  We explore the complementarity between terrestrial neutrino oscillation
experiments and astrophysical/cosmological measurements in probing the
existence of sterile neutrinos. We find that upcoming accelerator neutrino
experiments will not improve on constraints by the time they are operational,
but that reactor experiments can already probe parameter space beyond the reach
of Planck. We emphasize the tension between cosmological experiments and
reactor antineutrino experiments and enumerate several possibilities for
resolving this tension.
