New observations and new ideas about cosmic inflation

Proposed 35 years ago, the inflationary hypothesis is one of cosmology's sturdiest ideas and a continuing source of speculation and testing. Inflation inserts into the earliest instant of the big bang a period when space itself expanded exponentially, explaining why different regions of space have temperatures and curvatures that are nearly equal. In recent years there have been attempts to confirm inflation and look for evidence supporting different versions of the theory. Detailed observations of the cosmic microwave background have supported inflation, and several groups of astronomers are taking measurements that could shed additional light. Alan Guth, author of the hypothesis, will reflect on what was learned in last year's excitement over the BICEP-2 team's measurement, what might come from current observations, and how inflation theory is being refined through interaction with theorists proposing that our universe is just one among others. Social media hashtag: #CosmicInflation.