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Why do comets tails come out of the front and curve around to the back?

by Cbray
Tags: comets, curve, tails
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Cbray
#1
May1-11, 04:41 AM
P: 135
I've been researching this for a while now, and none of the theory's can predict it.
I've studied comets for a while now, and the tails come out of the front and then has a weird curve which goes to the back.
If you guys have any random ideas or thoughts of why this is happening, that would be awesome.

It's been stuck in my head for a while now,
thanks,
Charles.
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Vanadium 50
#2
May1-11, 08:29 AM
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P: 16,369
Quote Quote by Cbray View Post
I've been researching this for a while now, and none of the theory's can predict it.
Baloney. Sorry, but that's the only sensible word for claiming that just because you don't understand something that therefore nobody understands it.

Comet tails do not come "out the front". A comet has a coma, which would be spherical, caused by the heating of the comet as its orbit nears the sun. This coma is distorted by the bow shock as the comet passes through the solar wind. On the trailing edge, a comet has two tails: one made of gas and ions and the other of dust. These point in different directions - the dust remains in the orbit ellipse and the gas and ions are pushed away from the sun.
zhermes
#3
May1-11, 03:46 PM
P: 1,261
Quote Quote by Cbray View Post
I've studied comets for a while now, and the tails come out of the front and then has a weird curve which goes to the back.
What you're describing isn't the paradigmatic 'comet' that most people imagine... do you have a particular image you're thinking about?

Comet tails are caused by a few effects, the dominant one is simply heating and radiation pressure from the sun. The heat from sunlight evaporates (and ionizes) volatiles on the surface of the comet facing predominantly toward the sun, and then radiation pressure pushes the material away from the sun (regardless of the comet's trajectory---for the most part).

Generally this looks like a thin pseudo-atmosphere, roughly spherical around the comet, followed by a tail pointing away from the sun. I suppose (conjecturally), that particular comet structures (e.g. anisotropic distribution of ices on the surface, and particular volatile compositions) could lead to a more collimated outflow in a particular direction which takes some time for radiation pressure to redirect. This might be more likely if a large amount of the ejected material is heavier dusts (instead of just gas).


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