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Comets. By: Christian Moreno, Kamryn Johnson, AND Emily McDonald. Make sure and take notes! =D.
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Comets By: Christian Moreno, Kamryn Johnson, AND Emily McDonald Make sure and take notes! =D
The word “comet” now used in all European languages , comes from the Greek word kometes meaning ‘the hairy one, but the earliest extant records of cometary observations date from around -1000 in China and probably from about the same time in Chaldea (around present-day Iraq). Ideas about the true nature of comets are available from the time of the rise of Hellenistic natural philosophy at about -550 when the Pythagoreans considered comets to be a kind of (wandering) planets that were seen rather infrequently and mostly near the horizon in the morning or evening sky. Aristotle in his Meteorology (ca. -330) relegated comets to the lowest, `sub lunar' sphere in his system of spherical shells and described them as `dry and warm exhalations' in the upper atmosphere. History of Comets
Location A comet orbits the Sun in a long egg-shaped path. It can take a comet anywhere from a few years to hundreds of years to orbit the Sun.
Physical Properties Comets may be icy bodies a few km or less in diameter. At smaller distances from the sun, the nucleus of a comet will begin to vaporize, thereby generating a large neutral atmosphere, or coma. Two tails are also produced, one of which consists of dust particles entrained in the coma gas during vaporization and then separated from the coma by radiation pressure, while the other consists of ionized molecules swept back by the solar wind.
FamousComets and their Revolutions Halley’s comet was discovered by Isaac Newton and Edmund Halley in 1680. Halley believed that the same comet had appeared about every 76 years, and he predicted that it would return in 1758. The comet did return in 1758 and was named Halley’s comet in honor of Edmund Halley. Halley’s comet’s last visit close to Earth was in 1986.
Sources http://www.eso.org/public/events/astro-evt/DeepImpact/Background/comet-history-1.html http://www.kidseclipse.com/pages/a1b3c0d5.htm
Did you pay attention… Or did you do this? it’s time to find out.
QUIZ • From what language did the word comet come from? • Halley’s comet was discovered by Isaac Newton and Edmund Halley in ________ • A COMET ORBITS THE SUN IN A LONG _____ -SHAPED PATH • what DOES THE WORD “KOMETES” MEAN? • What year did Halley's comet return?
Answers 1)Greek 2) 1680 3)Egg 4)The hairy one 5)1758