Comets are small Solar System bodies containing mixtures of ice, dust, and rocky material. When a comet approaches the Sun, some of its frozen material can become gas and carry dust away from the central body. This activity creates the extended appearance associated with a bright comet. Far from the Sun, the same object may be much less conspicuous and difficult to distinguish against the background of space. The solid central part of a comet is called its nucleus. Around an active nucleus, released gas and dust can form a diffuse region known as a coma. Material extending away from this region may produce tails. These visible structures are much […]
