Is the Cosmological Constant Non-Zero?

There is a discussion of the temperature anisotropy of the cosmic background radiation and of how the first Doppler peak depends on the different contributions to the vacuum energy density. An analytic calculation agrees well with numerical studies and shows that the l-value of the peak depends almost entirely on the geometry of the geodesics since recombination, and not sensitively on the details of the photon-baryon accoustic waves prior to the last scattering. This, and supernovae observations, suggest the cosmological constant is not zero.