A comet is an like icy clod of dirt made of frozen gases, rock, and dust, leftovers from the early formation of our solar system. Many comet-like bodies may have collided and stuck together to form the ancient core from which the giant planet Jupiter grew. In size, comets are often roughly the size of a small town. When a comet’s orbit brings it close to the Sun, it heats up and spews dust and gases into a giant glowing head larger than most planets. The dust and gases form a tail that stretches away from the Sun for millions of kilometers.