Scientific American editor Davide Castelvecchi reports from the annual meeting of the American Geophysical Union (AGU) in San Francisco. Subjects include the extinction of the dinosaurs and the Orbiting Carbon Observatory. And CNET Senior Associate Editor Michelle Thatcher gives us the lowdown on netbooks and tablet PCs. Plus, we'll test your knowledge about some recent science in the news. Web sites related to this episode include www.agu.org; crave.cnet.com