122: How to make a comet with Dr. Michel

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.