Beautiful and fleeting, if you miss her once, you won’t get another chance for a long time.
Comets have been observed for centuries, with some documentations going back to B.C.E. For this particular comet, the first recorded sighting was by Chinese astronomers in 240 B.C.E. However, it wasn’t until 1705 that it was identified by English astronomer Edmond Halley. He published the first catalog of the orbits of comets, providing information on 24 different comets. What is even more special about this catalog, however, is the claim that he made in it. Halley posited that comets that were observed in 1531, 1607, and 1682 were all the same comet, due to the fact that the three sightings all had incredibly similar orbits. He believed the comet would return to Earth every 76 years, predicting its return in 1758. While Halley did not live to see his prediction come to pass, the return of the comet in late 1758 resulted in it being named in his honor.
Halley’s has also provided valuable scientific knowledge to the astronomical community since its documentation. It’s nearly identical orbit and it’s ability to be predicted proved that it maintains an orbit around the sun, showing scientists that it is possible for some comets to be considered part of the solar system, as they maintain an orbit around the central point.
The comet was first imaged in 1982, 4 years before its next passage of Earth, when it was pictured near Saturn using the 200-inch Hale Telescope at Palomar Observatory in California. In 1986, the comet came closest to Earth at 39 million miles. While this may seem close considering the vastness of space, in 1910 it’s passage was at 13.9 million miles, and the comet’s closest passage past Earth occurred on April 10, 837, with a distance of 3.7 million miles. This passage is actually depicted in the Bayeux Tapestry from that time period.
Halley made history as the first comet to be imaged by interplanetary space craft around its passage in 1986. Two Japanese spacecraft, two Soviet spacecraft, and one European Space Agency spacecraft were within imaging distance. The European Space Agency craft (named Giotto) passed only 370 miles from the comet’s nucleus, with images and measurements taken to show that the nucleus’s crust was so black (blacker than coal) that it only reflected 4% of the sunlight it received.
While many of us were not alive to see the last time Halley visited, there’s no need to worry. She’s coming back to the solar system in 2061! 42 years and counting!
Until then, every October, the Orionid Meteor Shower is spawned by Halley’s fragments. If October is too cold for you, Halley also spawns the May Eta Aquarids Meteor Shower. In addition, there is a collection of comet’s called “Halley family comets” (HFC) that have similar inclinations of orbit to Halley. However, the inclinations vary, resulting in some astronomers hypothesizing a separate origin from Halley. Some believe they could have come from just past Neptune, or that they evolved from members of the Oort Cloud.
Regardless of whether you’re tuning in for Halley’s next passing, or will catch one of the smaller showers or family comets, the study of these gas jets hurtling through space brings astronomers closer to understanding the great expanse of the universe with every observation.
Sources:
https://www.space.com/19878-halleys-comet.html
https://www.britannica.com/topic/Halleys-Comet