STARRY NIGHTS
by Gary Boyle

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May 5, 2004
Comet NEAT

Over the next week or so, you will have a rare opportunity to glimpse a naked eye comet. Comet NEAT will be visible, low in the western sky after sunset. Refer to the finder chart below to help you locate this interstellar visitor.

Unlike meteors that quickly are incinerated upon entering Earth’s atmosphere, comets slowly travel through space – millions of kilometres from us. In general, comets are not rare objects in the field of astronomy. Amateur astronomers and stargazers with decent backyard telescope can observe a few per year. However, the general public bares witness to a bright comet on average, about once per decade.

During its routine sky patrol, the Near Earth Asteroid Tracking (NEAT) system situated in California, found the illusive object on the night of August 24, 2001 when it was still a billion kilometres us. NEAT as well as other such robotic installations such as LINEAR in Lincoln, Nebraska, were designed to search for Earth crossing asteroids whose orbits could intersect ours for possible collision. In a few short years, over one thousand have been identified as potential candidates with none on collision course.

For centuries, keen eyed astronomers were credited for the discovery of a new comet by having it named after them, for example Comet Halley in honour of Sir Edmund Halley. Today’s technology has redefined to way new comets are discovered.

Superstition has always run high when a bright comet appeared in the ancient skies. This was a very bad omen as people believed a king would die, a plague or disease would ravage the land or a war would be fought. If these events did occur during an apparition – it was merely by coincidence. Even up till the return of Halley’s Comet in 1910, people feared death by the passage of a poisonous cloud from the comet. Gas masks and ‘comet pills’ were sold on street corners.

Comets are gigantic mountains of ice measuring five to ten kilometers across. They reside in the far reaches of our solar system. From time to time they wander to the inner solar system and are then trapped by the sun’s gravity. As the comet comes within some two hundred million kilometers of the sun, the hot solar winds react with the comet’s icy surface and form a cometary fog along with a dust and/or gas tail.

As the comet approaches the sun, it brightens and the tail grows. Comets usually round the sun with a close approach call perilion then hurled back into the depth to its origin like a slingshot. As the comet’s distance from the sun increases, the brightness and tail fade thus making is hard to see.

Try to observe this jewel of the sky as our distance is widening each night. This particular comet will not grace our skies for another 37,000 years.

Gary Boyle is a freelance astronomy educator and writer. He teaches astronomy to adult and children as well as hosts many summertime ‘Star Nights’ at Provincial Parks and campgrounds.
Visit his web site at: www.wondersofastronomy.com
Send Questions & Comments about the Starry Nights to Gary Boyle

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