[meteorite-list] Saturn's Moon Iapetus Is the Yin-and-Yang of the Solar System

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed, 12 Sep 2007 17:22:18 -0700 (PDT)
Message-ID: <200709130022.RAA15261_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.cfm?release=2007-101

Saturn's Moon Iapetus Is the Yin-and-Yang of the Solar System
Jet Propulsion Laboratory
September 12, 2007

PASADENA, Calif. - Scientists on the Cassini mission to Saturn are
poring through hundreds of images returned from the Sept. 10 flyby of
Saturn's two-toned moon Iapetus. Pictures returned late Tuesday and
early Wednesday show the moon's yin and yang--a white hemisphere
resembling snow, and the other as black as tar.

Images show a surface that is heavily cratered, along with the mountain
ridge that runs along the moon's equator. Many of the close-up
observations focused on studying the strange 20-kilometer high (12 mile)
mountain ridge that gives the moon a walnut-shaped appearance.

"The images are really stunning," said Tilmann Denk, Cassini imaging
scientist at the Free University in Berlin, Germany, who was responsible
for the imaging observation planning. "Every new picture contained its
own charm. I was most pleased about the images showing huge mountains
rising over the horizon. I knew about this scenic viewing opportunity
for more than seven years, and now the real images suddenly materialized."

This flyby was nearly 100 times closer to Iapetus than Cassini's 2004
flyby, bringing the spacecraft to about 1,640 kilometers (1,000 miles)
from the surface. The moon's irregular walnut shape, the mountain ridge
that lies almost directly on the equator and Iapetus' brightness
contrast are among the key mysteries scientists are trying to solve.

"There's never a dull moment on this mission," said Bob Mitchell,
Cassini program manager, NASA's Jet Propulsion Laboratory, Pasadena,
Calif. "We are very excited about the stunning images being returned.
There's plenty here to keep many scientists busy for many years."

"Our flight over the surface of Iapetus was like a non-stop free fall,
down the rabbit hole, directly into Wonderland! Very few places in our
solar system are more bizarre than the patchwork of pitch dark and snowy
bright we've seen on this moon," said Carolyn Porco, Cassini imaging
team leader at the Space Science Institute, Boulder, Colo.

The return of images and other data was delayed early Tuesday due to a
galactic cosmic ray hit which put the spacecraft into a precautionary
state called safe mode. This occurred after the spacecraft had placed
all of the flyby data on its data recorders and during the first few
minutes after it began sending the data home. The data flow resumed
later that day and concluded on Wednesday. The spacecraft is operating
normally and its instruments are expected to return to normal operations
in a few days.

"Iapetus provides us a window back in time, to the formation of the
planets over four billion years ago. Since then its icy crust has been
cold and stiff, preserving this ancient surface for our study," said
Torrence Johnson, Cassini imaging team member at JPL.

Cassini's multiple observations of Iapetus will help to characterize the
chemical composition of the surface; look for evidence of a faint
atmosphere or erupting gas plumes; and map the nighttime temperature of
the surface. These and other results will be analyzed in the weeks to come.

Iapetus flyby raw images are available at: http://saturn.jpl.nasa.gov
and http://www.nasa.gov/cassini and http://ciclops.org.

The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. JPL, a division of
the California Institute of Technology in Pasadena, manages the Cassini
mission for NASA's Science Mission Directorate, Washington, D.C. The
Cassini orbiter and its two onboard cameras were designed, developed and
assembled at JPL. The imaging team is based at the Space Science
Institute, Boulder, Colo.

RELATED MULTIMEDIA: Video file with animation, images and sound bites
will air tomorrow on NASA TV.

------------------------------------------------------------------------

Media contact: Carolina Martinez 818-354-9382
Jet Propulsion Laboratory, Pasadena, Calif.
carolina.martinez at jpl.nasa.gov

Preston Dyches 720-974-5859
Space Science Institute, Boulder, Colo.
media at ciclops.org

2007-101
Received on Wed 12 Sep 2007 08:22:18 PM PDT