1P/ Halley

                                 1P/Halley

Halley's Comet is designated as 1P/Halley, is a short-period comet visible from Earth every 75–79 years. Halley is the only known short-period comet that is regularly visible to the naked eye from Earth, and this comet can appear only twice in a human lifetime. Halley is often called the most famous comet. Astronomers have now linked the comet's appearances to observations dating back more than 2,000 years. Halley was last seen in Earth's skies in 1986. It will return in 2061.Halley's comet was recorded by Edmund Halley in 1682. It was seen again in 1758, 1835, 1910, and 1986.Since the mass of the comet is 2.24 ×1014 × 10 14 kg and that of Earth is 5.97×1024 5.97 × 10 24, mass of the Earth is around 30 billion times that of Halley's comet. This makes sense because the density of Earth is much greater than a comet, which is like a dirty snowball. Like all comets that take less than about 200 years to orbit the Sun, Halley's Comet is believed to have originated from the Kuiper Belt. Halley's orbital period over the last 3 centuries has been between 75–76 years, although it has varied between 74–79 years since 240 BC. Its orbit around the Sun is highly elliptical.

History of Halley's Comet

Until the time of English astronomer Edmond Halley (1656-1742), comets were believed to make only one pass through the solar system. But in 1705, Halley used Isaac Newton's theories of gravitation and planetary motions to compute the orbits of several comets. Halley found the similarities in the orbits of bright comets reported in 1531, 1607, and 1682 and he suggested that the trio was actually a single comet making return trips. Halley correctly predicted the comet would return in 1758. History's first known "periodic" comet was later named in his honor.

Meteor Showers

Each time Halley returns to the inner solar system its nucleus sprays ice and rock into space. This debris stream results in two weak meteor showers each year.

Size

Halley's dimensions are about 9.3 by 5 miles (15 kilometers by 8 kilometers). It is one of the darkest, or least reflective, objects in the solar system. It has an albedo of 0.03, which means that it reflects only 3% of the light that falls on it.

Lifetime

With each orbit around the Sun, a comet the size of Halley loses an estimated 3 to 10 feet (1 to 3 meters) of material from the surface of its nucleus. Thus, as the comet ages, it eventually dims in appearance and may lose all the ices in its nucleus. The tails disappear at that stage, and the comet finally evolves into a dark mass of rocky material or perhaps dissipates into dust. Scientists calculate that an average periodic comet lives to complete about 1,000 trips around the Sun. Halley has been in its present orbit for at least 16,000 years, but it has shown no obvious signs of aging in its recorded appearances.

How Comet 1P/Halley Got Its Name

With each orbit around the Sun, a comet the size of Halley loses an estimated 3 to 10 feet (1 to 3 meters) of material from the surface of its nucleus. Thus, as the comet ages, it eventually dims in appearance and may lose all the ices in its nucleus. The tails disappear at that stage, and the comet finally evolves into a dark mass of rocky material or perhaps dissipates into dust. Scientists calculate that an average periodic comet lives to complete about 1,000 trips around the Sun. Halley has been in its present orbit for at least 16,000 years, but it has shown no obvious signs of aging in its recorded appearances.

Conclusion

Halley’s Comet returns to earth after every 75 years and is next expected to be seen in the year 2061. It also has an ionized tail which is called the coma. The coma is formed when the comet comes closer to the sun. It has been created with the help of ice and matter, which had been left over after the solar system’s formation. With an orbital period of 20 years, it revolves around the sun in the opposite direction as the other planets in the solar system. It is not a very large comet, although it is large enough to be detected by people.

Purva A