Dark energy and cosmic sound

I describe how acoustic oscillations imprinted into the late-time correlations of galaxies by baryonic physics at the epoch of recombination can be used as a cosmological standard ruler. Measurements of this length scale by large galaxy surveys would allow us to compute the angular diameter distance to and Hubble parameter at the redshifts of the survey. This in turn offers a robust way to measure the acceleration of the universe. I briefly present calculations of the statistical performance from baseline surveys; full details of the methods and results are available in Seo and Eisenstein [ApJ, 598 (2003) 720]. I discuss the advantages and disadvantages of the acoustic oscillation method relative to other dark energy probes.