Planets - Data Table

Dwarf Planets are listed in a separate table below.

Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune
diameter (Earth=1) 0.382 0.949 1 0.532 11.209 9.44 4.007 3.883
diameter (km) 4,878 12,104 12,756 6,787 142,800 120,000 51,118 49,528
mass (Earth=1) 0.055 0.815 1 0.107 318 95 15 17
mean distance from Sun (AU) 0.39 0.72 1 1.52 5.20 9.54 19.18 30.06
orbital period (Earth years) 0.24 0.62 1 1.88 11.86 29.46 84.01 164.8
orbital eccentricity 0.2056 0.0068 0.0167 0.0934 0.0483 0.0560 0.0461 0.0097
mean orbital velocity (km/sec) 47.89 35.03 29.79 24.13 13.06 9.64 6.81 5.43
rotation period (in Earth days) 58.65 -243* 1 1.03 0.41 0.44 -0.72* 0.72
inclination of axis (degrees) 0.0 177.4 23.45 23.98 3.08 26.73 97.92 28.8
mean temperature at surface (C) -180 to 430 465 -89 to 58 -82 to 0 -150 -170 -200 -210
gravity at equator (Earth=1) 0.38 0.9 1 0.38 2.64 0.93 0.89 1.12
escape velocity (km/sec) 4.25 10.36 11.18 5.02 59.54 35.49 21.29 23.71
mean density (water=1) 5.43 5.25 5.52 3.93 1.33 0.71 1.24 1.67
atmospheric composition none CO2 N2 + O2 CO2 H2+He H2+He H2+He H2+He
number of moons
rings? no no no no yes yes yes yes

Dwarf Planets

Ceres Pluto Haumea Makemake Eris
diameter (Earth=1) 0.076 0.180 0.110
(average)		 0.102-0.149 0.188-0.235
diameter (km) 974.6 2,300 1,960 x 1,518 x 996
(ellipsoid)		 1,300-1,900 2,400-3,000
mass (Earth=1) 0.00016 0.002 0.00070 0.00067 0.0028
mean distance from Sun (AU) 2.76596 39.44 43.335 45.791 67.6681
orbital period (Earth years) 4.599 247.7 285.4 309.88 557
orbital eccentricity 0.07976 0.2482 0.18874 0.159 0.44177
mean orbital velocity (km/sec) 17.882 4.74 4.484 4.419 3.436
rotation period (in Earth days) 0.378 -6.38* 0.163 ? > 8 hrs ?
inclination of axis (degrees) 3 122 ? ? ?
mean temperature at surface (°C) -106 -220 -223 -240 -230
gravity at equator (Earth=1) 0.028 0.06 0.045 0.051 0.082
escape velocity (km/sec) 0.51 1.27 0.84 0.8 1.31
mean density (water=1) 2.077 2.03 2.6-3.3 2 1.18-2.31
atmospheric composition none CH4 none? maybe CH4 maybe CH4
number of moons
rings? no no no no no
* Negative values of rotation period indicate that the planet rotates in the direction opposite to that in which it orbits the Sun. This is called retrograde rotation.

The eccentricity (e) is a number which measures how elliptical orbits are. If e=0, the orbit is a circle. All the planets have eccentricities close to 0, so they must have orbits which are nearly circular.

Last modified October 9, 2008 by Randy Russell.

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