For the last 4.5 billion years Halley's Comet has orbited the Sun. The last time it was visible to the naked eye on Earth was 1986. read more
Halley's Comet or Comet Halley, officially designated 1P/Halley, is a short-period comet visible from Earth every 74–79 years. Halley is the only known short-period comet that is regularly visible to the naked eye from Earth, and the only naked-eye comet that might appear twice in a human lifetime. read more