[meteorite-list] Why Halley's Comet May Be Linked to Famine 1, 500 Years Ago

From: Michael Bross <element33_at_meteoritecentral.com>
Date: Wed, 18 Dec 2013 19:26:32 +0100
Message-ID: <F590CCD1315346C3841B4C0B1F989AFD_at_DaDaPC>

Dear listees

Interesting...
Mid 90s I saw a great documentary on PBS about that period of famine
and the decline of the Roman Empire, with scientific evidences that the
Krakatoa
volcano in Indonesia was the reason.
Ice cores, texts from the Vatican talking about almost 30 years of dust
in the atmosphere and blurred sun, (not just 2 years !)

Now we hear about the Halley Comet.

Maybe it was both of them... because when I read "there was a small volcanic
effect"... Krakatoa is a major volcano on Earth and its eruption at that
time was a major
one: scientists identified the huge lava field in the ocean surrounding the
Krakatoa.

Anyway, very interesting

have a great evening
Michael B.





--------------------------------------------------
From: "Ron Baalke" <baalke at zagami.jpl.nasa.gov>
Sent: Wednesday, December 18, 2013 6:21 PM
To: "Meteorite Mailing List" <meteorite-list at meteoritecentral.com>
Subject: [meteorite-list] Why Halley's Comet May Be Linked to Famine 1,500
Years Ago

>
>
> http://www.space.com/24005-halleys-comet-linked-to-ancient-famine.html
>
> Why Halley's Comet May Be Linked to Famine 1,500 Years Ago
> By Mike Wall
> space.com
> December 18, 2013
>
> SAN FRANCISCO - The ancients had ample reason to view comets as harbingers
> of doom, it would appear.
>
> A piece of the famous Halley's comet likely slammed into Earth in A.D.
> 536, blasting so much dust into the atmosphere that the planet cooled
> considerably, a new study suggests. This dramatic climate shift is linked
> to drought and famine around the world, which may have made humanity more
> susceptible to "Justinian's plague" in A.D. 541-542 - the first recorded
> emergence of the Black Death in Europe.
>
> The new results come from an analysis of Greenland ice that was laid down
> between A.D. 533 and 540. The ice cores record large amounts of
> atmospheric
> dust during this seven-year period, not all of it originating on Earth.
>
> "I have all this extraterrestrial stuff in my ice core," study leader
> Dallas Abbott, of Columbia University's Lamont-Doherty Earth Observatory,
> told LiveScience here last week at the annual meeting of the American
> Geophysical Union.
>
> Certain characteristics, such as high levels of tin, identify a comet
> as the origin of the alien dust, Abbott said. And the stuff was deposited
> during the Northern Hemisphere spring, suggesting that it came from the
> Eta Aquarid meteor shower - material shed by Halley's comet that Earth
> plows through every April-May.
>
> The Eta Aquarid dust may be responsible for a period of mild cooling in
> 533, Abbott said, but it alone cannot explain the global dimming event
> of 536-537, during which the planet may have cooled by as much as 5.4
> degrees Fahrenheit (3 degrees Celsius). For that, something more dramatic
> is required.
>
> Ice core data record evidence of a volcanic eruption in 536, but it almost
> certainly wasn't big enough to change the climate so dramatically, Abbott
> said.
>
> "There was, I think, a small volcanic effect," she said. "But I think
> the major thing is that something hit the ocean."
>
> She and her colleagues have found circumstantial evidence of such an
> impact.
> The Greenland ice cores contain fossils of tiny tropical marine organisms
> - specifically, certain species of diatoms and silicoflagellates.
>
> An extraterrestrial impact in the tropical ocean likely blasted these
> little low-latitude organisms all the way to chilly Greenland, researchers
> said. And Abbott believes the object responsible was once a piece of
> Halley's
> comet.
>
> Halley zooms by Earth once every 76 years or so. It appeared in Earth's
> skies in A.D. 530 and was astonishingly bright at the time, Abbott said.
> (In fact, observations of Halley's comet go way back, with research
> suggesting
> the ancient Greeks saw the comet streaking across their skies in 466 B.C.)
>
> "Of the two brightest apparitions of Comet Halley, one of them is in 530,"
> Abbott said. "Comets are normally these dirty snowballs, but when they're
> breaking up or they're shedding lots of debris, then that outer layer
> of dark stuff goes away, and so the comet looks brighter."
>
> It's unclear where exactly the putative comet chunk hit Earth or how big
> it was, she added. However, a 2004 study estimated that a comet fragment
> just 2,000 feet (600 meters) wide could have caused the 536-537 cooling
> event if it exploded in the atmosphere and its constituent dust were
> spread
> evenly around the globe.
>
>
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Received on Wed 18 Dec 2013 01:26:32 PM PST