Dark Matter; New Daily Scientific American Podcast, 60-Second Science; Steve Irwin, the "Crocodile Hunter"

Summary: In this episode, MIT astrophysicist Paul Schechter offers some perspective on recent research about the universe's mysterious "dark matter." Journalist Karen Hopkin and host Steve Mirsky talk about the new daily Scientific American podcast, called "60-Second Science." And Scientific American magazine contributing editor Sarah Simpson shares some thoughts about the late Steve Irwin, the "Crocodile Hunter." Plus we'll test your knowledge about some recent science in the news. Websites mentioned on this episode include www.sciam.com, www.sciam.com/podcast, www.sciam.com/news and Paul Schechter's home page, http://tinyurl.com/r9yg6.