Halley's Comet, officially designated 1P/Halley and also referred to as Comet Halley after Edmond Halley, is a comet that can be seen every 75-76 years. It is the most famous of all periodic comets. Although in every century many long-period comets appear brighter and more spectacular, Halley is the only short-period comet that is visible to the naked eye, and thus, the only naked-eye comet certain to return within a human lifetime.http://www.astronomytoday.com/astronomy/comets.html Its appearances over the centuries have been noticed to coincide with many notable events in human history, despite the fact that they were not recognized as the same object until the 17th century.
Halley's Comet, I Didn't Know and Snootable Snunshine are three unreleased songs written by Richard Wrighthttp://www.mockingbirdfoundation.org/press/preorder.html (aka Nancy Taube) for the band Phish. All three of them are notable for their extensive vocal harmony.