Halley’s Comet is arguably the most celebrated celestial object. It does in a sense, provide the link between humanity’s belief in superstition and science. In its previous appearances, Halley’s Comet was often viewed as a bad omen. The most famous case its appearance before the Battle of Hastings in 1066. King Harold II viewed it as a bad omen and suffered mortal wounds during the battle. Halley’s Comet also represents a triumph of science. Utilizing Kepler’s Laws of Motion, Edmond Halley predicted the comet that had appeared in 1682 would reappear in 1759. Halley died in 1743, but when the comet made its predicted appearance, it was named in Halley’s honor.
The first known recorded appearance of Halley’s Comet was in 240 B.C. Chinese astronomers referred to comets as “Broom stars” that appeared in the sky for weeks at a time. The comet has returned roughly every 76 years since. The size and brightness of the comet varies on each visit due to its distance from the Earth on each visit and increasing light pollution on Earth. The closest the comet has been to the Earth was in 837. Halley’s came within 4 million miles of Earth and its tail was 90 degrees. This is the equivalent distance from the horizon to directly overhead. Halley’s last appearance in 1985-86 was somewhat disappointing. Its closest approach to Earth was 38 million miles and while visible, was not quite the remarkable sight that it had been in earlier visits. However, it was during that approach the Giotto probe was able to take photographs 376 miles from the comet nucleus. Below are images of Halley’s Comet recorded during its prior visits.
This is part of the Bayeux Tapestry commemorating the Battle of Hastings in 1066. The comet appears in the image top center. King Harold II of England took it as a bad omen and indeed, he was killed in the battle. William the Conqueror of Normandy won the battle and pronounced himself King of England. This tapestry can be viewed by the public in the Bayeux Tapestry Museum. Bayeux, incidentally, is located just a few miles from the American D-Day landing site on Omaha Beach.
This painting by Giotto di Bondone of Italy called Adoration of the Magi. A comet is used to represent the Star of Bethlehem. Painted in 1304, three years after Halley’s appearance in 1301, the comet appears top center and is generally believed to be derived from the appearance of Halley’s Comet. It is located in the Cappella degli Scrovegni in Padua, the same town Galileo would make historic observations with his telescope in 1610. In 1986, the European Space Agency (ESA) named it’s Halley’s Comet space probe Giotto, in honor of the artist.
This is a painting by Samuel Scott in 1759. The scene depicts Halley’s Comet over London. Westminster Abbey is visible to the far left. This was the appearance predicted by Edmond Halley, who had passed away 15 years earlier.
Halley’s appearance in 1910 provided astronomers with the first opportunity to photograph the comet. This series of photographs shows the comet over a two month period as it approached and then receded from Earth. The images were taken from Mt. Wilson’s 60-inch telescope. This was one of Halley’s most celebrated appearances. It’s tail stretched 30 degrees across the night sky. In fact, on May 18, 1910, the Earth passed through the tail of Halley’s Comet. Entrepreneurs sold “comet pills” which were supposed to counteract the effects of cyanide gas which had been detected in the tail. Of course, the tail is far too tenuous to have any effect on life on Earth.
The front page article from the New York Times of this event is quite interesting. Mark Twain, who was born a couple of weeks after the previous visit by Halley’s Comet in 1835, predicted in 1909 that, “I came in with Halley’s Comet in 1835…and I expect to go out with it.” Mark Twain died on April 21, 1910.
While Halley’s last appearance in 1986 may have been disappointing to earthbound viewers, it provided us with the first space mission (Giotto) to a comet. The nucleus of the comet is approximately 16 x 8 x 8 kilometers. The closest image was taken 95 seconds prior to Giotto’s nearest approach, which was 376 miles. The nucleus itself is one of the darkest objects in the solar system. It is, in fact, darker than coal. The jets are emanating from the sunlit side are not uniform in nature. This could account for some of the irregularities detected in the orbit of Halley’s Comet. The comet will begin its next approach to the Sun in 2024, and will be visible on Earth again in 2061.
*Image atop post is engraving from Halley’s 1682 visit. Edmund Halley was 26 years old during this visit.