Mean orbital velocity per second (in millions): 4.2 miles (6.8 km)
Inclination of axis: 97.9░
Orbital eccentricity: 0.047
Orbital inclination: 0.774
Diameter at equator: 31,770 miles
51,118 km
4.007 x Earth's diameter
Oblateness: 0.023
Escape velocity per second: 13.2 miles (21.3 km)
Mean surface temperature: -353 F / -214 C / 59 K (at cloud tops)
Mass: 8.66 x 10^25 kg
(Earth = 1): 14.5
Volume (Earth =1): 67
Density (water = 1): 1.17
Surface gravity: 11.44 m/s^2
(Earth = 1): 1.17
Maximum apparent diameter as seen from Earth (seconds of arc): 3".7
Mean diameter of Sun as seen from the planet: 1' 41"
Number of known satellites: 15
Satellite data
Cordelia
Mean distance from center of planet: 30,746 mi. (49,471 km)
Orbital period: 0.033 days
Orbital eccentricity: very low
Orbital inclination to planet's equator: very low
Diameter: 16 mi. (26 km)
Escape velocity: very low
Magnitude: ù
Maximum apparent diameter as seen from the planet: ù
Ophelia
Mean distance from center of planet: 33,434 mi. (53,796 km)
Orbital period: 0.372 days
Orbital eccentricity: very low
Orbital inclination to planet's equator (degrees): very low
Diameter: 19 mi. (30 km)
Escape velocity: very low
Magnitude: ù
Maximum apparent diameter as seen from the planet :ù
Bianca
Mean distance from center of planet: 36,776 mi. (59,173 km)
Orbital period: 0.431 days
Orbital eccentricity: very low
Orbital inclination to planet's equator: very low
Diameter: 26 mi. (42 km)
Escape velocity: very low
Magnitude: ù
Maximum apparent diameter as seen from the planet: ù
Cressida
Mean distance from center of planet: 38,395 mi. (61,777 km)
Orbital period: 0.463 days
Orbital eccentricity: very low
Orbital inclination to planet's equator: very low
Diameter: 39 mi. (62 km)
Escape velocity: very low
Magnitude: ù
Maximum apparent diameter as seen from the planet: ù
Desdemona
Mean distance from center of planet: 38,953 mi. (61,676 km)
Orbital period: 0.475 days
Orbital eccentricity: very low
Orbital inclination to planet's equator: very low
Diameter: 34 mi. (54 km)
Escape velocity: very low
Magnitude: ù
Maximum apparent diameter as seen from the planet: ù
Juliet
Mean distance from center of planet: 39,995 mi. (64,352 km)
Orbital period: 0.493 days
Orbital eccentricity: very low
Orbital inclination to planet's equator: very low
Diameter: 52 mi. (84 km)
Escape velocity: very low
Magnitude: ù
Maximum apparent diameter as seen from the planet: ù
Portia
Mean distance from center of planet: 41,072 mi. (66,085 km)
Orbital period: 0.513 days
Orbital eccentricity: very low
Orbital inclination to planet's equator: very low
Diameter: 67 mi. (108 km)
Escape velocity: very low
Magnitude: ù
Maximum apparent diameter as seen from the planet: ù
Rosalind
Mean distance from center of planet: 41,604 mi. (69,941 km)
Orbital period: 0.558 days
Orbital eccentricity: very low
Orbital inclination to planet's equator: very low
Diameter: 34 mi. (54 km)
Escape velocity: very low
Magnitude: ù
Maximum apparent diameter as seen from the planet: ù
Belinda
Mean distance from center of planet: 46,773 mi. (75,258 km)
Orbital period: 0.622 days
Orbital eccentricity: very low
Orbital inclination to planet's equator: very low
Diameter: 41 mi. (66 km)
Escape velocity: very low
Magnitude: ù
Maximum apparent diameter as seen from the planet: ù
Puck
Mean distance from center of planet: 53,450 mi. (86,000 km)
Orbital period: 0.762 days
Orbital eccentricity: very low
Orbital inclination to planet's equator (degrees): very low
Diameter: 96 mi. (154 km)
Escape velocity: very low
Magnitude: ù
Maximum apparent diameter as seen from the planet: ù
Miranda
Mean distance from center of planet: 80,423 mi. (129,400 km)
Orbital period: 1.414 days
Orbital eccentricity: 0.017
Orbital inclination to planet's equator: 0.0
Diameter: 293 mi. (472 km)
Escape velocity: 0.3? mph (0.5? kph)
Magnitude: 16.5
Maximum apparent diameter as seen from the planet: 17'54"
Ariel
Mean distance from center of planet: 118,710 mi. (191,000 km)
Orbital period: 2.520 days
Orbital eccentricity: 0.003
Orbital inclination to planet's equator: 0.0
Diameter: 720 mi. (1,158 km)
Escape velocity: 0.8 mph (1.2 kph)
Magnitude: 14.4
Maximum apparent diameter as seen from the planet: 30'54"
Umbriel
Mean distance from center of planet: 165,500 mi. (266,300 km)
Orbital period: 4.144 days
Orbital eccentricity: 0.004
Orbital inclination to planet's equator: 0.0
Diameter: 727 mi. (1,169 km)
Escape velocity: 0.8 mph (1.2 kph)
Magnitude: 15.3
Maximum apparent diameter as seen from the planet: 14'12"
