in the sky with diamonds …Last year a 26-member team from 16 institutions proposed that a cosmic impact event, possibly by multiple airbursts of comets, set off a 1,300-year-long cold spell known as the Younger Dryas, fragmented the prehistoric Clovis culture and led to the extinction of a large range of animals, including mammoths, across North America. The team’s paper was published in the Oct. 9, 2007, issue of the Proceedings of the National Academy of Sciences…