Abstract

Supernovae have been developed into a powerful tool for cosmological distance measurements. In the (recent) past, supernovae showed that we live in an accelerating universe. In the present supernovae are a key element in constraining the properties of dark energy. While the present data are consistent with a cosmological constant, today’s constraints are not very rigorous. As a community, we are beginning to learn where the systematic problems arise in tightening those constraints and improving our knowledge. I’ll review some of the problems we have encountered with dust absorption and I will show some promising developments using observations in the near-infrared that may mitigate these difficulties. The future will not be as easy as the past, but the conclusion of programs like ESSENCE , Supernova Legacy Survey and the Sloan Supernova Survey plus the Palomar Transient Factory, Pan-STARRS, the Dark Energy Survey, and WFIRST all promise real progress in the years ahead.