Halleies

Halleies, also known as Halleys, are a type of comet that are named after the English astronomer Edmond Halley. These comets are characterized by their periodic orbits around the Sun, typically taking between 75 to 76 years to complete one orbit. The most famous Halley's comet is Comet Halley, which is visible from Earth approximately every 75-76 years. The last time Comet Halley was visible from Earth was in 1986, and it is expected to be visible again in 2061.

Halley's comets are believed to originate from the Oort cloud, a region of space beyond the orbit of Neptune that is thought to contain trillions of comets. When a Halley's comet approaches the Sun, the heat causes the comet's icy nucleus to vaporize, creating a glowing coma and a long tail that can stretch for millions of kilometers. The tail of a Halley's comet always points away from the Sun due to the solar wind.

Halley's comets are of particular interest to astronomers because they provide valuable information about the composition of the early solar system. The study of Halley's comets has also led to the development of new technologies and techniques for observing and studying comets. In addition, the appearance of a Halley's comet is often considered a significant event, with many cultures and societies associating it with omens and prophecies.