Even
the dark areas, thought to be water frost and ice, are fairly bright with
about 50 percent reflectance. The bright streaks may be related to impacts
by objects that throw out pulverized ice grains from beneath the ice-covered
surface. Some of the bright streaks are not straight but have a curved appearance
similar to the grooved, icy terrain on Jupiter's satellite Ganymede seen
in Voyager photographs taken at this resolution. |
 |
Scientists
do knot yet know if a satellite of Rhea's size (approximately 1,500 kilometers
or 900 miles in diameter) can have an active thermal history like Ganymede's,
but higher resolution photographs taken by Voyager should reveal clues to
its history. |
|