At 7:20 a.m., on a hilltop overlooking the wooded highlands in Minnesota’s Iron Range, a dozen men and women emerge from parked cars, some wide awake in flannel and Carhartt, some weary in khakis and button-down shirts. A few discuss the Wild and the politics in nearby Ely; others trouble over germanium crystals and liquid nitrogen. Nobody bothers to look to the left, at the random assortment of old mining buildings and the pastoral view over the town of Soudan just beyond. Nor do they look up at the twenty-five-foot tall elevator frame, whistling in the soft breeze, nor down the black mine shaft that it straddles. This is all just part of getting to work on an average Monday morning.
Bill Miller, the stout, bearded manager of the Soudan Underground Laboratory, steps out of an orange Toyota Sienna station wagon. He walks with authority, but in an easy loping manner that suggests he never flaunts it. He slides open the door to a four-by-six-foot, two-story iron elevator car suspended over the mine shaft. The assembled group crowds into the space, shoes and boots scraping across a grimy metal floor.
Conversation continues, even as the door is slammed shut and the light is reduced to a pale glow through a dirty window. Then, promptly at 7:30, the car lurches down into a quick, absolute blackness that smears before the eyes and stops conversations in mid-sentence. The car shakes aggressively, almost enough to require handholds, as on a subway car. There is a brief flash of light from a bulb passed in the dark descent, then more darkness, more vibrations. The grinding and speed seem to increase. Another flash of light, then more darkness.
The noise stops abruptly, yet the car continues in relative silence, as if cut loose. A new, rotten light oozes through the window, illuminating long strips of concrete. After three interminable minutes, during which nobody speaks a word, the car slows and bounces to a stop. The daily commute is complete. A dirty face topped by a hard hat appears in the glass and the door slides open into a musty rock cavern run through by railroad tracks. Interrupted conversations start up again. A steel sign greets the passengers as they exit:
“LEVEL NO. 27—2341 FEET BELOW THE SURFACE—889 FEET BELOW SEA LEVEL.”
Miller turns right, leading the way into a four-and-a-half-story cavern where a device known as the “Far Detector” looms. Its 486 octagonal steel plates hang like ghostly blue and green file folders from a one-hundred-foot-long steel infrastructure. Each plate is twenty-seven feet in diameter, one inch thick, and punctured by a tree-trunk-sized, flesh-colored coil of wires and cooling hoses, which drops like a horse’s tail onto the cavern floor. Three stories of walkways run the length of the detector, providing access to cables that run in rainbow arcs from each plate to racks of monitors. The device has no moving parts and emits no sound, yet the cavern is filled with a low, constant hum not unlike the sound of blood flow magnified by a stethoscope. “Ventilation system,” Miller says by way of explanation. “Bats sometimes get stuck in it.”
In early 2005, the Far Detector will become the target for a beam of subatomic particles called neutrinos, fired through the earth from Fermilab, a particle accelerator five hundred miles to the south, on the outskirts of metropolitan Chicago. After a while, and nobody can say exactly how long it will take, enough neutrinos will be captured in the far detector’s six thousand kilotons of steel to allow physicists to determine whether, in fact, they change—or oscillate—in transit. This entire process is known as the Main Injector Neutrino Oscillation Search (MINOS), a grand experiment whose startup costs—including the far detector in Soudan, a smaller “Near Detector” at Fermilab, and the neutrino beam—run to more than $170 million in federal funding, with ongoing costs of about $1.4 million per year. In truth, it’s a modest sum for big physics, a fraction of the cost of several other national projects. But outcome, however, is of an entirely different order of magnitude: If MINOS works as planned, the results could fundamentally change our understanding of the universe.