[meteorite-list] Pluto's Big Moon Charon Reveals a Colorful and Violent History
From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Fri, 2 Oct 2015 16:34:06 -0700 (PDT)
Pluto's Big Moon Charon Reveals a Colorful and Violent History
October 1, 2015
NASA's New Horizons spacecraft has returned the best color and the
highest resolution images yet of Pluto's largest moon, Charon - and
these pictures show a surprisingly complex and violent history.
At half the diameter of Pluto, Charon is the largest satellite relative
to its planet in the solar system. Many New Horizons scientists expected
Charon to be a monotonous, crater-battered world; instead, they're
finding a landscape covered with mountains, canyons, landslides,
surface-color variations and more.
"We thought the probability of seeing such interesting features on this
satellite of a world at the far edge of our solar system was low," said
Ross Beyer, an affiliate of the New Horizons Geology, Geophysics and
Imaging (GGI) team from the SETI Institute and NASA Ames Research Center
in Mountain View, California, "but I couldn't be more delighted with
what we see!"
High-resolution images of the Pluto-facing hemisphere of Charon, taken
by New Horizons as the spacecraft sped through the Pluto system on July
14, and transmitted to Earth on Sept. 21, reveal details of a belt of
fractures and canyons just north of the moon's equator. This great
canyon system stretches across the entire face of Charon, more than a
thousand miles, and probably around onto Charon's far side. Four times
as long as the Grand Canyon, and twice as deep in places, these faults
and canyons indicate a titanic geological upheaval in Charon's past.
"It looks like the entire crust of Charon has been split open," said
John Spencer, deputy lead for GGI at the Southwest Research Institute in
Boulder, Colorado. "In respect to its size relative to Charon, this
feature is much like the vast Valles Marineris canyon system on Mars."
The team has also discovered that the plains south of the canyon,
informally referred to as Vulcan Planum, have fewer large craters than
the regions to the north, indicating that they are noticeably younger.
The smoothness of the plains, as well as their grooves and faint ridges,
are clear signs of wide-scale resurfacing.
One possibility for the smooth surface is a kind of cold volcanic
activity, called cryovolcanism. "The team is discussing the possibility
that an internal water ocean could have frozen long ago, and the
resulting volume change could have led to Charon cracking open, allowing
water-based lavas to reach the surface at that time," said Paul Schenk,
a New Horizons team member from the Lunar and Planetary Institute in
Even higher-resolution Charon images and composition data are still to
come as New Horizons transmits data, stored on its digital recorders,
over the next year - and as that happens, "I predict Charon's story will
become even more amazing!" said mission Project Scientist Hal Weaver, of
the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland.
The New Horizons spacecraft is currently 3.1 billion miles (5 billion
kilometers) from Earth, with all systems healthy and operating normally.
New Horizons is part of NASA's New Frontiers Program, managed by the
agency's Marshall Space Flight Center in Huntsville, Alabama. APL
designed, built, and operates the New Horizons spacecraft and manages
the mission for NASA's Science Mission Directorate. SwRI leads the
science mission, payload operations, and encounter science planning.
Click on the image for the full image and caption.
Charon in Enhanced Color: NASA's New Horizons captured this
high-resolution enhanced color view of Charon just before closest
approach on July 14, 2015. The colors are processed to best highlight
the variation of Charon's surface properties.
Charon in Detail: Charon's cratered uplands at the top are broken by
series of canyons, and replaced on the bottom by the rolling plains of
the informally named Vulcan Planum.
Strikingly Different Worlds: A composite of enhanced color images
highlights the striking differences between Pluto and Charon.
Flying over Charon: Images from NASA's New Horizons spacecraft were
used to create this flyover video of Pluto's largest moon, Charon.
Received on Fri 02 Oct 2015 07:34:06 PM PDT