[meteorite-list] Astronomers Suggest Comet To Blame for 6th-Century 'Nuclear Winter'

From: Sterling K. Webb <kelly_at_meteoritecentral.com>
Date: Thu Apr 22 10:31:20 2004
Message-ID: <402056D0.10C72D5E_at_bhil.com>

Hi,

    The "comet" theory is not new nor original with these researchers. There
is a book published 4-5 years ago by Baille (title now forgotten by me) that
advance the same explanation for the same phenomenon.
    The "bad years" of 536-540 AD are a world-wide event. In fact, it seems
to have been at its very worst in SW China, where according to the
chronicles, "the sun was not seen for three years"! Crops failed totally,
and everything was covered with dust a foot deep.
    This description has given rise to the alternative theory of these
events, which is that there was a volcanic eruption of tremendous size and
world-wide effect. The culprit that is advanced is Krakatoa, which did have
a massive early episode sometime between 500 BC and 1000 AD, one 10 times
bigger than the 1883 episode.
    However strata from this earlier event are hard to find and none that
have been found have been datable with any precision, so it remains only a
possibility, but not a proven one.
    The greatest volcanic event of the last 500 years was "Tambora on the
island of Sumbawa in Indonesia in 1815, a 13,000-foot volcano that belched
f1ame and ash from April 7 to 12, 1815; and rained stone fragments on
surrounding villages. It has been estimated that Tambora's titanic explosion
blew from 37 to 100 cubic miles of dust, ashes, and cinders into the
atmosphere, generating a globe-girdling veil of volcanic dust."
    This produced "The Year Without A Summer" world-wide in 1816. For
fascinating details, see: <http://wchs.csc.noaa.gov/1816.htm>. Of course,
the effects described in this fascinating piece of history could just as
easily have been produced by a "insignificant" little 150-200 meter comet.
At the time (1816), the cause was complete mystery (except to Benj.
Franklin, who hypothesized the cause to be volcanic dust). Tambora was not
identified as the culprit for almost a century (1913).


Sterling K. Webb
--------------------------------------------------------------------------------

Bernhard \"Rendelius\" Rems wrote:

> I mean, do they offer some PROOF for their theory? A "plume" is nothing
> that would have gone unobserved by the eye (left alone a comet exploding
> in the sky) - and as much as I know, the "mini ice age" at that time
> wasn't a global occurence, but rather a european one - at least to my
> knowledge. There has been a second "mini ice age" around 1500 in Europe,
> and this is either attributed to the Maraunder solar minimum or the
> change of the gulf stream.
>
> Bernhard
>
> -----Original Message-----
> From: meteorite-list-admin_at_meteoritecentral.com
> [mailto:meteorite-list-admin_at_meteoritecentral.com] On Behalf Of Ron
> Baalke
> Sent: Tuesday, February 03, 2004 5:39 PM
> To: Meteorite Mailing List
> Subject: [meteorite-list] Astronomers Suggest Comet To Blame for
> 6th-Century 'Nuclear Winter'
>
> Contact: Dr Derek Ward-Thompson derek.ward-thompson_at_astro.cf.ac.uk
> 029-2087-5314
> Cardiff University
> February 3, 2004
>
> Astronomers unravel a mystery of the Dark Ages
>
> Undergraduates' work blames comet for 6th-century "nuclear winter"
>
> Scientists at Cardiff University, UK, believe they have discovered the
> cause of crop failures and summer frosts some 1,500 years ago - a comet
> colliding with Earth.
>
> The team has been studying evidence from tree rings, which suggests that
> the Earth underwent a series of very cold summers around 536-540 AD,
> indicating an effect rather like a nuclear winter.
>
> The scientists in the School of Physics and Astronomy believe this was
> caused by a comet hitting the earth and exploding in the upper
> atmosphere. The debris from this giant explosion was such that it
> enveloped the earth in soot and ash, blocking out the sunlight and
> causing the very cold weather.
>
> This effect is known as a plume and is similar to that which was seen
> when comet Shoemaker-Levy-9 hit Jupiter in 1995.
>
> Historical references from this period - known as the Dark Ages - are
> sparse, but what records there are, tell of crop failures and summer
> frosts.
>
> The work was carried out by two Cardiff undergraduate students, Emma
> Rigby and Mel Symonds, as part of their student project work under the
> supervision of Dr Derek Ward-Thompson.
>
> Their findings are reported in the February issue of Astronomy and
> Geophysics, the in-house magazine of the Royal Astronomical Society.
>
> The surprising result of the new work is just how small a comet is
> needed to cause such dramatic effects. The scientists calculate that a
> comet not much more than half a kilometre across could cause a global
> nuclear winter effect. This is significantly smaller than was previously
> thought.
>
> Dr. Ward-Thompson said: "One of the exciting aspects of this work is
> that we have re-classified the size of comet that represents a global
> threat. This work shows that even a comet of only half a kilometre in
> size could have global consequences. Previously nothing less than a
> kilometre across was counted as a global threat. If such an event
> happened again today, then once again a large fraction of the earth's
> population could face starvation."
>
> The comet impact caused crop failures and wide-spread starvation among
> the sixth century population. The timing coincides with the Justinian
> Plague, widely believed to be the first appearance of the Black Death in
> Europe. It is possible that the plague was so rampant and took hold so
> quickly because the population was already weakened by starvation.
>
> ###
Received on Tue 03 Feb 2004 09:20:01 PM PST