A once in a lifetime event visible every 75-76 years, Halleys comet returned in 1986. Halley is the only short-period comet that is clearly visible to the naked eye from Earth. It has been documented since 240 BC.

A once in a lifetime event visible every 75-76 years, Halleys comet returned in 1986. Halley is the only short-period comet that is clearly visible to the naked eye from Earth. It has been documented since 240 BC.