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 Automatic translation  Automatic translation Category: Planets and dwarf planets
Updated June 01, 2013

Uranus is barely visible to the naked eye in very clear night, it appears, even with powerful tools that as a small greenish disk. Uranus is the seventh planet of the solar system, a gas giant and the third in size. The blue-green coloration results from the absorption bands of methane. Its appearance reflects the presence of a high-altitude hydrocarbon photochemical haze overlying clouds of methane, which in turn overlie clouds of hydrogen sulfide and/or ammonia. Uranus was discovered March 13, 1781 by William Herschel. Uranus is 3 times smaller than Jupiter. Named comes from the god Uranus, Roman god of the sky, equivalent to the Greek god Ouranos.
Uranus has a rotation axis tilted at 98° (The Earth is 23.27 °, and that of Jupiter of 3.22 °). Uranus is almost lying on its orbit. Uranus is a gas giant planet, like Jupiter, Saturn and Neptune. In theory, it would consist of a solid core of iron and silicates of about 7 500 km in diameter, surrounded by a mantle composed of molecular hydrogen, helium, methane and ammonia on a thickness of 10 000 km, then a surface layer of liquid hydrogen and helium, thickness of about 7 600 km merges gradually into the atmosphere. Unlike Jupiter and Saturn, Uranus is not massive enough that hydrogen exists in the metallic state around the core.

 planet uranus 
Uranus Characteristics
Aphelion 3 004 419 704 km
Perihelion 2 748 938 461 km
Eccentricity 0.044405
Orbital period 30 799.095 days
 or 84.323 326 years
Mass 8.686x1025 kg
(14.5 times the earth)
Equatorial diameter 51 118 km
Polar diameter 49 946 km
Inclination of the axis 97.77°
Discovered by William Herschel
Circumference 17 620 000 000 km
Volume 69.142 x 1012 km3
Albedo 0.51
Escape velocity 21.3 km/s
Inclination to the ecliptic 0.772556° to Ecliptic

Image: Photograph of Uranus, its rings and its moons taken by Hubble. (Image credit NASA). You can see on this picture, 10 moons of Uranus.

The seventh planet


"A planet is a celestial body that is in orbit around the Sun, which has sufficient mass for its gravity to overcome the cohesive forces of the solid body and maintain hydrostatic equilibrium (spherical), and that eliminated any body moving in an orbit close ".
This definition was approved August 24, 2006, at the 26th General Assembly of the IAU (International Astronomical Union) by a show of hands of about 400 scientists and astronomers after ten days of discussions. This is Friedrich Wilhelm Herschel who discovered Uranus by accident March 13, 1781 and he thinks at first to deal with a comet. Uranus had been observed before but it was ignored, and cataloged as simply another star (the first recorded sighting of Uranus date in 1690 when John Flamsteed cataloged it as 34 Tauri star). Having correctly identified the nature of the star, Herschel called the Georgian Planet in honor of King George III of England. The name Uranus was first proposed by Johan Elert Bode in conformity with the names of other planets and admitted until 1850. Uranus showed irregularities in its orbit around the Sun that could explain the law of universal gravitation.


He had an eighth planet to explain these irregularities. A lock psychological jumped, the dimensions of the solar system at once doubled.
Most planets spin on an axis nearly perpendicular to the plane of the ecliptic but Uranus' axis is almost parallel to that plane.
Uranus' atmosphere is constituted of about 83% hydrogen, 15% helium and 2.3% methane.
Uranus is composed of a solid core and iron silicate of about 7500 km in diameter, surrounded by a coat composed of ice water mixed with helium, methane and ammonia to a thickness 10 000 km, then a surface layer of liquid hydrogen and helium, thickness of about 7600 km.
Uranus' blue color is the result of absorption of red light by methane in the upper atmosphere. Uranus has rings like other gas giant, its rings were not discovered until 1979. They are very dark as those of Jupiter and composed of relatively large particles, up to 10 meters in diameter in addition to fine dust, like the rings of Saturn. There are 11 known rings, all very low, the brightest being the epsilon ring.


