According to their results, which were presented at the American Geophysical Union meeting in Acapulco, Mexico, during the week of June 4, 2006, a comet entered the Earth’s atmosphere and hit the planet at about 1,000 kilometers (600 miles)  per hour. Debris from the fiery comet was spewed across North America, even showing up in Europe. Wildfires spread across North America—killing large numbers of animal species including the Clovis culture.

Characteristics discovered by the researchers indicate that almost all of what is now called North American was on fire. A carbon-rich layer of sediment—probably from the comet—found at numerous Clovis sites in Canada and the United States show that it was deposited within this timeframe about 12,900 years ago.

The scientists also found carbon molecules that contained the isotope helium-3. The isotope is found very commonly throughout the universe, but is found only rarely on the Earth—which indicates that the isotope came from outside of the Earth.

In addition, nanodiamonds (pure micronized diamond crystals that are about five nanometers or smaller in size, where one nanometer equals one billionth of a meter) were found within this sediment layer. Nanodiamonds are found on the Earth from only meteorite deposits and other extraterrestrial type objects.

The researchers have narrowed their search where the comet blew apart (what is called an “airburst”) to Canada; specifically over Ontario and the Hudson Bay region. The scientists have areas of interest that include the Gainey archaeological site in Michigan; Murray Springs, Arizona; Daisy Cave (off the coast of California); Wally’s Beach (in southwestern Alberta); Lake Hind (southwestern Manitoba); the Hudson Bay, the Carolina Bays, and Topper (Allendale County), Georgia.

One site in Belgium—Lommel—is also being looking into for a possible connection. All of these sites are areas that contain carbon layers and comet debris from the 12,900 year-ago timeframe.

Some scientists will probably hesitate to accept these researchers' results because catastrophic impact hypotheses are generally not quickly accepted by the scientific community. Consequently, further scientific studies are necessary to decide whether these conclusions are valid or not.

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