Ice Age Extinctions (broadcast Friday, September 28th, 2007)

A colorized scanning electron microscope image of a glassy carbon sphere about .012 inches in width that may contain evidence of extraterrestrial impact. SEM imaging by Jim Wittke

One team of scientists thinks it knows what killed the woolly mammoth and other ice-age creatures. In a paper published this week in the Proceedings of the National Academy of Sciences, they say they have evidence that a comet or other low-density space object exploded in the upper atmosphere of the Earth about 13,000 years ago, possibly leading to the extinction of mammoths and the decline of Stone Age people. We'll talk about their findings.