Comets
CometsCOMETS
Comets have been witnessed ever since man has been speculating about objects in the nighttime sky and appear in records from the beginning of recorded civilization (Schweighauser 20).
Comets are made up of four distinct features. The first is the nucleus. The nucleus is made up of frozen gases, mostly water vapor with lesser amounts of carbon dioxide and carbon monoxide, and imbedded in the frozen gases are interplanetary dust and tiny fragments of stony and metallic meteoric material. Some comets, the larger ones, have a nucleus of 10 kilometers (Schweighauser 22).
The second feature of comets is the coma. The coma is composed of atoms and molecules of gas that travels with the nucleus. The coma may be up to 100,000 kilometers in diameter. The third feature of a comet is the head. The head is just the name given to the coma and nucleus.
The last of the features of the comet are the tails. Most comets have two tails. One tail is made from dust particles and the other, called ion tail, is made gases. As a comet approaches the sun, the frozen gas becomes unfrozen which causes the dust particles to become free. Light pressure from the sun and some other forces cause these materials to move away from the head of the comet and in the opposite direction...
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