C) mainly on the far side.
D) only in the dark areas of the lunar poles, where water is not boiled away.
E) only as layered rocks, since the original water was lost long ago.
A circular orbit would have an eccentricity of
A) 0.
B) between 0 and 0.5.
C) between 0.5 and 1.
D) exactly 1.0.
E) infinity.
Which are the four Galilean moons of Jupiter?
A) Europa, Titan, Ganymede, and Callisto
B) Io, Ganymede, Callisto, and Titan
C) Europa, Ganymede, Io, and Triton
D) Io, Europa, Ganymede, and Callisto