I don't know how many of you are astronomers, but there was a great view of comet Ikeya-Zhang tonight from 29.070882 N, 81.332625W (Glenwood, Central Florida...If you have a GPS, come visit :) ).
I have wondered how OUC's (that would be old universe creationists) consider the (apparent) lack of longevity of comets in our system.
Whipple's dirty iceberg theory claims that a comet's nucleus is only a few kilometers across and is comprised of ice and dust. At distances close to the sun, some ice evaporates to produce the coma. If each close passage near the sun results in a large amount of material being removed from the nucleus, a comet shouldn't be able to survive many orbits. Some comets with short orbital periods have been observed to become noticeably fainter, presumably as a result of material lost to evaporation. I've recently read some estimations that a relatively bright comet cannot remain bright for more than a hundred or so passes. Comet Hyakutake, for example, has a period of about 10,000 years, and based on its magnitude, must not have been orbiting the sun for very long.
Are these comets picking up material, or are we picking up comets?
Troy.
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