The term comet comes from Greek and means long-haired star.
Comets are celestial bodies with a frozen core that can measure up to 100 km in diameter. They have highly elliptical orbits around the Sun. When they approach their perihelion, the Sun's intensive energy releases glowing gases and other particles which form the nebulous coma around the solid core. When a comet's perihelion is particularly close to the Sun, the Solar wind forces it to eject streams of dust and gas which form the so-called comet's tail.
Comets probably formed at around the same time as the other planets in the solar system. Only a very small number of the numerous comets in our Solar System are visible to the naked eye. Visible comets appear on average around once or twice per decade.
Comets used to be considered significant for astrological interpretation, particularly in Mundane Astrology. The comet's orbit was plotted in the horoscope to see if it made any aspects to other planets. One of the first practitioners of the theory of comets was Aristotle. He thought their appearance represented fire that originated from the Milky Way and that their vapours sank down to Earth and polluted the atmosphere, causing natural catastrophes. In general, comets were held to be harbingers of all kinds of disaster including war, uprisings, floods, plagues and famine. However, there are also examples of comets being thought to herald the birth of an important individual or time of change ("Star of Bethlehem"). But their sudden appearance generally caused panic. Since around the time of the Enlightenment they have ceased to have any significance in astrological interpretation, although some populist astrologers continue to stoke up fear of comets in order to gain more publicity in the popular media. One example of this was the attempt by some astrologers to link the appearance of Halley's comet in April 1986 with the Chernobyl nuclear disaster which occurred around two weeks later.
The German astrologer Schubert-Weller on the decline of the importance of comets in astrology: "Present-day astrology, with its focus on the Sun, Moon and main planets, would have appeared very strange to the Ancients. It was not only folk religion that saw the sky as being populated by animals, spirits, angels and all kinds of strange creatures that appeared as meteorites, comets and other celestial phenomena. A whole heavenly kingdom, a "heavenly earth" was thought to exist - and its significance for humans was mantically and astrologically interpreted."
- Periodic Comet Numbers (Current list of comets; Minor Planet Center (IAU))
- NASA: Near-Earth Object Program (Near-Earth Asteroids, Meteorites und Comets)
- Wikipedia: Divination by Astrological and Meteorological Phenomena (Chinese sightings of comets more than two thousand years ago)
- Asteroids and Comets (David McCann, 1997)
- Hale Bopp: Harbinger of Government Flop. (Comets in history; Deborah Houlding, 1997)
- Unexpected Visitors: The Theory of the Influence of Comets (Jonathan Flanery, 11/ 2005)
- Comets in Astrology - Possible meanings of these celestial events (Rod Chang, 2014; Astrodienst)
Notes and References
- Astronomer Tycho Brahe wrote about it