This is also a celestial body and so belongs to a solar system. It is made up of small particles firmly fixed in a gas cloud.

A large comet consists of a head, with a long glowing tail behind. Because of this they are sometimes called 'tailed stars'. The smaller ones have no tails and look like normal stars. When a comet nears the sun some gas escapes. This ignites with the sun's heat to form the comet's tail, which is always away from the sun. Sometimes comets are called the 'wandering stars' of the solar system. This name is inaccurate; comets move around the sun in very regular orbits. Once, the appearance of a comet was thought to foretell a major event, usually a disaster!

Comets are sometimes visible for whole weeks. They appear to move slowly through the sky although, in fact, their speed is very great. They are rarely visible to the naked eye.
The most famous is Halley's Comet. It is named after an English astronomer who saw a very visible comet in 1682 and predicted that it would reappear in 1758. It makes an orbit of the sun every 76 years, and last appeared in 1986. It will return in 2062. Let's hope it will be on time!