Halley's Comet, also known as Comet Halley, is a short-period comet that appears in the inner Solar System every 75 to 76 years. It is one of the most famous and well-studied comets in history, and has been observed by humans since at least 240 BC. The comet is named after English astronomer Edmond Halley, who predicted its return in 1758. Halley's Comet last appeared in the inner Solar System in 1986 and will next appear in 2061.