Glossary term: Halley's Comet
Description: Halley's comet is, arguably, the most famous comet because it is the only short-cycle comet visible to the naked eye from Earth with a period short enough (about 75 years) to potentially allow people to see it twice in their lives. The comet's last visit was in 1986, and it is expected to return in 2061. It is named after the English astronomer Edmond Halley who was the first to calculate its periodicity and predict its next visit. Halley noticed that the comets that appeared in the years 1531, 1607, and 1682 all had very similar orbits and thus were all visits of the same comet to the inner Solar System. He correctly predicted the comet's return in 1758.
It has been visited by the Vega and Giotto space missions. These found that the comet's dust consists mainly of silicates, iron, and magnesium, in addition to carbon–hydrogen–oxygen–nitrogen compounds (CHON). The comet's nucleus is made mostly of ice.
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Term and definition status: This term and its definition have been approved by a research astronomer and a teacher
The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".
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In Other Languages
- Arabic: مذنب هالي
- German: Halleyscher Komet
- Spanish: El Cometa Halley
- French: La comète de Halley
- Italian: La cometa di Halley
- Japanese: ハレー彗星 (external link)
- Brazilian Portuguese: Cometa Halley
- Simplified Chinese: 哈雷彗星
- Traditional Chinese: 哈雷彗星
Related Media
Halley's Comet
Caption: Halley’s Comet, is a well-known periodic comet, named after the English astronomer Edmond Halley. It has an orbital period of approximately 75 years and is visible from Earth with the naked eye when it passes through the inner solar system.
The image shows Halley’s Comet, officially designated 1P/Halley, with a tail of gas and dust streaming away from the Sun. It was taken from the La-Silla-Observatory in Chile in 1986 during Halley's Comet's last visit to the inner solar system. The stars in this image appear elongated or as lines of three different colored dots as image was created from three separate observations in different colors of light and the telescope was tracking the comet, which was moving very slightly compared to the background stars. Note that the comets tail does not point in exactly the same direction as the elongation of the stars. This shows us that the comet tail is not always behind the comet, but instead pointing away from the Sun.
The comet passes its perihelion (closest distance to the Sun) at a distance of around 0.59 astronomical units, right between the orbits of Mercury and Venus. Beyond Neptune, it reaches its aphelion (furthest distance from the Sun) at a distance of approximately 35 astronomical units. Halley's Comet reached aphelion in December 2023 and is now moving inwards again. It is expected to be seen with the naked eye from Earth again in mid-2061.
Credit: ESO
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