Tuesday, September 25, 2007

Asteroid Arrival: 2012

According to the Mayan Calender and other prophecies (including Nostradamus, folks).


"Cosmic blast may have killed off megafauna; Scientists say early humans doomed, too" by Colin Nickerson/Boston Globe September 25, 2007

Wooly mammoths, giant sloths, saber-toothed cats, and dozens of other species of megafauna may have become extinct when a disintegrating comet or asteroid exploded over North America with the force of millions of hydrogen bombs, according to research by an international team of scientists.

The blast, which the researchers believe occurred 12,900 years ago, may have also doomed a mysterious early human culture, known as Clovis people, while triggering a planetwide cool-down that wiped out the plant species that sustained many outsize Ice Age beasts, according to research published online yesterday in the Proceedings of the National Academy of Sciences.

Scientists have long speculated that an impact from a comet or asteroid may have wiped out dinosaurs 65 million years ago.

But the notion of an extraterrestrial object wreaking such havoc during human times is a bit unnerving even to researchers.

Peter H. Schultz
, a Brown University planetary geologist who participated in the research, was quoted in a release from the university:

"What is sobering about this theory of ours is that this impact would be so recent. Not so long ago, something may have fallen from the sky and profoundly changed our climate and our culture."

The object, with a girth estimated to be 3 miles, appears to have exploded high above present-day Canada with such fury that detritus was spread from California to Belgium. The height of the blast and the cushioning effect of the ice layers that still covered the region would explain the lack of an immense crater.

Ted Bunch
, professor of geology at Northern Arizona University and a retired NASA researcher who specializes in extraterrestrial impact research, in an interview:

"The comet may have broken up into small pieces as it neared the earth, and these pieces detonated in various places above North America and northern Europe."

The cataclysm occurred at the end of the Pleistocene era, when an array of fantastic mammals and birds - including camels, tapirs, and a condor with a 16-foot wingspan - shared North America with Clovis people, hunter-gatherers known for their distinctive stone spearheads.

, one of the authors of the paper, referring to creatures directly exposed to the blast:

"The detonation may have fried them or the shock wave would have compressed them. Others would have been wiped out in massive fires and floods."

[Oh, man! We are gonna be FRIED or "COMPRESSED", hey!]

Indeed, fossil records of some of the most exotic beasts associated with the era, along with Clovis culture, abruptly disappear with a dark layer of dirt called "black mat." The mat was formed by algae-rich water containing soot and other remnants of burned material, according to the research.

Just beneath the black mat layer, scientists found high concentrations of magnetic grains holding iridium, charcoal, soot, carbon spherules, and "glass-like carbon." Also found were tiny diamonds, known as nanodiamonds, and extraterrestrial helium.

: "Nanodiamonds are formed only by the kind of incredible pressures you'd get from an extraterrestrial object slamming into earth. The other material, especially the helium, also strongly suggests [something] extraterrestrial, [most likely a comet or] low-density, carbon-rich [asteroid.]"

The soot is indicative of immense fires that roared across North America, fanned by "hurricane-force winds," according to the scientists.

The research, led by Richard Firestone of Lawrence Berkeley National Laboratory in California, is likely to fan controversy among scientists. That is partly because it flies in the face of recent research suggesting that North America's big mammals were hunted to extinction by early humans, but mainly because the paper argues that the comet's impact triggered a planetwide big chill, the so-called Younger Dryas cool-down, that lasted 1,000 years.

Jeffrey P. Severinghaus
, a geochemist and expert in prehistoric climatology with the Scripps Institution of Oceanography in California:

"This is fascinating research when it comes to the mass extinctions. They really seem on to something. I can imagine this sort of impact causing a cool-down of five years or 10 years, but 1,000 years - well, I'm skeptical. I don't think they have given good evidence for that."

The research will be the subject of a National Geographic Channel documentary on Oct. 7 at 10 p.m."

[I think I'll watch it!]