The close approach of a comet is one of the most spectacular sights in heavens The comet appears first in the telescope as a small, fuzzy, faintly luminous object. At this point is far from the earth, but is approaching our planet on the inward leg of a long journey from the the solar system. As it comes closer, solar energy warms the head of the comet and vaporizes gases that were frozen in solid crystals during many years in which the comet was far from the sun. These gases stream out behind the comet's head. Excited to luminescence by the absorption of solar radiation, the stream of gases forms spectacular, glowing tail, which becomes clearly visible to the naked eye as the comet nears the sun