A First Detection of the Acoustic Oscillation Phase Shift Expected from
  the Cosmic Neutrino Background
  The unimpeded relativistic propagation of cosmological neutrinos prior to
recombination of the baryon-photon plasma alters gravitational potentials and
therefore the details of the time-dependent gravitational driving of acoustic
oscillations. We report here a first detection of the resulting shifts in the
temporal phase of the oscillations, which we infer from their signature in the
Cosmic Microwave Background (CMB) temperature power spectrum.
