2/19/2023 0 Comments Halleys cometHowever, 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.įollow Mike Wall on Twitter and Google+. It's unclear where exactly the putative comet chunk hit Earth or how big it was, she added. "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." "Of the two brightest apparitions of Comet Halley, one of them is in 530," 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.) 530 and was astonishingly bright at the time, Abbott said. Halley zooms by Earth once every 76 years or so. For that, something more dramatic is required. 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). ![]() ![]() 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. "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.Ĭertain characteristics, such as high levels of tin, identify a comet as the origin of the alien dust, Abbott said. The ice cores record large amounts of atmospheric dust during this seven-year period, not all of it originating on Earth. When the Battle of Hastings was fought in October the same year, the Norman troops, motivated by the sighting of Halley’s Comet months before, shouted Nova stella, novus rex, which meant 'a new star, a new king. The new results come from an analysis of Greenland ice that was laid down between A.D. Stellarium has estimated that Halley’s Comet was visible from London in May 1066.
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