Largest moons in the Solar System
(diameter over 1,000 km)
Moon
Planet
Mean
diameter
(km)
Mean distance from centre of planet
(10
3 km)
Orbital
period
(days)
Inclination of orbit (deg.) a
Eccentricity of orbit
Mass
(planet
= 1)
Density
(water = 1)
Geometric
albedo
Ganymede
Jupiter
5262
1070.4
7.155
0.17
0.001
7.80 x 10–5
1.94
0.43
Titan
Saturn
5150 b
1221.9
15.945
0.3
0.029
2.37 x 10–4
1.88
0.2
Callisto
Jupiter
4821
1882.7
16.689
0.19
0.007
5.67 x 10–5
1.83
0.17
Io
Jupiter
3643
421.8
1.769
0.04
0.004
4.70 x 10–5
3.53
0.63
Moon
Earth
3475
384.4
27.322
5.15
0.055
0.0123
3.34
0.12
Europa
Jupiter
3122
671.1
3.551
0.47
0.009
2.53 x 10–5
3.01
0.67
Triton
Neptune
2707
354.76
5.877 (R)
156.87
0.000
2.09 x 10–4
2.06
0.72
Titania
Uranus
1578
436.30
8.706
0.08
0.001
4.06 x 10–5
1.66
0.27
Rhea
Saturn
1529
527.07
4.518
0.33
0.001
4.06 x 10–6
1.23
0.6
Oberon
Uranus
1523
583.50
13.463
0.07
0.001
3.47 x 10–5
1.56
0.23
Iapetus
Saturn
1471
3560.9
79.330
8.31
0.023
3.18 x 10–6
1.08
0.5/0.05
Charon
Pluto
1210
19.57
6.387
96.1
0.00
0.116
1.68
0.37
Umbriel
Uranus
1169
266.00
4.144
0.13
0.004
1.35 x 10–5
1.46
0.21
Ariel
Uranus
1158
190.90
2.520
0.04
0.001
1.56 x 10–5
1.59
0.39
Dione
Saturn
1123
377.42
2.737
0.03
0.002
1.93 x 10–6
1.48
0.6
Tethys
Saturn
1066
294.70
1.888
1.09
0.000
1.09 x 10–6
0.97
0.8

a Orbital inclinations are given relative to the planet’s equator, except for the Moon which is given relative to the ecliptic. The Moon’s orbital inclination relative to the Earth’s equator ranges from 18.28 to 28.58 degrees; it reaches its maximum inclination every 18.6 years.
b Diameter of solid body; diameter at cloud top is 5550 km.
R = retrograde.
Sources: Diameters, densities, and albedos from JPL Solar System Dynamics group; other data from The Astronomical Almanac.

Table last updated 2011 January.