APOD: 2026 July 5 Б Saturns Iapetus: Painted Moon
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 snow.
To help better understand this unusually tinted moon,
in 2007
NASA
directed the
robotic Cassini spacecraft then orbiting
Saturn to swoop within 2,000 kilometers.
Pictured here, from about 75,000 kilometers out,
is the hemisphere of Iapetus that is
always trailing.
A large impact crater seen in the south spans 500 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.
A leading hypothesis is that the dark material is mostly a form of carbon-rich
soil leftover from when relatively warm but dirty ice
sublimates.
An initial coating of this dark material may have been
effectively painted on by the accretion of meteor-liberated debris from
other moons.
Jigsaw Moon:
Astronomy Puzzle of the Day
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.
