Uranus, as seen by Voyager 2
|Discovered by||William Herschel|
|Discovery date||March 13, 1781|
|Aphelion||3 004 419 704 km
20.083 305 26 AU
|Perihelion||2 748 938 461 km
18.375 518 63 AU
|Semi-major axis||2 876 679 082 km
19.229 411 95 AU
|Eccentricity||0.044 405 586|
|Orbital period||30 799.095 days
84.323 326 yr
|Synodic period||369.66 days|
|Average orbital speed||6.81 km/s|
|Mean anomaly||142.955 717°|
6.48° to Sun's equator
|Longitude of ascending node||73.989 821°|
|Argument of perihelion||96.541 318°|
|Equatorial radius||25 559 ± 4 km
|Polar radius||24 973 ± 20 km
|Flattening||0.022 9 ± 0.000 8[b]|
|Surface area||8.115 6×109 km²[c]
|Mass||GM=5 793 939 ± 13 km³/s²|
|Mean density||1.27 g/cm³[c]|
|Equatorial surface gravity||8.69 m/s²[c]
|Escape velocity||21.3 km/s|
|Sidereal rotation period||−0.718 33 day
17 h 14 min 24 s
|Equatorial rotation velocity||2.59 km/s
|North pole right ascension||17 h 9 min 15 s
|North pole declination||−15.175°|
Uranus is the seventh planet from the Sun in the Solar System. It is a gas giant. It is the third largest planet in the solar system. The planet is made of ice, gases and liquid metal. Its atmosphere contains hydrogen, helium and methane. The temperature on Uranus is −197 degrees C (79 K). The planet is tilted on its axis so much that it is sideways.
This planet can be seen with the naked eye under perfect conditions. Some evidence suggests that this planet was catalogued as a star (34 Tauri) before its confirmed discovery.[source?]
Uranus is covered in blue clouds. The clouds, made of methane, are difficult to see as they are low in the atmosphere. There are also violent storms on the surface with winds that blow at 160 miles per hour. Scientists are studying the clouds to try and understand the storms on the planet.
The planet Uranus has a system made of 13 rings between the more extensive set around Saturn and the simpler systems around Jupiter and Neptune. The rings of Uranus were discovered on March 10, 1977, by James L. Elliot, Edward W. Dunham, and Douglas J. Mink. More than 200 years ago, William Herschel also reported observing rings, but modern astronomers do not believe that he saw them, because they are very dark and faint. Two additional rings were discovered in 1986 in images taken by the Voyager 2, and two outer rings were found in 2003–2005 by the Hubble Space Telescope. As of 2010 people know that the Uranian ring system have 13 rings. In the order of increasing distance from the planet they were called 1986U2R/ζ, 6, 5, 4, α, β, η, γ, δ, λ, ε, ν and μ. They are probably composed of water
The rings of Uranus are thought to be relatively young, not more than 600 million years old. The Uranian ring system probably began from the collisional fragmentation of moons that once existed around the planet. After colliding, the moons probably broke up into many particles, which survived as narrow and optically dense rings only in strictly confined zones of maximum stability.
General properties [change]
As we know currently, the ring system of Uranus has thirteen distinct rings. In order of increasing distance from the planet they are: 1986U2R/ζ, 6, 5, 4, α, β, η, γ, δ, λ, ε, ν, μ rings. They can be divided into three groups: nine narrow main rings (6, 5, 4, α, β, η, γ, δ, ε), two dusty rings (1986U2R/ζ, λ) and two outer rings (μ, ν). The rings of Uranus consist mainly of macroscopic particles and little dust, although dust is known to be present in 1986U2R/ζ, η, δ, λ, ν and μ rings. In addition to these well-known rings, there may be numerous optically thin dust bands and faint rings between them. These faint rings and dust bands may exist only temporarily or consist of a number of separate arcs, which are sometimes detected during occultations. Some of them became visible during a series of ring plane-crossing events in 2007. A number of dust bands between the rings were observed in forward-scattering[a] geometry by Voyager 2. All rings of Uranus show azimuthal brightness variations.
The rings are made of an extremely dark material. The rings are slightly red in the ultraviolet and visible parts of the spectrum and grey in near-infrared. They exhibit no identifiable spectral features. The chemical composition of the ring particles is not known. However, they cannot be made of pure water ice like the rings of Saturn because they are too dark, darker than the inner moons of Uranus. This indicates that they are probably composed of a mixture of the ice and a dark material. The nature of this material is not clear, but it may be organic compounds considerably darkened by the charged particle irradiation from the Uranian magnetosphere. The rings' particles may consist of a heavily processed material which was initially similar to that of the inner moons.
As a whole, the ring system of Uranus is unlike either the faint dusty rings of Jupiter or the broad and complex rings of Saturn, some of which are composed of very bright material—water ice. However, there are similarities with some parts of the latter ring system; the Saturnian F ring and the ε ring are both narrow, relatively dark and are shepherded by a pair of moons. The newly discovered outer rings of Uranus are similar to the outer G and E rings of Saturn. Narrow ringlets existing in the broad Saturnian rings also resemble the narrow rings of Uranus. In addition, dust bands observed between the main rings of Uranus may be similar to the rings of Jupiter. In contrast, the Neptunian ring system is quite similar to that of Uranus, although it is less complex, darker and contains more dust; the Neptunian rings are also positioned further from the planet.
