Saturns Iapetus: Painted Moon in 3D
Explanation:
What has happened to Saturn's moon Iapetus?
Vast sections of
this strange world are dark brown,
while others are as bright white.
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 seemingly painted moon,
NASA directed the
robotic Cassini spacecraft orbiting Saturn to swoop
within 2,000 kilometers in 2007.
Iapetus is
pictured here in 3D.
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 and is less than a meter thick.
A leading hypothesis is that the dark material is mostly
dirt leftover when relatively warm but dirty ice
sublimates.
An initial coating of
dark material may have been effectively painted
on by the accretion of meteor-liberated debris from
other moons.
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.
