What Are Comets?

Comets are basically dirty snowballs - mixtures of ice, dust, and rocky material. When they get close to the sun, the ice vaporizes and creates that beautiful tail that points away from the sun.

Famous Comets

Halley's Comet is probably the most famous - it returns to Earth every about 76 years. The last time was 1986, so we're due for another appearance soon!