SUPERNOVA MAY HAVE WIPED OUT MAMMOTHS

A supernova may have led to the extinction of the mammoth and other large creatures on Earth 41,000 years ago. Researchers from the Lawrence Berkeley National Laboratory believe that an explosion about 250 light years from Earth coalesced into low-density comet-like objects that rained onto our planet 13,000 years ago.They believe they have found evidence of the supernova's initial shockwave--mammoth tusks peppered with tiny impact craters produced by iron grains traveling about 6,000 miles per second.