Ariel

Ownership: UCP

Ariel is a relatively small satellite and the brightest moon of Uranus.

Orbital parameters

Mean orbital distance: 191,240 km
Rotational period: 2.520379 days
Orbital period: 2.520379 days
Mean orbital velocity: 5.52 km/sec
Orbital eccentricity: 0.0034
Orbital inclination: 0.31 deg

Physical parameters

Mass: 1.27e+21 kg
Equatorial radius: 578.9 km
Mean density: 1.56 gm/cm^3
Escape velocity: 0.541 km/sec
Visual geometric albedo: 0.34

The surface is pock-marked with craters, but the most outstanding features are long rift valleys stretching across the entire surface. Canyons much like the ones on Mars appear in the pictures. The canyon floors appear as though they have been smoothed by a fluid. The fluid could not have been water because water acts like steel at these temperatures. The flow marks might have been made by ammonia, methane or even carbon monoxide.