Magnetic senses! Big dinosaurs! Old paint! Inca takeovers! Black Death! Silk age! Restless volcano! Polar maps! And a wondrous universe of abundant carbon atoms! It's your Thursday Science Watch, where we watch science—with gravitas!

Many liberals were upset with Barack Obama for not using Tuesday's Oval Office address to pressure the Senate into passing a cap-and-trade system or carbon tax. But may he have a "secret plan" in the works, as some are suggesting?