Halleys Comet Essay

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HALLEY’S COMET Ancient Chinese astronomers discovered Halley’s comet in prehistoric times in approximately 240BC. This is however is debated as there is a possibility that an ancient Greek celestial event in 466BC may be evidence of a sighting of Halley’s comet which lasted 80 days. Edmond Halley discovered Halley’s orbit pattern and more information about the comet in 1705. Later on, roughly 12 years after his death his information was proven and it was thus named after him. Halley’s Comet was last seen on the 9th February 1986. There was much disappointment to this appearance as unlike in previous sightings it was barely visible to the naked eye. It was the least favorable sighting as the earth as the comet was on opposite sides of the sun during the time of the sighting. In addition increased light pollution from urbanization caused many people to never see the comet at all. The length of Halley’s comets orbit is approximately 76 years, though it has varied from 74-79 years since 240BC. The perihelion, the point in which the comet’s orbit is nearest the sun is just 0.6AU and when furthest from the sun 35AU (roughly the distance of Pluto). Unusual for an object in the solar system, Halley’s comet ‘s orbit is retrograde, orbiting the sun in the opposite direction to the planets. Halley’s is expected to next appear on 28th July 2061. It is expected to be in a better position for observation than in 1986 as the earth and the comet will be on the same side of the earth and is expected to have a magnitude of -0.3 compared with only +2.1 in 1986. Halley’s comet has been sighted many times in many generations and actually had an impact on history. It was sighted in the year 1066AD prior to the famous battle of Hastings, when the forces of England were defeated by the Norman invader William the Conqueror. Comet Halley is featured in a famous portion of the
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