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The timeline below accompanies this main story: Sterile neutrinos leave ghostly fingerprints on cosmos

↑ 1985: Observations of how radioactive tritium decays show hints of a

↓ 1991 – 1993: Experiments rule out a neutrino of that mass

↑ 1993 – 1998: The Liquid Scintillator Neutrino Detector (LSND) at Los Alamos National Laboratory in New Mexico sees muon antineutrinos morph into electron antineutrinos at a based on previous experiments. An intermediate, sterile antineutrino phase could explain the observations

↓ 2007: The MiniBooNE experiment at Fermilab in Batavia, Illinois,

↑ 2010: MiniBooNE runs an experiment more closely resembling LSND’s setup and . To explain the effect, though, two types of sterile neutrinos are needed

↑ 2011: Physicists in France claim that nuclear reactors are . They say the missing may have morphed into sterile antineutrinos