What is a comet?

• Comets are frozen leftovers from the formation of the solar system composed of dust, rock, and ices. 
• They range from a few miles to tens of miles wide, but as they orbit closer to the Sun, they heat up and spew gases and dust into a glowing head that can be larger than a planet. 
• This material forms a tail that stretches millions of miles.
• There are likely billions of comets orbiting our Sun in the Kuiper Belt and even more distant Oort Cloud.