Many comets are discovered by amateur astronomers. The most famous comet is Comet Halley. Two other recently-well-known comets were Comet Kohoutek and Comet Hyakutake. Another well-known comet, named Comet ShoemakerLevy-9, was a popular favorite one week in Summer 1994 when it broke apart and smashed into the planet Jupiter. In 1997, there was Comet Hale-Bopp.
Comets affect Earth. For instance, meteor shower sometimes occur as the Earth passes through the orbit of a comet. In fact, some meteor showers occur with regularity. The Perseid meteor shower occurs every year between August 9 and 13 as the Earth passes thru the orbit of Comet Swift-Tuttle. Similarly, Comet Halley is the source of the Orionid shower in October. Comets are brightest to persons looking out from Earth when they are near the Sun, which makes them visible at sunrise or sunset.