Nestled nearly 5,000 feet beneath the Earth in the gold boom town of Lead, South Dakota, is a laboratory that could help scientists answer some pretty heavy questions about life, its origins, and the universe. Today part of the Homestake Gold Mine—opened in 1876 and shuttered in 2003—officially becomes an underground campus, home to the Large Underground Xenon experiment (LUX), the world's most sensitive dark-matter detector.
To date, scientists have never been able to directly observe dark matter, which makes up about 25% of the total mass-energy of the universe; people and planets make up just 4%. So the science community seized on the mine's closure. Dark matter is too sensitive to detect in normal labs, but one so far underground would help shield it from pesky cosmic radiation. Some 70 scientists and 14 institutions have worked together over the past four years to make the LUX experiment a reality, at a cost of more than $300 million. Experiments are set to begin 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," says one scientist.