Other pages [change]
- Williams, Dr. David R. (January 31, 2005). "Uranus Fact Sheet". NASA. http://nssdc.gsfc.nasa.gov/planetary/factsheet/uranusfact.html. Retrieved 2007-08-10.
- Yeomans, Donald K. (July 13, 2006). "HORIZONS System". NASA JPL. http://ssd.jpl.nasa.gov/?horizons. Retrieved 2007-08-08. — At the site, go to the "web interface" then select "Ephemeris Type: ELEMENTS", "Target Body: Uranus Barycenter" and "Center: Sun".
- Seidelmann, P. Kenneth; Archinal, B. A.; A’hearn, M. F.; et al. (2007). "Report of the IAU/IAGWorking Group on cartographic coordinates and rotational elements: 2006". Celestial Mech. Dyn. Astr. 90: 155–180. doi:10.1007/s10569-007-9072-y. http://adsabs.harvard.edu/doi/10.1007/s10569-007-9072-y.
- Munsell, Kirk (May 14, 2007). "NASA: Solar System Exploration: Planets: Uranus: Facts & Figures". NASA. http://solarsystem.nasa.gov/planets/profile.cfm?Object=Uranus&Display=Facts. Retrieved 2007-08-13.
- Jacobson, R.A.; Campbell, J.K.; Taylor, A.H.; Synnott, S.P. (1992). "The masses of Uranus and its major satellites from Voyager tracking data and Earth-based Uranian satellite data". The Astronomical Journal 103 (6): 2068–2078. doi:10.1086/116211. http://adsabs.harvard.edu/abs/1992AJ....103.2068J.
- Fred Espenak (2005). "Twelve Year Planetary Ephemeris: 1995 - 2006". NASA. http://sunearth.gsfc.nasa.gov/eclipse/TYPE/TYPE.html. Retrieved 2007-06-14.
- Gay, Peter; Time-Life Books (1966). "The Practical Philosophers". Age of Enlightenment. Time. pp. 25.
- Faure, Gunter; Mensing, Teresa (2007). "Uranus: What Happened Here?". Introduction to Planetary Science. Ed. Faure, Gunter; Mensing, Teresa M.. Springer Netherlands. DOI:10.1007/978-1-4020-5544-7_18.
- "Uranus". nineplanets.org. http://www.nineplanets.org/uranus.html. Retrieved 2007-07-03.
- "Uranus Clouds, overview". windows.ucar.edu. http://www.windows.ucar.edu/tour/link=/uranus/atmosphere/U_clouds_overview.html. Retrieved 29 March 2010.
- "SPACE.com -- New Images Reveal Clouds on Planet Uranus". space.com. http://www.space.com/scienceastronomy/uranus_images_041110.html. Retrieved 29 March 2010.
- Elliot, J. L.; Dunham, E.; Mink, D. (1977). "The rings of Uranus". Cornell University. http://www.nature.com/nature/journal/v267/n5609/abs/267328a0.html. Retrieved June 9, 2007.
- Smith, B.A.; Soderblom, L.A.; Beebe, A.; et al. (1986). "Voyager 2 in the Uranian System: Imaging Science Results". Science 233 (4759): 97–102. doi:10.1126/science.233.4759.43. PMID 17812889.
- "NASA's Hubble Discovers New Rings and Moons Around Uranus". Hubblesite. 2005. http://hubblesite.org/newscenter/archive/releases/2005/33/. Retrieved June 9, 2007.
- de Pater, Imke; Hammel, H. B.; Showalter, Mark R.; Van Dam, Marcos A. (2007). "The Dark Side of the Rings of Uranus". Science 317 (5846): 1888–1890. doi:10.1126/science.1148103. PMID 17717152. http://adsabs.harvard.edu/abs/2007Sci...317.1888D.
- Baines, Kevin H.; Yanamandra-Fisher, Padmavati A.; Lebofsky, Larry A.; et al. (1998). "Near-Infrared Absolute Photometric Imaging of the Uranian System". Icarus 132: 266–284. doi:10.1006/icar.1998.5894. http://adsabs.harvard.edu/abs/1998Icar..132..266B.
Other websites [change]
- NASA's Uranus fact sheet
- Uranus Profile by NASA's Solar System Exploration
- Keck pictures of Uranus show best view from the ground — Press release with some photographs showing rings, satellites and clouds
- News reports of December 22, 2005 rings and moons discovery
- Planets—Uranus A kid's guide to Uranus.
☾ = moon(s) ∅ = rings
|Mercury||Venus||Earth ☾||Mars ☾|
|Jupiter ☾ ∅||Saturn ☾ ∅||Uranus ☾ ∅||Neptune ☾ ∅|
|Dwarf planets||Ceres||Pluto ☾||Haumea ☾||Makemake|
|Groups and families: Vulcanoids · Near-Earth asteroids · Asteroid belt
Jupiter Trojans · Centaurs · Neptune Trojans · Asteroid moons · Meteoroids · Pallas · Juno · Vesta · Hygiea · Interamnia · Europa
|See also the list of asteroids.|
|Kuiper belt – Plutinos: Orcus · Ixion – Cubewanos: Varuna ·
Quaoar · Huya
|Scattered disc: Sedna|
|Comets||Periodic comets and non-periodic comets
Damocloids · Oort cloud
|See also the list of solar system objects|