Halley's Comet

Halley's Comet is a comet of the sol system and is one of the few comets that can be seen by the naked eye when it approaches Earth every 75 to 76 years. Its frequency and easy visibility make it one of the better known comets in the Sol system. On Earth, Halley's Comet is sometimes associated with impending disaster.

Time traveling to 1985, the Cybermen planned to divert Halley's Comet so that it would destroy Earth. This way, the Cyberman home planet of Mondas would not be destroyed when it approached Earth in 1986. They were stopped by the Sixth Doctor. (DW: Attack of the Cybermen, The Tenth Planet'')