Comets are irregular
chunks of ice and dust, presumed to be left over form the formation of the
solar system. These chunks of ice and dust are thought to begin their
journey in a region of space know as the Oort cloud well beyond the orbit
of Pluto. These cosmic visitors are thought to be knocked out of their
resting places in the Oort cloud by object beyond the solar system and
then they proceed to begin their journey inward toward the center of the
solar system
As a comet approaches
the inner solar systems, temperatures, solar radiation and the solar wind
all begin to increase. At first the comet will begin to warm and begin to
expel gas from it's nucleus. When this happens the comet forms a coma. As
the comet gets closer to the sun, the coma gets hit by increasing solar
winds and so the coma is blow back behind the comet. When this happens the
comet develops a tail. This is, in a nutshell, why comets look as they do
when we see them in the sky.
So, with there being
so many comets moving about the solar system it stands to reason that
there is a comet visible at almost any night during the year (in small
telescopes). Most of these comets have been discovered in the last 10
years as several automated comet searches have been developed. But too me,
the idea of comet watching form night too night still gives me great
pleasure. To watch a comet cross a constellation or even just a few
degrees of sky over a week's time, too me, is quite an event.
While working at the
observatory, I had the chance to snap a few pictures of comets. Bear in
mind, these picture are taken from the city and most comets imaged are
from close to the horizon so the images aren't all that great.