Body diameters to scale. Positions and surface artwork are illustrative; Saturn’s rings are excluded.
A change of perspective
4.0819× 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.
Europa: Diameter is twice JPL’s volume-equivalent mean radius of 1,560.80 km: 3,121.6 km. It describes a sphere with Europa’s volume, rather than an equatorial or polar span. The listed radius sigma of 0.30 km corresponds to a diameter sigma of 0.60 km.
Earth: Twice the source mean radius; body diameter only, excluding rings.
Diameter is twice JPL’s volume-equivalent mean radius of 1,560.80 km: 3,121.6 km. It describes a sphere with Europa’s volume, rather than an equatorial or polar span. The listed radius sigma of 0.30 km corresponds to a diameter sigma of 0.60 km.
Europa’s mean diameter is 3,121.6 km, compared with 3,474.8 km for the Moon. Dividing these diameters gives about 0.898, so a model with a 10 cm Moon would have a Europa about 8.98 cm across. This compares linear size, not mass or orbital distance. Both diameters are calculated by doubling the mean radii in JPL’s satellite parameter table.
JPL defines mean radius using an equal-volume sphere and credits its Europa radius to Archinal and colleagues’ 2018 report. Doubling the radius also doubles its quoted uncertainty; the stored diameter is therefore a measured estimate. Equatorial and polar diameters describe particular directions instead. Any accompanying artwork is illustrative. See our measurement methodology for how to read size comparisons.