mirrored file at http://SaturnianCosmology.Org/ For complete access to all the files of this collection see http://SaturnianCosmology.org/search.php ========================================================== ___________________________________ Uranus Fact Sheet ___________________________________ [1][Voyager 2 image of Uranus] _________________________________________________________________ Uranus/Earth Comparison _________________________________________________________________ Bulk parameters Uranus Earth Ratio (Uranus/Earth) Mass (10^24 kg) 86.832 5.9736 14.536 Volume (10^10 km^3) 6,833 108.321 63.08 Radius (1 bar level) (km) Equatorial 25,559 6,378.1 4.007 Polar 24,973 6,356.8 3.929 Volumetric mean radius (km) 25,362 6,371.0 3.981 Ellipticity (Flattening) 0.02293 0.00335 6.84 Mean density (kg/m^3) 1,270 5,515 0.230 Gravity (eq., 1 bar) (m/s^2) 8.87 9.80 0.905 Acceleration (eq., 1 bar) (m/s^2) 8.69 9.78 0.889 Escape velocity (km/s) 21.3 11.19 1.903 GM (x 10^6 km^3/s^2) 5.794 0.3986 14.536 Bond albedo 0.300 0.306 0.980 Visual geometric albedo 0.51 0.367 1.390 Visual magnitude V(1,0) -7.19 -3.86 - Solar irradiance (W/m^2) 3.71 1,367.6 0.0027 Black-body temperature (K) 58.2 254.3 0.229 Moment of inertia (I/MR^2) 0.225 0.3308 0.680 J[2] (x 10^-6) 3343.43 1082.63 3.088 Number of natural satellites 26 1 Planetary ring system Yes No _________________________________________________________________ Orbital parameters Uranus Earth Ratio (Uranus/Earth) Semimajor axis (10^6 km) 2,872.46 149.60 19.201 Sidereal orbit period (days) 30,685.4 365.256 84.011 Tropical orbit period (days) 30,588.740 365.242 83.749 Perihelion (10^6 km) 2,741.30 147.09 18.637 Aphelion (10^6 km) 3,003.62 152.10 19.748 Synodic period (days) 369.66 - - Mean orbital velocity (km/s) 6.81 29.78 0.229 Max. orbital velocity (km/s) 7.11 30.29 0.235 Min. orbital velocity (km/s) 6.49 29.29 0.222 Orbit inclination (deg) 0.772 0.000 - Orbit eccentricity 0.0457 0.0167 2.737 Sidereal rotation period (hours) -17.24* 23.9345 0.720 Length of day (hrs) 17.24 24.0000 0.718 Obliquity to orbit (deg) 97.77 23.45 4.169 * Magnetic coordinates (as determined by the Voyager 2 Radio Science experiment) _________________________________________________________________ Uranus Observational Parameters Discoverer: William Herschel Discovery Date: 13 March 1781 Distance from Earth Minimum (10^6 km) 2581.9 Maximum (10^6 km) 3157.3 Apparent diameter from Earth Maximum (seconds of arc) 4.1 Minimum (seconds of arc) 3.3 Mean values at opposition from Earth Distance from Earth (10^6 km) 2719.99 Apparent diameter (seconds of arc) 3.9 Apparent visual magnitude 5.5 Maximum apparent visual magnitude 5.32 Uranus Mean Orbital Elements (J2000) Semimajor axis (AU) 19.19126393 Orbital eccentricity 0.04716771 Orbital inclination (deg) 0.76986 Longitude of ascending node (deg) 74.22988 Longitude of perihelion (deg) 170.96424 Mean Longitude (deg) 313.23218 _________________________________________________________________ North Pole of Rotation Right Ascension: 257.43 Declination : -15.10 Reference Date : 12:00 UT 1 Jan 2000 (JD 2451545.0) _________________________________________________________________ Uranian Magnetosphere Dipole field strength: 0.228 gauss-Ru^3 Dipole tilt to rotational axis: 58.6 degrees Dipole offset (planet center to dipole center) distance: 0.3 Ru along the rotat ion axis Note: Ru denotes Uranian radii, here defined to be 25,600 km _________________________________________________________________ Uranian Atmosphere Surface Pressure: >>1000 bars Temperature at 1 bar: 76 K (-197 C) Temperature at 0.1 bar: 53 K (-220 C) Density at 1 bar: 0.42 kg/m^3 Wind speeds: 0-200 m/s Scale height: 27.7 km Mean molecular weight: 2.64 g/mole Atmospheric composition (by volume, uncertainty in parentheses) Major: Molecular hydrogen (H[2]) - 82.5% (3.3%); Helium (He) - 15.2% (3.3%) Methane (CH[4]) - 2.3% Minor (ppm): Hydrogen Deuteride (HD) - 148 Aerosols: Ammonia ice, water ice, ammonia hydrosulfide, methane ice(?) _________________________________________________________________ [2]bullet Uranian Satellite Fact Sheet [3]bullet Uranian Rings Fact Sheet [4]bullet Planetary Fact Table - metric units [5]bullet Planetary Fact Table - U.S. units [6]bullet Planetary Fact Table - Earth ratio [7]bullet Uranus Home Page [8]bullet Directory to other Planetary Fact Sheets [9]bullet NSSDC Planetary Home Page _________________________________________________________________ If no sub- or superscripts appear on this page - for example, if the "Mass" is given in units of "(1024 kg)" - you may want to check the [10]notes on the sub- and superscripts. [11]bullet Notes on the factsheets - definitions of parameters, units, notes on sub- and superscripts, etc. _________________________________________________________________ Questions and comments about this page should be addressed to: Dr. David R. Williams, [12]dwilliam at nssdc.gsfc.nasa.gov, +1-301-286-1258 NSSDC, Mail Code 633, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 or Dr. Edwin V. Bell II, [13]ed.bell at gsfc.nasa.gov, +1-301-286-1187 NSSDC, Mail Code 633, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 [NSSDC logo] _________________________________________________________________ NASA Official: Ed Grayzeck, edwin.j.grayzeck at nasa.gov Last Updated: 19 May 2004, DRW References 1. http://nssdc.gsfc.nasa.gov/planetary/image/uranus_voy2.jpg 2. http://nssdc.gsfc.nasa.gov/planetary/factsheet/uraniansatfact.html 3. http://nssdc.gsfc.nasa.gov/planetary/factsheet/uranringfact.html 4. http://nssdc.gsfc.nasa.gov/planetary/factsheet/index.html 5. http://nssdc.gsfc.nasa.gov/planetary/factsheet/planet_table_british.html 6. http://nssdc.gsfc.nasa.gov/planetary/factsheet/planet_table_ratio.html 7. http://nssdc.gsfc.nasa.gov/planetary/planets/uranuspage.html 8. http://nssdc.gsfc.nasa.gov/planetary/planetfact.html 9. http://nssdc.gsfc.nasa.gov/planetary/planetary_home.html 10. http://nssdc.gsfc.nasa.gov/planetary/factsheet/fact_notes.html 11. http://nssdc.gsfc.nasa.gov/planetary/factsheet/fact_notes.html 12. mailto:dwilliam at nssdc.gsfc.nasa.gov 13. mailto:ed.bell at gsfc.nasa.gov