Comet - a small body in the solar system that orbits the Sun and has a so-called comma (atmosphere) and / or tail. Coma and tail of a comet - it effects the evaporation surface of the comet's nucleus under the influence of solar radiation. The core is made of stone, dust and ice.
Comets appear on the periphery of the solar system and their orbits are constantly changing under the influence of gravity major planets. As a result, some of the comets passing close to the sun, orbits the Sun destroys them when they are approaching it, other ice blocks ever leave the solar system. Bright comet - one of the most interesting cosmic phenomena always attracted attention.