What is unique about Halley's Comet?

Halley didn't live to see the comet's return, but his discovery led to the comet being named after him. (The traditional pronunciation of the name usually rhymes with valley.) Halley's calculations showed that at least some comets orbit the sun. read more

Halley is almost unique among comets in that it is both large and active and has a well defined, regular orbit. read more

Halley's Comet is shaped like a peanut and is about 15 kilometres (9 miles) long, and 8 kilometres (5 miles) wide and thick. Fact Nine. American writer Mark Twain was born on November 30th 1835, two weeks after an appearance of Halley's Comet's. In his biography, he stated that he was born with Halley's Comet, and is likely to die with it. read more