Old gold mine to aid in hunt for dark matter
It's hard to spot from the surface. Looking around the rustic town, there are far more nods to its mining past than to its scientific future. But on Wednesday, when part of the Homestake Gold Mine officially became an underground campus, Lead became the place where the elusive stuff called dark matter might finally be detected.
Unimpressed? Consider this: It's sure to earn itself a reference on TV's "The Big Bang Theory."
"This year, 2012, is going to be a very significant year because we get to turn the ... detector on and know very soon whether we have actually found dark matter or not," said Rick Gaitskell, a scientist with Brown University who has worked alongside dozens of scientists over the past few years to move forward with the Large Underground Xenon experiment -- or LUX -- the world's most sensitive dark-matter detector.
For most people, dark matter is a term that made their eyes glaze over in science class. But for Gaitskell and other scientists, it's the mystery meat of existence.
"It's this huge piece of the puzzle that's just missing for us," said Tom Schutt, a scientist with Case Western Reserve University in Cleveland, who was on hand for the unveiling of the lab Wednesday.
Regular matter -- people and planets, for example -- make up about 4 percent of the total mass-energy of the universe. Scientists estimate that dark matter makes up about 25 percent.
Scientists know it exists by its gravitational pull but, unlike regular matter and antimatter, dark matter is undetectable. Gaitskell -- who said he's been "hunting dark matter" for 23 years -- and his colleagues know only that it could explain why the universe isn't made up equally of matter and antimatter. That, in turn, could explain how the world as we know it came to be.
Gaitskell and Schutt were among a handful of scientists Wednesday who greeted Gov. Dennis Daugaard, former Gov. Mike Rounds, philanthropist Denny Sanford and dozens of scientists and journalists who took the 11-minute ride down a shaft that had been used by countless miners for more than a century.
Beneath the earth are 370 miles of tunnels over 7,700 acres. The new lab takes up about 10,000 square feet, leaving plenty of room for expansion. The once-grimy mine has been washed clean and painted white. Concrete paths were poured for easier walking, and clean rooms ensure that the experiments won't be tainted.
Now the site's ideal, said Kevin Lesko, of Lawrence Berkley National Lab, who is the principal investigator for the Sanford Underground Research Facility. Dark matter is too sensitive to detect in normal laboratories, but one so far underground would help shield it from pesky cosmic radiation. Also, the LUX detector is submerged in water, further insulating it.
The unveiling was a long time coming: The mine opened during the Black Hills' gold rush in 1876 and outlasted many counterparts. In the late 1990s, it employed about 1,000 people, but as the value of gold dropped, hundreds of miners gradually lost their jobs. The mine shuttered for good in 2003.
The science community seized on the closure for its lab potential. Gaitskell said he's worked with 70 scientists and 14 institutions over the past four years to make the LUX experiment a reality.
Experiments are set to begin this year, said Bill Harlan, spokesman for the research facility. All told, the site has cost more than $300 million -- a mix of private donations and state and federal funding. Daily operation costs are covered by the U.S. Department of Energy.
About 70 former mine workers now work for the lab. Greg King, a lifelong Lead resident, is one of them. "The whole town was built up around the Homestake," King said. "As the property closed and people left, a lot of employees left. Now, there's a lot of excitement in town. People are very thrilled that the Homestake is once again, albeit not as a mine."
Liz Tiger, who owns a store on Main Street, said the resurrection of the mine represents hope for Lead, a town of about 3,100 residents. Had it not been for Deadwood, Lead's higher-profile neighbor that draws about 2 million tourists a year, the town might have gone under, she said.
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