  We show that upcoming CMB satellite experiments and large redshift surveys
can be used together to yield 5% determinations of H_0 and Omega_m, an order of
magnitude improvement over CMB data alone. CMB anisotropies provide the sound
horizon at recombination as a standard ruler. For reasonable baryon fractions,
this scale is imprinted on the galaxy power spectrum as a series of spectral
features. Measuring these features in redshift space determines the Hubble
constant, which in turn yields Omega_m once combined with CMB data. Since the
oscillations in both power spectra are frozen in at recombination, this test is
insensitive to low-redshift cosmology.

Astrophysics