What Is a Comet?

Answer:

A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma (a thin, fuzzy, temporary atmosphere) and sometimes also a tail.

Most observable comets in our solar system derive from the Oort Cloud, a hypothesized cloud made up of leavings from the sun. These materials form comets, which orbit the sun because they are affected by the gravitational pull of the sun and other planets.

As a comet gets closer to the Sun it moves faster and faster, because the closer an object is to the Sun the stronger the Sun's gravity acts on it. As well as moving faster near the Sun, the comet's tail will grow in length since more of the ice will be evaporating.