Astronomer Robert Kirshner: Supernovas, Dark Energy and The Fate of the Universe

Astronomer Robert Kirshner is an expert in supernovae – those spectacular exploding stars that can outshine a galaxy. It's a specialty he chanced on in grad school, and his timing was perfect. The field was really taking off, and it was supernovae that would lead to the biggest cosmological surprise of the last 20 years: the revelation that mysterious "dark energy" os pushing the universe apart at faster and faster rates. Bob and I talked about his career, the discovery of dark energy and what it might mean for the future of the cosmos.