Aurora on Uranus


Uranus is unique in the solar system because the inclination of its axis of rotation is about 98°, i.e. it is practically lying on the plane of revolution around the Sun. The geographic poles face the sun while on the other planets they are perpendicular to the plane of rotation. Solar flares also reach Uranus, this is how the astronomer Laurent Lamy, of the Paris Observatory, observed the aurora on Uranus.
Thanks to the Hubble Space Telescope has obtained the magnificent image of the distant Uranus.
The aurora of Uranus appeared on these two images as point light sources and not as large as arcs on other planets. A few days apart, the space telescope has captured the appearance of auroras at the poles of the magnetic field of the giant planet.
The magnetic poles of the planet are located at 60° of its geographic poles.


Image: Aurora on Uranus photographed in November 2011 by the Hubble Space Telescope.
© Nasa/Observatoire de Paris/NASA/ESA/HST

 Aurora on Uranus

The names of the moons of Uranus

Diameter (km)Masse
Discovered byCommentDate
Titania 436 00015783.49×1021HerschelQueen of the Fairies in Dream of a Summer Night by Shakespeare 1787
Oberon583 00015233.03×1021HerschelKing of the Fairies in in the dream of a summer night of Shakespeare 1787
Umbriel 266 000 1170 1.27×1021 Lassel Character of The Rape of the Lock (The lock of hair stolen) by Alexander Pope 1851
Ariel 191 000 1158 1,35×1021 Lassel Genie air in the room the storm of Shakespeare 1851
Miranda 130 000 472 6,6×1019 Gérard P.Kuiper Daughter of the magician Prospero in Shakespeare's play Storm 1948
Sycorax 12 179 000 190 5,4×1018 Philip D.Nicholson Mother of the monster Caliban in Shakespeare's play Storm 1997
Puck86 0001622,89×1018Voyager 2Evil spirit in the room the Dream of a Summer Night by Shakespeare 1985
Portia 66 000 135 1,68×1018 Voyager 2 Rich heiress in the theater play The Merchant of Venice Shakespeare 1986
Caliban 7 231 000 98 7,3×1017 Brett J. Gladman Monster in the room the storm of Shakespeare 1997
Juliet 64 000 93 5,57×1017 Voyager 2 Tragic heroine of the theater play Romeo and Juliet 1986
Belinda 75 000 80 3,57×1017 Voyager 2 Heroine of the loop flight of Alexander Pope 1986
Cressida 62 000803,43×1017Voyager 2Daughter of Calchas in Shakespeare's Troilus and Cressida 1986
Rosalind 70 000 72 2,54×1017 Voyager 2 Daughter of the Duke proscribed in the theater play As You Like It by Shakespeare 1986
Desdemona 63 000 64 1,78×1017 Voyager 2 Wife of Othello in the theater play Shakespeare's Othello 1986
Bianca 59 000 51 9,3×1016 Voyager 2 Sister of Katherine in the theater play of Shakespeare's Taming of the Shrew 1986
Ophelia54 000425,4×1016Voyager 2Daughter of Polonius in the theater play Hamlet by Shakespeare 1986
Cordelia 50 000 40 4,5×1016 Voyager 2 Daughter of King Lear in the theater play King Lear by Shakespeare 1986
Prospero 16 256 000 30 2,1×1016 Matthew Holman Sorcerer, Duke of Milan in the room the storm of Shakespeare 1999
Setebos17 418 000302,1×1016John J.KavelaarsGod worshiped by Caliban and Sycorax in Shakespeare's play Storm 1999
Stephano8 004 000206×1015Brett J. GladmanAlcoholic majordomo in the play Shakespeare Storm 1999
Perdita 76 420 20  Erich Karkoschka Character of the play The Winter's Tale Shakespeare. 1999
Francisco 4 276 000 12  Brett J. Gladman Character in the play Shakespeare Storm 2003
Ferdinand 20 901 000 12   Character in the play Shakespeare Storm 2001
Margaret 14 345 000 11  Matthew Holman Servant of Hero in the play, Much Ado About Nothing by Shakespeare 2003
Cupid 74 800 10  Mark Showalter Character in the play Shakespeare's Timon of Athens 2003
Mab 97 734 10  Mark Showalter Fairy mentioned in the theater play Romeo and Juliet 2003
Trinculo 8 504 000 10  Matthew Holman Buffoon in the Shakespeare play Storm 2001
1997 © − Astronomy, Astrophysics, Evolution and Earth science.
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