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

Journal of Cosmology (Part I): Napier

Crumbling Comet Schwassmann-Wachmann 3 Approaches

Today I added a link to the ‘Great  Link’s on the right sidebar to a fine ET extinction and Younger Dryas Boundary round-robin thrown last year by the Journal of Cosmology.  The Journal solicited a number of distinguished contributers both supportive and dismissive of the idea the earth encountered a game-changing cosmic swarm 13,000 years ago.

These papers make excellent fodder for the Tusk and I will put up a several of them in the next few weeks.  I debated which I wanted to post first, and decided to separately post two of my favorites.  First, below, from the indefatigable Bill Napier; and a second less familiar but welcome voice, anthropologist Terry Jones, PhD of the University of California Polytech State, San Luis Obispo, California.

Below is Napier’s abstract and here is a link to his full paper from the Journal of Cosmology.

Comets, Catastrophes, and Earth’s History

There is now compelling evidence that an exceptionally large (50-100 km) comet entered a short-period, Earth-crossing orbit some time in the Upper Palaeolithic, and underwent a series of fragmentations. During this disintegration the Earth was probably subjected to occasional episodes of intense bombardment. Such an episode might constitute a sensible astronomical framework for understanding the postulated catastrophe at 12,900 BP. Concentrations of sub- kilometre bodies may still exist in meteor streams and constitute a significant hazard. Such bodies are difficult to detect, and current deflection and mitigation strategies do not seem adequate to deal with them. For larger bodies, a paradox exists in that the number of comets expected to be thrown into Halley-type orbits (periods 20-200 years) is at least two orders of magnitude greater than observed. The fate of these comets is unknown, raising the prospect that a significant population of dark Earth-crossing comets may exist and adding further uncertainty to impact hazard assessments. Discrete bombardment episodes are evident in the well-dated impact record of the past 250 Myr and several coincide with transitions between geological periods. There is evidence that these episodes have a ∼ 35-37 Myr periodicity, which may be connected to Galactic disturbances of the Oort comet cloud. The threshold for periodicity begins for impact craters >∼ 40 km in diameter; since this is also the threshold which impact ejecta create worldwide conflagration, it again implies that comets are a significant, if not dominant, component of the global impact hazard.  W. M. Napier, Journal of Cosmology, November 2009

One Response

  1. This very recent article provides some strong evidence from an astronomical perspective of frequent cosmic encounters, not only at 12,900 BP (the start of the Younger Dryas), but also for a number of other events since. What’s more, not only does the risk of more cosmic events of Tunguska-sized seem likely in the not so distant future, but those of even larger size are possible too. This is because there appears to be a recent exciting of comets in the Oort cloud. The possiblity also exists that many bolides even up to two kilometre wide have not as yet been detected. Thus, the very conservative estimates that are most often referred to are in err. I think too that the article by Dr. Napier goes a long way in placing the impact hypothesis as the most plausible explanation for the Younger Dryas cold interval.

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