What are Halley's, Hale-Bopp, Kohoutek, West, Hyakutake and McNaught?
Comet Hale–Bopp indicated later that its comet nucleus was 60±20 kilometres in diameter, approximately six times the size of Halley. Its great distance and surprising activity indicated that comet Hale–Bopp might become very bright indeed when it reached perihelion in 1997. However, comet scientists were wary – comets can be extremely unpredictable, and many have large outbursts at great distance only to diminish in brightness later. Comet Kohoutek in 1973 had been touted as a 'comet of the century' and turned out to be unspectacular. Hale–Bopp became visible to the naked eye in May 1996, and although its rate of brightening slowed
Comet Hale–Bopp its previous perihelion 4,200 years ago, in July 2215 BCE. The estimated closest approach to Earth was 1.4 AU, and it may have been observed in ancient Egypt during the 6th dynasty reign of the Pharaoh Pepi II (Reign: 2247 - c. 2216 BCE). Pepi's pyramid at Saqqara contains a text referring to an "nhh-star" as a companion of the pharaoh in the heavens, where "" is the hieroglyph for long hair. Hale–Bopp may have had a near collision with Jupiter in early June 2215 BC, which probably caused a dramatic change in its orbit, and 2215 BC may have