Halley's Comet or
Comet Halley ( or ), officially designated
1P/Halley, is a
short-period comet visible from
Earth every 75–76 years. Halley is the only known short-period
comet that is clearly visible to the
naked eye from Earth, and the only naked-eye comet that might appear twice in a human lifetime. Halley last appeared in the inner parts of the
Solar System in 1986 and will next appear in mid-2061.