OAS NOVEMBER 20013 ASTRONOMY EZINE VOL 2 | Page 24

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Like many amateur and professional
astronomers alike, I am excited about viewing comet ISON. If the hype turns out
to be correct then we may be able to see this wonder with the unaided eye. Before
we get into what a comet is and some details on the comet, let’s have a little look
at some of the myths surrounding comets from bygone years and present day
myths, and to some extent scare mongering that has popped up on the internet
and mainly YouTube.
Before humanities understanding of the cosmos, before our understanding of nature, humans associated things that they did not understand with the paranormal.
Be it a solar eclipse, Vikings thought they had angered one of their Gods, and the
God was swallowing up the sun, th ey would chant or scream at the sky and of
course the eclipse would come to an end. Today we know what natural event causes solar and lunar eclipses.
Comets were thought by some ancient cultures to be the harbingers of doom, or
messengers from mythical Gods. Today we have the power of global communications, and such stories and myths pop up on places like YouTube. One such story
is NASA is covering up what comet ISON really is! Believers or conspiracy theorists
propagate a myth about a rogue planet that sweeps through our solar system every 3600 years called Nibiru or planet X. They believe that ISON is this planet or
brown dwarf star.
However all these claims are baseless and untrue, Comet ISON is just that, a comet.
Comets have been dubbed ‘Dirty Snowballs’ but why? Comets are interesting celestial bodies; they originate out in the Kuiper belt and Oort cloud region. This area
is the outer limits of our solar system, where it is cold. Gravity pulls together
lumps of rock, dust, gases and water* to form these dark bodies. * water is frozen
It is thought like asteroids, comets were formed with leftover material from when
the solar system was formed. Comets are hard to detect from Earth, they are
dark or have a low albedo.
“Albedo- Reflection coefficient, In Latin means Whiteness or reflecting
power”
Comets can orbit the sun much like planets, however there orbits can be long and
take many thousands of years, or once in a lifetime opportunities to view like Halley's comet. Comets can also sit out in the outer reaches and events such as a collision can send those inwards.
It is only when they venture into the inner solar system that comets start to become more visible, certainly more visible to the amateur astronomer. As they
move in, energy from the sun in the form of the solar winds and radiation pressure
causes the volatile gases and ices to melt. The main body of the comet, the nucleOAS EZINE