What is the difference between an asteroid and a comet?

Comets are largely composed of ice, rock particles and organic matter. For this reason, they are sometimes called dirty snowballs. Asteroids are celestial bodies made of rocks and metals.

Comets and asteroids move around the Sun. However, the discreteness (how far from the circular shape exactly) of the orbits of the comets and asteroids is much higher than that of the planets. The orbits of comets are more irregular and far from circularity than those of asteroids. In other words, the distance they are closest to the Sun and the farthest from the Sun during their orbiting movements is very different from each other. The gravitational effects of the sun and other celestial bodies can change the orbits of comets and asteroids.