Final answer:
Comets originate from the Oort cloud or Kuiper belt and may have eventful ends as a result of interactions with the Sun and planets, or through loss of volatiles over several perihelion passages.
Step-by-step explanation:
The comets that light up Earth's sky have their origins in the remote and icy regions of the solar system, either in the Oort cloud or the Kuiper belt. These celestial objects are preserved in a nearly unchanged state at temperatures close to absolute zero, making them some of the most primitive objects we can study. When a comet's orbit brings it into the inner solar system, it leaves its long period of dormancy. In the vicinity of the Sun, the comet's volatiles, such as water ice, start to evaporate, forming a head, or coma, and often a long, luminous tail that extends away from the Sun.
Eventually, comets meet different fates. A comet may survive many perihelion passages, significantly changing each time as it loses its icy volatiles. Alternatively, it may be drawn too close to the Sun or a planet, leading to a collision and its destruction, as in the case of Comet Shoemaker-Levy 9 with Jupiter. Also noteworthy is the Rosetta mission that improved our understanding of comets by visiting Comet P67 and revealing the complex process of volatile release from these 'dirty snowballs'.