Was there a Stone Age apocalypse or not?   New Scientist - November 19, 2009
One narrative has it that about 13,000 years ago a comet blasted North America, wiping out the continent's megafauna Ð as well as its early settlers. It's a compelling story, offering a simple explanation to the mystery of why mammoths, mastodons, and Clovis humans vanished. But it's a controversial theory, and new research suggests the impact was far too small to have done any serious damage.

10 Failed Doomsday Prophecies   National Geographic - November 6, 2009