Exploring abrupt climate change induced by comets and asteroids during human history

Royal Astronomical Society touts new Napier paper

Napier paper: Palaeolithic extinctions and the Taurid Complex

When the story books are re-written, the increasing — but uncoordinated — coherence between the Brit Neo-Catastrophists and the American YDB team will make interesting study for students of science history.   These two groups have no overlap but the facts are leading them to the same place.  Ditto for the Holocene Impact Working group.


13,000 years ago the Earth was struck by thousands of Tunguska-sized cometary fragments over the course of an hour, leading to a dramatic cooling of the planet, according to astronomer Professor Bill Napier of the Cardiff University Astrobiology Centre. He presents his new model in the journal Monthly Notices of the Royal Astronomical Society.

The cooling, by as much as 8 degrees C, interrupted the warming which was occurring at the end of the last ice age and caused glaciers to readvance. Evidence has been found that this catastrophic change was associated with some extraordinary extraterrestrial event. The boundary is marked by the occurrence of a “black mat” layer a few centimeters thick found at many sites throughout the United States containing high levels of soot indicative of continental-scale wildfires, as well as microscopic hexagonal diamonds (nanodiamonds) which are produced by shocks and are only found in meteorites or impact craters. These findings led to the suggestion that the catastrophic changes of that time were caused by the impact of an asteroid or comet 4 km across on the Laurentide ice sheet, which at that time covered what would become Canada and the northern part of the United States.

The cooling lasted over a thousand years, and its onset coincides with the rapid extinction of 35 genera of North American mammals, as well as the disruption of the Palaeoindian culture. The chief objection to the idea of a big impact is that the odds against the Earth being struck by an asteroid this large only 13,000 years ago are a thousand to one against. And the heat generated by the rising fireball would be limited by the curvature of the horizon and could not explain the continent-wide occurrence of wildfire.

Professor Napier has now come up with an astronomical model which accounts for the major features of the catastrophe without involving such an improbable event. According to his model, the Earth ran into a dense trail of material from a large disintegrating comet. He points out that there is compelling evidence that such a comet entered the inner planetary system between 20,000 and 30,000 years ago and has been fragmenting ever since, giving rise to a number of closely related meteor streams and comoving asteroids known as the Taurid Complex.

In the course of the giant comet’s disintegration, the environment of the interplanetary system would have been hazardous and the Earth would probably have run through at least one dense swarm of cometary material. The new model indicates that such an encounter would last for about an hour during which thousands of impacts would take place over continental dimensions, each releasing the energy of a megaton-class nuclear bomb, generating the extensive wildfires which took place at that time. The nanodiamonds at the extinction boundary would then be explained as having come in with the comet swarm.

One recent meteorite is known which may have come from this giant comet progenitor: the Tagish Lake meteorite, which fell over Yukon Territory in January 2000. It has the highest abundance of nanodiamonds of any meteorite so far analyzed.

Professor Napier sums up his model: “A large comet has been disintegrating in the near-Earth environment for the past 20,000 to 30,000 years, and running into thousands of fragments from this comet is a much more likely event than a single large collision. It gives a convincing match to the major geophysical features at this boundary.

11 Responses

  1. Bill Napier’s paper is a great step forward in understanding how comets can interact with Earth, our precious blue home planet. He has my congratulations for this review and the article in the WSJ recognizing his epochal achievement.

    Beside explaining the YD disaster, there are numerous historical reports of “fire from heaven,” which now may be given greater credence.

    Even the the CFD may have to concede that the 1871 fire was not caused by Mrs O’Leary’s cow kicking over a lantern. There were effects reported of an electrical nature which may have been caused by plasma streams of incoming cometary debris, but this is not considered in Napier’s paper.

  2. Hmmmm….

    1,000 to 1 against?

    Perhaps that its just that NASA’s impact estimates are seriously in error.

    So bad, in fact, as to constitute a menace to the public’s safety and well being.

