According to a theory proposed in 2007, the explosion of a comet over North America killed off the Clovis people and many of the continent’s largest mammals nearly 13,000 years ago. Not so fast, says a new study published in the Proceedings of the National Academy of Sciences, fueling a WWE-style stare down between the opposing camps.
The new report explains that archaeologists have examined sediments at seven Clovis-age sites across the United States, and found that the concentration of magnetic debris was insufficient to confirm an extraterrestrial impact at that time [Nature News]. The original theory’s evidence came from magnetic microspherules, or cosmic debris, discovered in sediments at 25 locations. However, one of the new study’s authors, Todd Surovell, said that even after 18 months of sedimentary analysis and hundreds of hours peering into a microscope, he could find no evidence of microspherules to support the the exploding comet theory. Snap.
But the research team that proposed the comet theory isn’t backing down. “Their study doesn’t negate our hypothesis,” says James Kennett, a palaeoceanographer at the University of California, Santa Barbara… Another co-author, geophysicist Allen West of Prescott, Arizona, says that Surovell’s group didn’t use the correct techniques to extract, identify and quantify the microspherules [Nature News]. Burn.
This isn’t the first challenge to the North American comet theory. A study in February found no evidence of burning biomass that a comet explosion, and the resulting continent-wide fire, would have produced. Kennett, one of the researchers who originally proposed the theory, responded by saying the contradictory studies are “flawed” and published a study in August on his team’s finding of nanometer-sized diamonds, supposedly created during the comet’s impact.
Scientists on both sides of the scuffle have new research scheduled for publication soon, so stay tuned!
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Image: NASA
October 19th, 2009 at 2:47 pm
I would just point out that the research never suggested that an impact ‘killed off the Clovis people.’
The Clovis people didn’t die — their culture morphed into other cultures, probably as a result of the loss of megafauna that they preyed upon.
If there was an impact, it may have killed off the Clovis culture, but not the people.
October 19th, 2009 at 4:05 pm
Mega fauna filled a precariously balanced niche in their envirenment. A comet could have destabilized/ crashed their population much easier than it could mans. Why hasn’t mitochondrial DNA research proved our past here one way or another?
October 19th, 2009 at 6:57 pm
The comet impact may have been far more localized than they imagine :
http://webpages.charter.net/tsiolkovsky/Clovis_Comet_Crater.pdf
http://webpages.charter.net/tsiolkovsky/Darwin's_Valentine.pdf
I arrived at this looking for a terminus for glacial and subglacial lake flooding, the Younger Dryas and Marquette advance, and then the final Laurentide Ice Sheet disintegration. A localized multi-crater impact on the ice sheet at this location at 12,900 BP would have suffered several great flooding events and a glacial readvance, which would have obliterated the evidence and pushed most of the material right down and possibly into Lake Superior.
October 19th, 2009 at 7:41 pm
I’m still trying to figure out how a comet, made of ice, explodes and starts fires.
Melting; yes.
Exploding; possible.
Flammable; I’m not seeing it.
October 20th, 2009 at 12:13 am
A cataclysmic explosion makes the oxygen in our atmosphere into fuel, creating a raging wall of fire that feeds on itself.
Dresden and tokyo in WWII both burned to the ground because of fire storms created by our bombing. Incendiary bombs started fires, but the atmosphere itself fed and fanned the flames. Firestorms killed more Japenese than Fat Man or Little Boy individually. Now picture a rock the size of Gibralter careening into our atmosphere, creating enormous heat as it ploughs through until BOOM, it explodes with the power and heat to mow down all of our hemisphere.
I still think Clovis man killed off the mega fauna his own greedy self though. He was only human..
October 20th, 2009 at 11:28 pm
@TheTraveler: Anything that falls to earth releases energy equivalent to the energy required to put back to wherever it came from. It releases this energy as heat. So, if a comet falls onto earth from interstellar space, then the heat it releases, all in a millisecond, is equivalent to gently putting that thing on the earth and throwing it into interstellar space, all in a millisecond. That’s a lot of heat.
Also, thing moving in interstellar space do so at speed. What I described above was if something fell onto earth from height. If something is travelling at interstellar speeds and smacks into the earth, then much more energy ( heat ) is released.
The fires are started by the heat released.
Picture
October 22nd, 2009 at 1:35 pm
Several of the first peoples remembered these impacts and passed on accounts of them.
There is no reason for them to have made these accounts up unless these impacts did occur.
In my opinion, the only reason there is controversy is the human trait of denial combined with a well funded campaign of denial. The new NASA Inspector General will be in office soon, and hopefully we will then learn about former NASA Administrator Michael Griffin’s failure to respond to the instructions of the Congress in the George Brown Jr. amendment.
The whole affair should make good copy (news stories), just as Keller’s yearly claims that impact did not kill the dinosaurs does. I look for more stories on this “smackdown” over the coming months.
E.P. Grondine
Man and Impact in the Americas
August 25th, 2010 at 8:29 am
A recently completed analysis soon to be published by an independent lab validates the data markers discovered by the Kennent/Firestone/West team. The Surovell group apparently didn’t use the proper techniques in their analysis.
July 22nd, 2011 at 4:02 am
wonderful points altogether, you just gained a new reader. What would you recommend about your post that you made a few days ago? Any positive?