The Strange Tailing Side of Saturns Iapetus
Explanation:
What has happened to Saturn's moon Iapetus?
Vast sections of
this strange world
are dark as
coal, while others are as bright
as ice.
The composition of the dark material is unknown, but
infrared
spectra indicate that it possibly contains some dark form of
carbon.
Iapetus also has an unusual
equatorial ridge that makes it appear like a
walnut.
To help better understand this mysterious moon,
NASA
directed the
robotic Cassini spacecraft
orbiting Saturn to swoop
within 2,000 kilometers just last month.
Pictured above,
from about 75,000 kilometers out, Cassini's trajectory allowed unprecedented imaging
of the hemisphere of Iapetus that is
always trailing.
A huge impact crater seen in the south spans a tremendous 450 kilometers
and appears superposed on an
older crater of similar size.
The
dark material
is seen increasingly coating the easternmost part of
Iapetus, darkening craters and highlands alike.
Close inspection indicates that the dark coating typically faces the moon's
equator.
Whether Iapetus' colors are the result of
unusual episodes of internal
volcanism or
external splattering remains unknown.
This and other images from Cassini's
Iapetus flyby are being studied for even greater clues.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.