AlterNet: Stephen Hawking is no dummy. That much has been established. Yet in 2006, when the acclaimed scientist told an audience of mostly university students and professors in China that he was "very worried about global warming" and that Earth "might end up like Venus, at 250 degrees centigrade and raining sulfuric acid,” the dystopian prediction nevertheless dropped off the cultural radar after a few short weeks. Which, of course, is a sad commentary on the state of our …