Comet Hale–Bopp (formally designated is a comet that was perhaps the most widely observed of the century and one of the brightest seen for many decades. It was visible to the naked eye for a record 18 months. The comet was dubbed the Great Comet of
Halley's Comet It came by the Earth last in and will return in Halley's comet orbits Earth every 76 years. Of the thousands of known comets in the solar system, Halley's comet is one of some 200 that are periodic.