Weighing Neutrinos with Galaxy Surveys

We show that galaxy redshift surveys sensitively probe the neutrino mass, with eV mass neutrinos suppressing power by a factor of 2. The Sloan Digital Sky Survey can potentially detect N nearly degenerate massive neutrino species with mass m_0. 65 (₌h^2/0. 1N) ^0. 80ex{0ex}eV at better than 2 once microwave background experiments measure two other cosmological parameters. Significant overlap exists between this region and that implied by the Liquid Scintillator Neutrino Detector experiment, and even m_0. 01--0. 1eV, as implied by the atmospheric anomaly, can affect cosmological measurements.