A comet is an object in space that around the sun. People first thought that they were only strange changes of but Newton proved that they were planets with .
A comet is made up of an inner part called and a cloud around it made up of ice, and other gases. Scientists call it a dirty .
When a comet the sun, the icy parts and the comet gets brighter and brighter. The tail of a comet , which always points away from the sun, can into space for millions of km. Some comets have short tails, so that they are almost .
Comets have orbits and they appear at different intervals. Some of them every 3 or 4 years and others have periods of 2,000 years and more.