What is the bright “tail” of a comet made from?

A comet’s bright tail is made of gas and dust that escape when the comet gets close to the Sun. The Sun’s heat melts the comet’s icy surface, releasing gas and tiny dust particles into space. The solar wind—a stream of charged particles from the Sun—blows this material away from the comet, forming a tail that always points away from the Sun. Most comets have two tails: a gas (ion) tail, which is bluish and straight, and a dust tail, which looks white or yellowish and curves slightly. These tails can stretch millions of kilometers long.