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Halley's comet really was a harbinger of death, scientists suggest

December 20, 2013 10:37pm
Halleys Comet on the Bayeux Tapestry
Halley's Comet on the Bayeux Tapestry. Comets have always been seen as foreboding omens, as suggested by this tapestry image showing the appearance of Halley's Comet in 1066 just months before the successful Norman invasion of England. via Wikipedia
It may seem like superstitious lore, but Halley's Comet may actually have paved the way for the spread of plauge in the middle ages —making it a very real "harbinger of death".
A scientific examination of Greenland ice that settled in somewhere between A.D. 533-540 suggests that a part of Halley’s Comet may have landed on Earth, spreading dust in the air that brought about dramatic climate change and subsequently made humanity more vulnerable to the “Plague of Justinian” (a.k.a. the first manifestation of the terrifying Black Death plague that devastated Europe) in A.D. 541-542. The piece is believed to have crashed into Earth in A.D. 536.
The cold truth
Dallas Abbott, a research scientist from the Lamont-Doherty Earth Observatory at Columbia University, said that she and her associates found evidence of an extraterrestrial object hitting the ocean about 1,500 years ago
Abbott told LiveScience that her team discovered fossils of diatoms and silicoflagellates (small forms of marine life from the tropical ocean) embedded in the cold ice. Abbott and her team speculated that the impact of the cosmic fragment’s crash landing likely sent the tiny organisms torpedoing into Greenland.
In addition to the marine fossils, Abbott and her colleagues also found residue of atmospheric dust containing high levels of tin – a characteristic indicative of the dust’s unearthly origin – in the ice. Because the residue was supposedly deposited during spring in the Northern Hemisphere, Abbott’s team is convinced that the particles came from the Eta Aquarid (or Aquariid) meteor shower. 
Observable from Earth between April and May, the Eta Aquarids are debris from Halley’s Comet that separated from the icy space rock a few hundred years ago.
A bright conclusion
Halley’s path of motion permits it to pass by the Earth once every 76 years. Incidentally, the comet’s recorded appearance in Earth’s skies in A.D. 530 was one of its brightest.
"Of the two brightest apparitions of Comet Halley, one of them is in 530," said Abbott. "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."
A period of time in A.D. 533 during which the Earth experienced mild cooling could be attributed to the Eta Aquarids, but Abbott asserted that something more powerful was certainly responsible for the global dimming phenomenon that made the planet colder by about 5.4 degrees Fahrenheit (3 degrees Celsius) in A.D. 536-537.
While Abbott’s team remains uncertain about the dimensions and exact location of the debris that hit Earth, a 2004 study suggests that a comet fragment about 2,000 feet in width could have exploded in the atmosphere in A.D. 536-537, spreading dust and debris all over the planet and causing the aforementioned global cooling event.
“There was, I think, a small volcanic effect,” Abbott said, referring to traces of evidence in the Greenland ice core that also point to the occurrence of a volcanic eruption in 536 A.D. Nevertheless, Abbott believes that the eruption could not have been enough to cause massive climate change.
"But I think the major thing is that something hit the ocean." — TJD, GMA News

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