Compare asteroid and comet in shape, size and composition.

An asteroid is a huge rock with no definite shape and consists of a variety of rocky rocks, also includes iron, nickel. The comet has a solid core and a peculiar atmosphere with a long tail that appears when the comet approaches the Sun. The composition of the core includes rocky rocks, water ice, and also carbon dioxide, methane and ammonia ice are observed in the composition of comets. A comet, unlike an asteroid, has a long tail consisting of water vapor, gases and dust, but asteroids can be much larger than the comet’s nucleus.