Body diameters to scale. Positions and surface artwork are illustrative; Saturn’s rings are excluded.
A change of perspective
11.348× the diameter. See how the two worlds measure up.
Diameter is a distance across an object. Volume grows with the cube of that distance.
Choose a size to bring this comparison down to Earth.
Dione: Twice JPL’s volume-equivalent mean radius of 561.40 km: diameter = 1,122.8 km. This is the diameter of a sphere with Dione’s volume, rather than an equatorial or polar diameter. Doubling the tabulated radius sigma of 0.40 km gives a diameter sigma of 0.8 km.
Earth: Twice the source mean radius; body diameter only, excluding rings.
Twice JPL’s volume-equivalent mean radius of 561.40 km: diameter = 1,122.8 km. This is the diameter of a sphere with Dione’s volume, rather than an equatorial or polar diameter. Doubling the tabulated radius sigma of 0.40 km gives a diameter sigma of 0.8 km.
Dione, a moon of Saturn, has a mean diameter of approximately 1,122.8 km. The JPL satellite parameter table supplies its mean radius; doubling that value gives the diameter used here.
Using the same JPL table, Earth’s Moon has a mean diameter of 3,474.8 km. Dividing the diameters makes Dione about 32.3% as wide, or the Moon about 3.09 times as wide. If the Moon were represented by a 10 cm ball, Dione would be about 3.23 cm across. These calculated ratios compare linear size, not mass or orbital distance.
JPL defines mean radius by equivalent volume and attributes these radius values to Archinal and colleagues’ 2018 report. Ratios are rounded; measured dimensions have uncertainty. Equatorial and polar measurements describe specific axes and should not be mixed with this mean diameter. See the measurement guide. Artwork is illustrative, not a calibrated surface map.