Originally published 10/03/2013
Searching for spearheads in the Rio Grande Rift Valley.
Originally published 01/31/2013
Jan. 30, 2013 — Rebutting a speculative hypothesis that comet explosions changed Earth's climate sufficiently to end the Clovis culture in North America about 13,000 years ago, Sandia lead author Mark Boslough and researchers from 14 academic institutions assert that other explanations must be found for the apparent disappearance."There's no plausible mechanism to get airbursts over an entire continent," said Boslough, a physicist. "For this and other reasons, we conclude that the impact hypothesis is, unfortunately, bogus."In a December 2012 American Geophysical Union monograph, first available in January, the researchers point out that no appropriately sized impact craters from that time period have been discovered, nor have any unambiguously "shocked" materials been found....