Titania
Mean distance from center of planet: 270,300 mi. (435,000 km)
Orbital period: 8.706 days
Orbital eccentricity: 0.002
Orbital inclination to planet's equator: 0.0
Diameter: 981 mi. (1,578 km)
Escape velocity: 1.0 mph (1.6 kph)
Magnitude: 14.0
Maximum apparent diameter as seen from the planet: 15'00"
Oberon
Mean distance from center of planet: 362,600 mi. (583,500 km)
Orbital period: 13.463 days
Orbital eccentricity: 0.001
Orbital inclination to planet's equator: 0.0
Diameter: 947 mi. (1,523 km)
Escape velocity: 1.0 mph (1.5 kph)
Magnitude: 14.2
Maximum apparent diameter as seen from the planet: 9'48"
Planet composition
Uranus has a rocky core composed of heavy elements, mainly silicon and iron. Above that, an icy mantle of water, methane, and ammonia is topped by an icy "crust" of compressed hydrogen and helium that grades into atmosphere. There are no clear distinctions between the layers and no surface features on the planet.
The equatorial diameter of Uranus is approximately 51,800 km; 5% greater than that of Neptune. Uranus has only 5% of the mass of Jupiter.
[Rick: Here are the composition figures we found. The crust and mantle figures are real approximations.You might want to compare these to figures you have.]
Core=19,000 km in diameter
Mantle =18,000 km thick
Crust = 10,100 km thick
Topography
Uranus has no distinct topographical features.
Atmosphere
Uranus has a cold, hydrogen-rich atmosphere, with strong methane absorportions in the red and near infrared wavelengths. This absorption is what causes the planet's blue-green appearance. Temperatures near the upper atmosphere average -221 C / -366 F / 52░ K and wind speeds average 580 km (360 miles) per hour.
The mean temperature on Uranus is approximately -350░F / -195░ C / 78░ K, with the maximum being -190░F / -105░ C / 167░ K and the minimum -366░F / -204░ C / 70░ K. From Uranus, the Sun would be between 1,000 and 1,300 times brighter than from Earth.
Magnetic fields and gravity
Unlike any other planet, Uranus lies on its side with its poles alternately pointing toward the Sun during orbit. In addition, the planet's magnetic field does not follow the usual north/south orientation. Instead, it is tilted 60░ from vertical and offset from the planet's center, approximately halfway between the center and outer edge of the planet. Researchers theorize that the field is being generated somewhere above the core, where the pressure is so great that liquid hydrogen assumes the electrical properties of a metal.
The surface gravity on Uranus is 1.17.
Orbit and rotation
Though it is not generally considered to be so, the planet's rotation is technically retrograde due to the 98░ axial inclination. The orbital period is 84 years, and recent studies suggest the rotation period to be 23.9 hours. However, the lack of visible surface features makes it difficult to measure precisely.
Moons and/or rings
For many years, there were only five known satellites: Titania, Oberon, Umbrial, Ariel, and Miranda. All are half rock, half ice satellites between 520 and 1,610 km (323 - 1,000 miles) across. In 1986, Voyager 2 provided proof of the existence of 10 new moons, all between 16 - 169 km (10 - 105 miles) in diameter.
The three brightest moons are Titania, Oberon, and Ariel. Their surfaces are completely covered with ice or frost, making this water the farthest from the Sun known to exist in the solar system. Miranda also features high cliffs, canyons, cratered plains, and winding valleys.
Uranus also features 11 dark rings, which were discovered in 1977 when they occulted a star. They are far less reflective than Saturn's rings, and appear to be composed of dust particles less than 5k in diameter.
Mythology
In Greek mythology, Uranus was the personification of the heaven and ruler of the world. He was also the father of Saturn. Miranda was named for the heroine and Ariel for the benevolent spirit in Shakespeare's play "The Tempest." Umbriel was named for the malevolent spirit in Pope's "Rape of the Lock." Titania was named for the Queen of the fairies and Oberon for the King of the fairies in Shakespeare's "Midsummer Night's Dream."
Discovery and exploration
Uranus was discovered in 1781 by William Herschel, who also discovered the satellites Titania and Oberon (in 1787). William Lassell recovered Umbriel (previously glimpsed by Herschel) and discovered Ariel in 1851. Gerard P. Kuiper discovered Miranda in 1948. Voyager 2 did first close-up survey of Uranus in January 1986.
