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Halley's Comet
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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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Glossary Terms:
Aphelion , Comet , Cometary Tail , Halley's Comet , Perihelion
License: Creative Commons Attribution 4.0 International (CC BY 4.0) Creative Commons Attribution 4.0 International (CC BY 4.0) icons
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An Encounter With Halley's Comet
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Caption: This image shows the solid core, or nucleus, of Halley’s Comet, captured in 1986 by the European Space Agency spacecraft Giotto during its flyby of the comet in the inner Solar System. The nucleus appears irregular and potato-shaped, measuring roughly 15 kilometers (about 9 miles) across, and is composed of a mixture of ice, dust, and rock. Unlike the glowing fuzzy cloud (coma) and long tail that make comets visible from Earth, the nucleus itself is dark and difficult to see until a spacecraft passes close enough to take detailed images.
Halley’s Comet is one of the best-known comets because it returns to the inner Solar System approximately every 76 years, allowing generations of astronomers to observe it repeatedly. The material that is released from the nucleus as the comet warms near the Sun forms a glowing coma and long tails of gas and dust, and over many returns leaves trails of debris that produce meteor showers on Earth, such as the Eta Aquarids in May and the Orionids in October.
Credit: NASA/ESA/Giotto Project
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Glossary Terms:
Cometary Coma , Comet , Comet Nucleus , Halley's Comet
License: Public Domain Public Domain icons
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Comet 67P/Churyumov-Gerasimenko
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Caption: Comet 67P/Churyumov–Gerasimenko's nucleus is a "dirty snowball" made of a mixture of frozen materials and dust. It is shaped like two large lobes: one 4.1 km × 3.3 km × 1.8 km, the other 2.6 km × 2.3 km × 1.8 km. These lobes are connected by a small bridge. When a cometary nucleus such as this nears the Sun its frozen, icy material is heated, turning into gas. This, combined with the embedded dust, provide the material for the comet's characteristic coma and tail.
Credit: ESA/Rosetta/NAVCAM
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Glossary Terms:
Comet , Comet Nucleus
Categories:
Solar System
License: Creative Commons Attribution-ShareAlike 3.0 IGO Creative Commons Attribution-ShareAlike 3.0 IGO icons
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Hello Comet, shall we dance?, by Robert Barsa, Slovakia
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Created for the OAE
Caption: Third place in the 2021 IAU OAE Astrophotography Contest, category Comets.
This beautiful and poetic image taken from Slovakia in July 2020 captures the comet C/2020 F3 (Neowise). The direction of the tails of the comet provides a clue as to the position of the Sun. In the past, the appearance of a comet in the skies could be accompanied by apprehension and even fear from those who did not know what these objects really are. Through careful observations and the applications of knowledge from physics, chemistry and geology, we now understand that comets are objects left over from the earliest days when the Solar System formed. The most distinctive features of a comet are the bluish ion (gas) tail, and whitish dust tail, which can extend for tens of millions of kilometres. These distinctive features, easily observable with the unaided eye together with an understanding of the science, are no longer cause for fear, rather they help us understand the history of our Solar System, and bring awe, joy and contemplation, as portrayed in this image.
Credit: Robert Barsa/IAU OAE
Glossary Terms:
Comet , Cometary Tail
Categories:
Naked Eye Astronomy
, Solar System
License: Creative Commons Attribution 4.0 International (CC BY 4.0) Creative Commons Attribution 4.0 International (CC BY 4.0) icons
This file on Zenodo ( image 2.59 MB)
Comet Hale-Bopp
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Caption: Image of comet C/1995 O1 (Hale-Bopp), taken on 4 April 1997, with an exposure time of 10 minutes. The field shown is about 6.5°x6.5°. Two tails extend from the bright coma: one white-yellowish dust tail and a bluish gas tail, always pointing away from the Sun.
Credit: E. Kolmhofer, H. Raab; Johannes-Kepler-Observatory, Linz, Austria
Credit Link
Glossary Terms:
Comet , Cometary Tail
Categories:
Solar System
License: Creative Commons Attribution-ShareAlike 3.0 Unported Creative Commons Attribution-ShareAlike 3.0 Unported icons
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