What's In a Comet?
Comets Lemmon and PanSTARRS
Is 2013 the year of the comet?
Even though we are only about a quarter of the way through the year of 2013, two comets have already appeared to viewers on earth and a third even brighter spectacle is predicted to light up the night skies during the upcoming winter months of November and December. This end-of-the-year arrival is named ISON and it could turn out to be one of the brightest comets to appear in several centuries.
Newton's Comet of 1680
Fear of Comets
Throughout history the appearance of a comet in the night skies has not always been welcomed with the open mind of scientific inquiry. More often than not, comets were seen as bad omens, associated with disease, misfortune and destruction. Part of the reason for these beliefs, may lie in the irregularity and unpredictable nature of comets. Even regularly repeating comets like Halley's, often brought widespread fear and superstition, whenever one of these appeared. In Switzerland Halley's comet has been blamed for earthquakes, illnesses, red rain and even the birth of two-headed animals, while in England the same comet was once linked to "Black Death" (bubonic plague).
Only with increased understanding of our solar system and the universe that surrounds it, has the fear of these extra-terrestrial phenomenon diminished.....Or has it?.... For just recently in 1997, the appearance of the Hale-Bopp comet spurred a cult belief that a huge UFO was hiding behind the highly visible comet and that this alien vehicle would destroy intelligent life on the planet Earth. Fanatical belief in this doomsday scenario resulted in the death of 39 members of "Heaven's Gate", who committed suicide in California, as the comet etched its way across the skies of the northern hemisphere. Hopefully, the comets of 2013 will not trigger such drastic examples of self-destructive behavior.
The Hale-Bopp Comet
How Comets Are Named
For many centuries comets have been named after the person who discovered the celestial body. For example, Halley's comet, which has been observed since Old Testament days, is actually named after English astronomer, Edmond Halley, who successfully predicted its cycle in 1705. Over the centuries almost every comet has been named after the scientist, who first spotted the odd-shaped object in the night sky.
Recently, this trend has been broken, as all three major comets of 2013 are named after astronomical groups or observatories, where the comet was first discovered. For example, Comet Lemmon takes its name from the Mt. Lemmon Observatory in the Catalina mountains, situated north of Tucson, Arizona. On a similar note, Comet PANSTARRS derives it name from the PANSTARRS project, located on Mount Haleakela in Hawaii. Formally known as the Panoramic Survey Telescope and Rapid Response System, PANSTARRS was set up to spot and identify objects that might approach our planet and cause local or widespread damage on the surface of earth. Although this comet was first found by such a watchgroup organization, in no way does it present a threat to our livelihood or existence.
The real celestial treat of 2013 may turn out to be Comet ISON. Short for International Scientific Optical Network, ISON is actually a group of amateur Russian astronomers that operate observatories in 12 different countries, including Belarus and Russia. Furthermore, Comet ISON is a sungrazer, which providing it survives its close pass by the sun could produce one of best astronomical shows, since Newton's comet passed by the earth in the late 1600s. Despite its projected spectacular display, Comet ISON will come no closer than 39 million miles. Nonetheless, our planet could travel through the tail of this comet, an event that may produce some meteor showers.
Composition of Comets
Comets are composed of three parts; a head (or nucleus), a coma and a tail. The head is a concentrated conglomerate of ice, dust, and small rocky particles that form the core and densest part of the comet. Streaming out from the head there is usually (but not always) a coma and a tail. The coma is likened to the atmosphere of a planet, as it is a collection of dust and gases that streams out from the nucleus. Further out from the main part of the comet, dust trails can be seen streaming far away from the head. This is the tail of the comet.