Explanation:
Was Saturn's moon Phoebe once a comet?
Images from the robotic
Cassini spacecraft taken two years ago when entering
the neighborhood of
Saturn indicate that
Phoebe
may have originated in the outer
Solar System.
Phoebe's
irregular surface,
retrograde orbit, unusually dark surface,
assortment of large and small craters, and low average density
appear consistent with the
hypothesis that Phoebe was once part of the
Kuiper belt of icy comets beyond Neptune before being
captured by Saturn.
Visible in the
above image of Phoebe are craters, streaks, and
layered deposits of light and dark material.
The image was taken from around 30,000 kilometers out from this
200-kilometer diameter moon.
Two weeks after taking the
above image,
Cassini fired its engines
to decelerate into orbit around Saturn.
