A sign welcomes visitors to a lab 4,850 feet beneath the earth on Wednesday, May 30, 2012. The Sanford Underground Research Facility in Lead, S.D., will house the world's most sensitive dark-matter ... more 
A sign welcomes visitors to a lab 4,850 feet beneath the earth on Wednesday, May 30, 2012. The Sanford Underground Research Facility in Lead, S.D., will house the world's most sensitive dark-matter detector. Scientists say that the lab _ housed inside the now-shuttered Homestake Gold Mine _ could help scientists understand the origins of the universe. (AP Photo/Amber Hunt) less 
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Associated Press | Photo By Amber Hunt
Wed, May 30, 2012 8:19 PM EDT