Halley's Comet is a short-period comet visible from Earth every 75–76 years. It is the only known short-period comet that is regularly visible to the naked eye from Earth. It has been observed and recorded by astronomers since at least 240 BC.
The Kuiper Belt is a circumstellar disc in the outer Solar System, extending beyond the orbit of Neptune. It is similar to the asteroid belt, but is far larger and composed largely of frozen volatiles.