A meteor's tail is the visible streak of light that follows a meteor as it passes through the Earth's atmosphere. It is composed of dust and gas particles that are left behind by the meteor as it burns up in the atmosphere. The study of meteors and their tails is called Meteorology, which is an OLOGY with five letters. The small pieces of rock or dust that make up a meteor's tail are called Meteorites, which is an Ite with three letters.