‘Cloud of Urt’ is a cluster of so many celestial objects further than Pluto in our solar system. Revolving around sun in an orbit of ellipse, these objects are then called Comets, which are formed from icy rocks and dust.
The icy rock of a comet is vaporized when it gets closer to sun and forms a gleaming tail. Understandably, the tail is in its longest position from the sun when the comet is nearest to the sun. Then, when it gets farer from the sun, the tail becomes smaller, and later disappears. Therefore, even though it is not a star and the tail is temporary, sometimes it is called ‘Tailed Star’.
There are more than 750 orbits of comets that have been known. A comet that has been popularly recognized is Halley. This name is after Edmond Halley, a scientist who studied it thoroughly. Comet Halley appears every 76 years, and last time it appeared in 1986. Another comet is ‘Helibob’. This brilliant comet could be seen in 1997 for almost 19 months with bare eyes.
Basically, a comet is formed from water, CO2, ammonia, dusty particles, and frozen gases. Meanwhile, through a thorough study, it was found that the comet tail consists of HCN and CO molecules, which play important parts in the formation of such important substances needed for the basis of life. This fact leads into a theory that these molecules, carried by comet tails, are what resulted in the beginning of life in the earth long time ago. However, seemingly ancient people have different opinion about comets. They believe that comets caused war and other disaster, both natural and endemic. Nowadays, scientists have confirmed that a comet arrival is normal, so that people should not panic about it.
