brown hair stuffed, as required here, into a hair net. She kept her vigil in a cramped control room, buried two kilometers "a mile an' a quarder," as she sometimes explained for American visitors in an accent that charmed thembeneath the Earth's surface. The control room was next to the deck above the vast, unilluminated cavern housing the Sudbury Neutrino Observatory. Suspended in the center of that cavern was the world's largest acrylic sphere, twelve meters"almost fordy feet"across. The sphere was filled with eleven hundred tonnes of heavy water on loan from Atomic Energy of Canada Limited. Enveloping that transparent globe was a geodesic array of stainless-steel struts, supporting 9,600 photomultiplier tubes, each cupped in a reflective parabola, each aimed in toward the sphere. All of thisthe heavy water, the acrylic globe that contained it, and the enveloping geodesic shellwas housed in a ten-story-tall barrel-shaped cavern, excavated from the surrounding norite rock. And that gargantuan cavern was filled almost to the top with ultrapure regular water. The two kilometers of Canadian shield overhead, Louise knew, protected the heavy water from cosmic rays. And the shell of regular water absorbed the natural background radiation from the small quantities of uranium and thorium in the surrounding rock, preventing that, too, from reaching the heavy water. Indeed, nothing could penetrate into the heavy water except neutrinos, those infinitesimal subatomic particles that were the subject of Louise's research. Trillions of neutrinos passed right through the Earth every second; in fact, a neutrino could travel through a block of lead a light-year thick with only a fifty-percent chance of hitting something. Still, neutrinos poured out of the sun in such vast profusion that collisions did occasionally occurand heavy water was an ideal target for such collisions. The hydrogen nuclei in heavy water each contain a protonthe normal constituent of a hydrogen nucleusplus a neutron, as well. And when a neutrino did chance to hit a neutron, the neutron decayed, releasing a proton of its own, an electron, and a flash of light that could be detected by the photomultiplier tubes. At first, Louise's dark, arching eyebrows did not rise when she heard the neutrino-detection alarm goping, the alarm sounded briefly about a dozen times a day, and although it was normally the most exciting thing to happen down here, it still didn't merit looking up from her copy ofCosmopolitan. But then the alarm sounded again, and yet again, and then it stayed on, a solid, unending electric bleep like a dying man's EKG. Louise got up from her desk and walked over to the detector console. On top of it was a framed picture of Stephen Hawkingnot signed, of course. Hawking had visited the Sudbury Neutrino Observatory for its grand opening a few years ago, in 1998. Louise tapped on the alarm's speaker, in case it was on the fritz, but the keening continued. Paul Kiriyama, a scrawny grad student, dashed into the control room, arriving from elsewhere in the vast, underground facility. Paul was, Louise knew, usually quite flustered around her, but this time he wasn't at a loss for words. "What the heck's going on?" he asked. There was a grid of ninety-eight by ninety-eight LEDs on the detector panel, representing the 9,600 photomultiplier tubes; every one of them was illuminated. "Maybe someone acciSawyer, Robert J. is the author of 'Hominids', published 2003 under ISBN 9780765345004 and ISBN 0765345005.