Although the beauty of comets is unsurpassable,
they are merely giant balls of frozen water. Yes, that's right, comets
are blocks of frozen ice mixed with cosmic dust. There is also a
small percentage of ammonia, methane, and CO2.
They are described as snowballs(frozen ice) that have become dirtied
by the dirt(cosmic dust) that is washed up by the cars going by.
These chunks are theorized to have originated from the forming of
giant planets like Saturn, Jupiter, Neptune, and Uranus, and each comet
is usually the size of one of the Rocky Mountains. There are four
parts to a comet: nucleus, coma, plasma tail, and dust tail. The
nucleus is the only permanent part of the comet. Although it has
never been seen, there is no doubt of its existence. The brightness of
the comet can depend on how large the nucleus' diameter is since these
spherical forms can scatter sunlight like a mirror. |
Image: Comet
Image Source: Views
of the Solar Sytem
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Comets are created
all the time. There is an estimated trillion comets on the edge of
the solar system. Yet, visibility of comets is very susceptible
to light pollution, and because of the growing population and pollution,
fewer and fewer comets are being seen.
Image: Comet
Image Credit: Comet
Hyakutake site
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When
the comet passes close to the sun, it changes from a solid state to a gaseous
one because of the intense heat. When this happens, it releases gas
and dust, which forms more or less a circle around it. This is when
the comet becomes more visible. The coma absorbs more light than
it reflects, but it still reflects a small percentage of it.. The
coma tends to blend in with the tail because some of the gas is mixed in
with the tail debris. The plasma tail is a tail of ions. This tail
only appears separate from the dust tail if its direction is perpendicular
to the orbit of the comet's plane, otherwise, it will blend in with the
dust tail. The dust tail is the most stunning and beautiful of the
comet, often being striped with different colors from different types of
gases. The dust tail always faces the opposite direction of the sun
because of the exerts a repelling force. The dust tail is nothing
more than gases, particles, and cosmic dust that is forced back from the
coma from the repelling force, but still held in by the pull of the nucleus,
creating an amazing thing to see across the sky. Most comets do not
pass Neptune, but some slip past and venture in closer to the Earth's pull.
When it comes closer to the sun is when the dust tail forms, and gets pulled
in close for a good look. The dust tail can sometimes be up to 100
kilometers long.
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