In spite of
the meteoric blemishes covering the face of Saturn's moon Iapetus, the
walnut-shaped celestial body was the subject of another photo shoot by the
Cassini spacecraft.
Mission scientists are now poring over
hundreds of snapshots made during the spacecraft's closest-ever flyby with
Iapetus this week,
which show its "yin-and-yang" contrastive halves and strange mountain
range in great detail
"The
images are really stunning," said Tilmann Denk, a Cassini imaging
scientist at the Free University in Berlin who began planning the photo shoot
seven years ago.
The photos traveled
947 million miles (1.52 billion kilometers) to reach Earth from Saturn's
vicinity and were taken only 1,000 miles (1,640 kilometers) from the
surface--100 times closer than Cassini's 2004 flyby.
Close-ups
of Iapetus' hemispheres are revealed by the images: a white half resembling
snow and a second half as black as tar. The snapshots also show the ridge of
mountains 12 miles (20 kilometers) high along Iapetus' equator, which
scientists have recently tried to
explain.
"Iapetus
provides us a window back in time, to the formation of the planets over four
billion years ago," said Torrence Johnson, a Cassini imaging team member at
NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Since then its icy
crust has been cold and stiff, preserving this ancient surface for our
study."
A blast of
galactic cosmic rays delayed delivery of Cassini's latest work by several days,
but the spacecraft automatically entered into a protective "safe
mode" after the event, according to a statement released by NASA. Had the
energetic blast arrived a few days sooner, however, the close-up imaging
opportunity may have been lost due to the temporary shut-down.
NASA said
that Cassini is operating normally, and its scientific instruments "are
expected to return to normal operations in a few days."
"There's
never a dull moment on this mission," said Bob Mitchell, Cassini program
manager at JPL. "We are very excited about the stunning images being
returned. There's plenty here to keep many scientists busy for many
years."
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