The Princeton University scientists and others in the Borexino Collaboration have detected geoneutrinos at the Gran Sasso National Laboratory of the Italian Institute of Nuclear Physics. The discovery could explain how reactions taking place in the planet's deep interior affect events on the surface. This stainless steel sphere is part of the neutrino detector used in the project, located nearly a mile below the surface of the Gran Sasso mountain about 60 miles outside of Rome.

(Photo: Paolo Lombardi INFN-MI)

This view shows the exterior of the neutrino detector's 59-foot steel sphere. The scientists expect that geoneutrinos will aid them in better identifying what constitutes matter deep within the Earth.

(Photo: LNGS-INFN)