LEAD, S.D. — Nestled nearly 5,000 feet beneath the earth in the gold boom town of Lead, S.D., is a laboratory that could help scientists answer some pretty heavy questions about life, its origins and the universe.

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.

AP Photo/Amber Hunt

Scientist Tom Schut...