    (PS – sorry, Hermann, but from what I can make out at the current time, the Great Chicago Fire was not caused by Comet Biela)

  3. Earlier in this site, many questions were in fact raised re: NASA’s very conservative estimates (dare I say unrealistic), as to impact hazard here on planet Earth.

  4. Yes indeed, Rod, there was some discussion here at the Tusk.

    If you watch the TV documentaries, you’ll notice that Don Yeomans of NASA’s NEO office at JPL is the only NASA official with guts enough to explicitly talk about the “comet and asteroid” impact hazard instead of the “asteroid” impact hazard.

  5. Hermann:

    Beside explaining the YD disaster, there are numerous historical reports of “fire from heaven,” which now may be given greater credence.

    It is so not possible for science to credit historical accounts of 13,000 years ago when they don’t even respect accounts from 200 years ago. Even anything before 1900 is treated as myth unless corroborated by something post-1980.

    Modern is everything. Pre-1800 is all ancient mumbo jumbo word-of-mouth obvious silly bedtime stories. 13,000 years ago? I can hear the muffled laughter from here. They could say the Sun came up two days in a row and modern scientists wouldn’t believe it. The arkies would argue that “Sun” meant God, and “up” meant north. And that they sacrificed three virgins and 145 captured enemy warriors.

  6. Hermann –

    True story: In 2001, I was traveling through
    Manistee, Michigan, about halfway up the eastern shore of Lake Michigan. I stopped and had lunch and then chose to take a short boat tour. Along the way the guide related this history —-

    On the same day that Chicago was devastated by the Great Fire, both Peshtigo, Wisconsin and Manistee, Michigan were also destroyed by fire. The guide told how in Manistee it is the general conviction that all three were struck by meteors which started all three conflagrations.

    See also http://tiny.cc/4kzlbw “Could A Meteorite or Comet Cause All The Fires of 1871?” which includes:

    Consider a statement by the Detroit Post on Oct. 10, 1871: “In all parts of the state, as will be noticed by our correspondence during the past few days and also today, there are numerous fires in the wood, in many places approaching so near to towns as to endanger the towns themselves.”

    In Holland, fire destroyed the city, in Lansing flames threatened the agricultural college and in the Thumb, farmers trying to establish homesteads soon would be diving into shallow wells to escape an inferno some newspapers dubbed: “The Fiery Fiend.” Many did not escape.

    Fires threatened Muskegon, South Haven, Grand Rapids, Wayland and reached the outskirts of Big Rapids. A steamship passing the Manitou Islands reported they were on fire.

    And this speculation:

    In the month of the Perseid Meteor shower, it is interesting to ponder – could a disintegrated comet be the cause of the fires?

    Perseids impacting is just as possible as Taurids.

    I am not so sure that both an impactor AND Mrs O’Leary’s cow didn’t both happen. A startled cow with a lantern and an impact are not really hard to believe.

  7. Steve –

    thanks for the same day report from the Detroit Post and your guide’s local historical memories. Maps exist that show the swath of land burnt on both sides of Lake Michigan, trending SW to NE. For possible comets Bob Kobres has facts. It would be nice for a mainline astronomer to review comets, comet fragments, likely orbits, thermal effects, etc.

  8. One or two more points maybe about that 1871 article.

    Some naysayers on the meteor fragments talk about dry forests and all. October 8th tends to not be dry in the upper Midwest. Dryness if anywhere would normally be to the south. Weather reports could be looked up.

    One other bah humbugger talks about meteors landing and being cold, except the surface ablation warms the outer mm or so. This might have been in the article, but it is too late right now. But all the meteors we ever see video of are heated up like mothers, some to the point of exploding.

    Ed or George, can you address that, just for my education? (And save me looking it up?) Thanks if you do.

  9. Hi Steve, Hermann –

    Having visited the Pehstigo Fire Museum, I can tell you that no one there had attributed the fire to meteors or Comet Biela.

    The area was bone dry that year, and there had been numerous smaller fires which had been extinguished. The general concesnsus was that the area was so dry that static electricity would start fires.

    Sparks from friestorms would travel for miles, as from Peshtigo to th4e Door Peninsula.

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