The most delicate measurements so far indicate that an individual neutrino weighs less than a millionth what an electron weighs. Baksan is not the only place dedicated to their surreal pursuit.

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The men and women in these photographs, taken by Maxim Babenko last year, share an underground union with scientists scattered around the world in equally deep places: the Sanford Underground Research Facility in the former Homestake gold mine in Lead, S.D.; the Gran Sasso National Laboratory, beneath the mountain of that name in Italy; the Sudbury Neutrino Observatory in Ontario, Canada; the Super-Kamiokande, deep within Mount Ikeno, Japan; and IceCube, an array of detectors buried in ice at the South Pole.

All of them are trying to listen to quantum whispers about the nature of reality.