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Saturn's moon images 'look just like Namibia'
WASHINGTON - Saturn's moon Titan has huge regions covered with dunes, possibly made out of ice crystals, sand or some other unknown material, international space scientists reported on Thursday.
Images of Titan beamed back to earth from the joint US-European
Cassini mission look very much like sand dunes in the Sahara
desert, Namibia, Saudi Arabia and Australia, the researchers said.
"It's bizarre," said Ralph Lorenz of the University of Arizona,
who worked on the study.
"These images from a moon of Saturn look just like radar images
of Namibia or Arabia.
Titan's atmosphere is thicker than Earth's, its gravity is
lower, its sand is certainly different - everything is different
except for the physical process that forms the dunes and resulting
landscape."
The Cassini craft was launched in 1997 and reached Saturn in
2004 after an interplanetary cruise that took it past Venus and
Jupiter.
The latest radar images show the dunes are up to 150 metres high
and hundreds of kilometres long.
Dark patches on Titan, the largest of Saturn's 47 moons, were at
first thought to be seas - but now they appear to be largely made
up of these dunes.
Titan's flat surface is very cold, with a temperature of minus
180°C and scientists believe its thick atmosphere may
occasionally rain methane.
The existence of pristine dunes, piled over other geological
features, shows that wind recently blew fine grains of some
material around, the researchers wrote in their report, published
in the journal Science.
It could be sand, ice or something else, they added.
But they called the presence of the dunes "comforting", because
at least the processes that lead to their formation can be studied
on Earth.
Also on Thursday, the European Space Agency released new movies
of the descent of its Huygens probe to Titan's surface.
The probe is piggybacked onto the Cassini spacecraft.
The four-hour movie shows what the probe actually "saw" within
the few hours of the descent and the eventual landing.
"At first the Huygens camera just saw haze over the distant
surface," said Erich Karkoschka of the University of Arizona, who
created the movies.
Then the moon's sandy surface comes into view.
* The films can be seen on the Internet at saturn.esa.int
"It's bizarre," said Ralph Lorenz of the University of Arizona, who
worked on the study."These images from a moon of Saturn look just
like radar images of Namibia or Arabia.Titan's atmosphere is
thicker than Earth's, its gravity is lower, its sand is certainly
different - everything is different except for the physical process
that forms the dunes and resulting landscape."The Cassini craft was
launched in 1997 and reached Saturn in 2004 after an interplanetary
cruise that took it past Venus and Jupiter.The latest radar images
show the dunes are up to 150 metres high and hundreds of kilometres
long.Dark patches on Titan, the largest of Saturn's 47 moons, were
at first thought to be seas - but now they appear to be largely
made up of these dunes.Titan's flat surface is very cold, with a
temperature of minus 180°C and scientists believe its thick
atmosphere may occasionally rain methane.The existence of pristine
dunes, piled over other geological features, shows that wind
recently blew fine grains of some material around, the researchers
wrote in their report, published in the journal Science.It could be
sand, ice or something else, they added.But they called the
presence of the dunes "comforting", because at least the processes
that lead to their formation can be studied on Earth.Also on
Thursday, the European Space Agency released new movies of the
descent of its Huygens probe to Titan's surface.The probe is
piggybacked onto the Cassini spacecraft.The four-hour movie shows
what the probe actually "saw" within the few hours of the descent
and the eventual landing."At first the Huygens camera just saw haze
over the distant surface," said Erich Karkoschka of the University
of Arizona, who created the movies.Then the moon's sandy surface
comes into view.* The films can be seen on the Internet at
saturn.esa.int or www.lpl.arizona.edu/DISR/.
