Comets are the largest objects in our Solar System. They can measure up to ten miles across and have tails that can extend millions of miles into space.

    Comets are often called “dirty snowballs” because the solid center of a comet, called a nucleus, contains rock particles trapped in frozen liquid.

    As a comet moves closer to the Sun, the heat from the Sun turns the outer ice into gas and the solid particles are released as dust. These gas and dust particles trail the comet in the form of a tail.

    Sometimes two tails can be seen, a gas tail which is bluish in color, and a dust tail that looks yellowish. Because the tail of a comet is always pushed away from the Sun by solar winds, the tail can be either in front of the comet or behind it.