That Comet Theory

From Rex Dalton at Miller-McCune:

It seemed like such an elegant answer to an age-old mystery: the disappearance of what are arguably North America’s first people. A speeding comet nearly 13,000 years ago was the culprit, the theory goes, spraying ice and rocks across the continent, killing the Clovis people and the mammoths they fed on, and plunging the region into a deep chill. The idea so captivated the public that three movies describing the catastrophe were produced.

But now, four years after the purportedly supportive evidence was reported, a host of scientific authorities systematically have made the case that the comet theory is “bogus.” Researchers from multiple scientific fields are calling the theory one of the most misguided ideas in the history of modern archaeology, which begs for an independent review so an accurate record is reflected in the literature.

The comet impact theory was intriguing partly because it depended on so much new science: "carbon spherules" and "nano-diamonds" as evidence of an impact, mathematical modeling of what would happen if a comet hit an ice sheet, and so on. Faced with such a barrage of ideas, many archaeologists reacted as I did, with cautious interest.

Alas, it now seems that many of the "nano-diamonds" are nothing of the kind, that "carbon spherules" are omnipresent in some soils, and the original investigators' dating of their soil sequences was off by a thousand years. Not to mention that one of the authors of the original paper, who signed himself Allen West, is actually Allen Whitt, who was convicted of fraud in 2002 after charging California towns thousands of dollars for bogus water studies. It was this mysterious figure who collected much of the original data, and now his work is pretty much dismissed by everyone involved. Except, as Dalton notes, the other two authors of the original paper. Marine geologist James Kennett and physicist Richard Firestone are sticking to their guns. Maybe they see something nobody else can, but it seems that they have just got their backs up to the wall:

Such intransigence has been seen before in other cases of grand scientific claims. Sometimes those theories were based on data irregularities. Other times, the proponents succumbed to self-delusion. But typically, advocates become so invested in their ideas they can’t publicly acknowledge error. . . . all of these phenomena may be in play, apparently creating a peculiar bond of desperation as the theory comes under increasing attack.

It is very hard to say, "I was wrong."