To celebrate Earth Day, Dr. Kate Marvel talks about models of Earth's climate. She compares many models to learn more about the way our climate works, and how it might change in the future. She also offers advice for those of us who may feel overwhelmed by climate change.
Dr. Patrick Michel talks about comet 67P/Churyumov–Gerasimenko, which was visited by the Rosetta spacecraft. This comet's shape was puzzling. It looked like it had survived a collision, but how could a fragile icy comet survive a high-energy impact? A new study by Dr. Michel and his team sheds light on this mystery.