Comet Tails
Astrophysicists belive that comets are formed in the Outer Solar System.
When comets pass from the Outer Solar System to the Inner Solar System, a big change occurs. (The Solar System is where the Earth, Sun and 7 planets are.) The warmth of the Sun burns off any unstable material like gases in the comet. Most importantly, it creates a comet tail. The comet tail or "coma" is caused by solar radiation. This solar heat evaporates any remaining water or gases. With the Sun's rays shining on the comet tail, we can see the comat tail from Earth.