The Homestake gold mine extends a mile underground in the Black Hills of South Dakota. Its deep shafts had previously been used by physics professors for scientific experiments, and when it closed in 2003 the property was donated to the state in the hope that more advanced work might be conducted in its caverns deep underground—where the overlaying earth shelters equipment from cosmic rays and other signals that can interfere with sensitive tests. There was no money, however, for creating proper physics labs and workspaces in the old mine. In swooped Denny Sanford, a Dakotan and successful medical entrepreneur who has given away more than a billion dollars in his lifetime. He provided a $70 million donation, which loosened up additional funding from state and federal agencies, and the Sanford Underground Research Facility was operating by 2013. The first major collaboration set up in the new lab was a detector of “dark matter,” the theorized but as yet unseen particle that the standard model of physics suggests may make up about a quarter of the cosmos. Another experiment on neutrinos goes live in 2014. The U.S. Department of Energy is now considering settling two more long-term physics investigations in the philanthropically funded lab.
- Sanford Underground Research Facility, luxdarkmatter.org