Death from above: The pros… and the cons

Buckle up, Willy: A nice illustration of a mammoth, ruined by a bullseye,
Courtesy rpongsajMan, life 35,000 years ago was so much cooler. Sure, they didn’t have the robots and flying cars we enjoy today, in the future, but think about all the great stuff that was around then… There were mile-high ice cubes roaming the northern hemisphere, hilarious cave men, and practically every animal was huge and had “wooly” attached to its name.

Now we can add to that list “earth-sighted extra-terrestrial mega-shotguns.” This is a scientific term, which I have just invented.

An earth-sighted extra-terrestrial mega-shotgun is, in layman’s terms, a meteorite that explodes in Earth’s atmosphere and blasts the surface with tiny fragments of rock. Scientists have just recently revealed details of a study that suggests that ice-age animals were exposed to an earth-sighted extra-terrestrial mega-shotgun at least once, between 35,000 and 13,000 years ago.

The discovery came as scientists at the Lawrence Berkeley National Laboratory were pursuing the theory that there was an atmospheric impact around 13,000 years ago. The researchers had found layers of sediment across North America, dating to 13,000 BP, which contain trace amounts of meteorite material, as well as a black layer that may be charcoal from wildfires caused by such an impact. The team assumed, then, that animals living at this time might also display evidence of the event. By sorting through the collection of a fossil trading company, the scientists quickly found a large handful of fossils that did indeed appear to be blasted by meteorite fragments.

The majority of the fossils were Alaskan mammoth tusks, each peppered with 2 – 3 mm wide holes with all the characteristics of high-velocity projectile impacts. The material inside the holes was magnetic, with a high iron-nickel content, and depleted in titanium (suggesting an extra-terrestrial origin). The group also found a Siberian bison skull that had been blasted by meteorite shards, which showed healing over the impact holes (implying that the animal survived the event). The meteorite shards appear to have exploded inside the tusk and bone. That’s pretty cool too.

The odd thing, however, is that these ESETMS (Earth-Sighted Extra-Terres… whatever) fossils all appear to be much older than 13,000 years, each dating to around 35,000 BP. This could imply multiple ESETMS impacts, although the authors of the report are attempting to tie the fossils and the sediment evidence into a single event. It is possible, they argue, that the mammoth tusks could have been blasted long after then animals’ deaths, while emerging from permafrost or exposed on a riverbank. This doesn’t account for the healing of the bison skull (unless it dates from a different period than the tusks), nor does it resolve the wide geographical separation of fossils (Alaska and Siberia are close, but not that close). The article doesn’t bring it up, but I wonder if animal migration might explain the distance between the fossils, especially if the mammoths were killed by the meteorites either (their tusks wouldn’t have healed either way, after all).

Aside from what spectacular fun the mega space shotgun would have been, the theory is interesting in that, depending on the date or dates of the events, it may have played a role in the extinction of ice age mega fauna. The cause of the Pleistocene extinctions (which wiped out mammoths, mastodons, giant sloth, etc) has long been under debate – some argue that climate change was the culprit, some believe that increasingly skilled human hunters were responsible, and others think that a combination of the two is most likely. While these meteorite impacts probably wouldn’t have caused the extinction on their own, as one scientist put it, “You can't imagine it helped the animals having a large meteorite hit the Earth's atmosphere and pellet them with shot.”

Help them survive, no. Help them be even more awesome? Yes.