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Nov 22, 2004
What's in a Comet's Tail?

According to standard theory, a comet forms a head and tail because ices -- water and other frozen gases -- are heated enough to sublimate and to escape from the nucleus. Thus, a comet is thought to be composed of ices, distinguishing it from an asteroid, which is thought to be composed of rocky material.

According to Electric Universe theory, comets and asteroids are not necessarily of different composition -- it is the long oval orbit through the solar electrical field that makes a comet grow a head and tail.

When comet Shoemaker-Levy 9 broke apart, astronomers reasoned that the fractured nucleus would expose fresh ices that would sublimate furiously. So several ground-based telescopes and the Hubble Space Telescope trained their spectroscopes on the tails of the fragments of SL-9, looking for traces of volatile gases. None of the gases were found.

But an interesting event occurred while the Hubble Telescope was observing one of the larger fragments (fragment G) on July 14, 1994. The telescope observed a 2-minute long outburst of emission from ionized magnesium followed 20 minutes later by a 3-fold increase in the sunlight scattered by the dust. During the outburst, the color of the reflected sunlight also changed dramatically, brightening much more at longer wavelengths (red end of the rainbow) than at shorter wavelengths (blue end of the rainbow).

Outbursts like these (electric discharge), rather than subliming ices, are how Electric Universe theory expects comet tails to be produced. Because electric discharges are capable of removing solid material from surfaces, no volatiles are necessary, not on the surface and not in the core of the nucleus. The comet will produce a tail when its electrical stress reaches the critical point at which its plasma sheath begins to glow, no matter what its composition.



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