The cosmic microwave background (CMB) is the oldest light in the universe, coming to us from a shell roughly 46 billion light years away.
We have learned enormous amounts from its measurement and there is much more to learn. In this talk we’ll first review our understanding of the cosmos with an emphasis on the standard model of cosmology and the CMB. We’ll then address two of the exciting open questions: is the current expansion rate of the universe consistent with that inferred from the CMB and how might we find gravitational waves from the Big Bang?