Portal:Uranus

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Uranus

A photo of Uranus taken by Voyager 2.

Uranus is the seventh planet from the Sun; it is the third largest and fourth most massive planet in the solar system. Uranus was the first planet discovered in modern times. Though it is visible to the naked eye like the five classical planets, it was never recognised as a planet by ancient observers due to its dimness. Sir William Herschel announced its discovery on March 13, 1781, expanding the known boundaries of the solar system. Uranus' atmosphere, although similar to Jupiter and Saturn in being composed primarily of hydrogen and helium, contains a higher proportion of "ices" such as water, ammonia and methane, along with the usual traces of hydrocarbons. It has the coldest planetary atmosphere in the solar system, with a minimum temperature of 49 K, and has a complex layered cloud structure in which water is thought to make up the lowest clouds, while methane makes up the uppermost layer of clouds. In 1986, images from the Voyager 2 space probe showed Uranus as a virtually featureless planet in visible light without the cloud bands or storms associated with the other giants. The wind speeds on Uranus can reach 250 m/s (560 mph).

More about...Uranus: its history, rings, atmosphere, climate, moons, and its exploration


Selected article

Voyager 2 image of Portia, Cressida and Ophelia
Portia (/ˈpɔrʃə/ POR-shə) is an inner satellite of Uranus. It was discovered from the images taken by Voyager 2 on 1986-01-03. The moon is named after Portia, the heroine of William Shakespeare's play The Merchant of Venice. It is also designated Uranus XII. Portia is the second-largest inner satellite of Uranus after Puck. It heads a group of satellites called Portia Group, which includes Bianca, Cressida, Desdemona, Juliet, Rosalind, Cupid, Belinda and Perdita. These satellites have similar orbits and photometric properties. Little is known about Portia beyond its size of about 140 km, orbit, and geometric albedo of about 0.08.

Selected biography

Gerard Kuiper
Gerard Peter Kuiper (/ˈkpər/; Dutch pronunciation: [ˈkœypər]; born Gerrit Pieter Kuiper December 7, 1905, Harenkarspel (Tuitjenhorn), Netherlands – December 24, 1973, Mexico City) was a Dutch astronomer who became a naturalized citizen of the United States. Kuiper discovered two natural satellites of planets in the solar system, namely Uranus's satellite Miranda and Neptune's satellite Nereid. In addition, he discovered carbon dioxide in the atmosphere of Mars and the existence of a methane-laced atmosphere above Saturn's satellite Titan in 1944.

Topics

Uranus Atmosphere ˑ Climate ˑ Exploration (Voyager 2) ˑ Rings

Moons (Portia ˑ Puck ˑ Miranda ˑ Ariel ˑ Umbriel ˑ Titania ˑ Oberon ˑ Caliban ˑ Sycorax)

Astronomers: William Herschel ˑ William Lassell ˑ Gerard Kuiper ˑ James L. Elliot

See Also: Formation and evolution of the Solar System ˑ Gas Giant ˑ Nebular hypothesis

Bold articles are featured.
Italicized articles are on dwarf planets or major moons.


Selected picture

Image of Uranus by Voyager 2.
Credit: NASA/JPL

A false color image of Uranus obtained by Voyager 2 spacecraft in January 2006.

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