Final answer:
A comet's tail, which grows as the comet approaches the Sun, consists of two parts: a dust tail made of particles dispersed along the comet's orbit, and an ion tail of ionized gases pushed away by the solar wind. Both tails always point away from the Sun due to the influence of the solar wind and radiation pressure.
Step-by-step explanation:
The tail of a comet grows as it approaches the Sun, due in part to the sublimation of its icy components. This process releases gas and dust, which form two distinct types of comet tails: the dust tail and the ion tail (also known as the gas tail). The dust tail appears bright and curves slightly as it is composed of smoke-sized particles that spread out along the orbit of the comet and are pushed by photons from the Sun. In contrast, the ion tail, made up of ionized gas, is straighter and fainter, as it is swept directly away from the Sun by the solar wind.
It is a common misconception that comet tails trail behind them like a tail; in fact, they always point away from the Sun. This counterintuitive behavior is due to the combined effects of the solar wind on ionized gas and the radiation pressure on dust particles, which both act to push the tail materials away from the Sun.