Scientists track meteor shower to unusual comet seen every 4,000 years

It's hard to call a path well-worn when something passes by only once every 3,967 years. But it turns out that type of long-period comet can still be tied to a specific meteor shower, as scientists have done with Comet C/2002 Y1 Juels-Holvorcem and the UY Lyncids shower.

Comet C/2002 Y1 Juels-Holvorcem most recently made a close approach of the sun in 2003 — which means its last such visit was around 2,000 B.C., when Egypt's Great Pyramids were just a few hundred years old, and its next pass of the sun won't occur until nearly the year 6,000.

Looking at such huge amounts of meteor sightings, scientists can pick out subtle meteor showers based on tracking only a few shooting stars to similar origin points in the sky, called radiants. So astronomers combined that analysis of a decade of observations with NASA's database of comets and their orbits.

The scientists found at least nine new matches between meteor showers and long-period comets, and identified another six potential matches. The research tracks down the comets responsible for esoteric meteor showers, like December's sigma Virginids and July's Pegasids, caused by debris from C/1846 J1 Brorsen and C/1979 Y1 Bradfield respectively.

Most of the comets in the research swing past the sun every 400 to 800 years or so, a quite respectable calendar. Three comets joined Juels-Holvorcem is a bit of an outlier with orbits longer than 1,000 years.

Among the meteor showers studied, the researchers noticed an intriguing trend: Displays from long-period comets tend to last several days, and the radiant appears to move like a smudge on the sky. The scientists on the new research think the effect may be caused by a comet's orbit shifting between loops...

[snip] The first known observation of Halley's took place in 239 B.C., according to the European Space Agency. Chinese astronomers recorded its passage in the Shih Chi and Wen Hsien Thung Khao chronicles. Another study (based on models of Halley's orbit) pushes that first observation back to 466 B.C., which would have made it visible by the Ancient Greeks.

When Halley's returned in 164 B.C. and 87 B.C., it probably was noted in Babylonian records now housed at the British Museum in London. "These texts have important bearing on the orbital motion of the comet in the ancient past," noted a Nature research paper about the tablets.

This portion of the Bayeux Tapestry shows Halley's Comet during its appearance in 1066.

Another appearance of the comet in 1301 possibly inspired Italian painter Giotto's rendering of the Star of Bethlehem in "The Adoration of the Magi," according to the Britannica encyclopedia.Halley's most famous appearance occurred shortly before the 1066 invasion of England by William the Conqueror. It is said that William believed the comet heralded his success. In any case, the comet was put on the Bayeux Tapestry — which chronicles the invasion — in William's honor.

Astronomers in these times, however, saw each appearance of Halley's Comet as an isolated event. Comets were often foreseen as a sign of great disaster or change.

Even when Shakespeare wrote his play "Julius Caesar" around 1600, just 105 years before Edmond Halley calculated that the comet returns over and over again, one famous phrase spoke of comets as heralds: "When beggars die there are no comets seen; The heavens themselves blaze forth the death of princes." [/snip]
Halley's Comet: Facts About the Most Famous Comet By Elizabeth Howell over 3 years ago

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