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NEWS - News Releases - 2005
Cassini Images of Titan Reveal an Active, Earth-like World
March 9, 2005
(Source: Jet Propulsion Laboratory)
Saturn's largest and hazy moon, Titan, has a surface shaped largely by Earth-like
processes of tectonics, erosion, winds, and perhaps volcanism. The findings are
published in this week's issue of the journal Nature.
Titan, long held to be a frozen analog of early Earth, has liquid methane on its cold
surface, unlike the water found on our home planet. Among the new discoveries is what
may be a long river, roughly 1,500 kilometers long (930 miles). Scientists have also
concluded that winds on Titan blow a lot faster than the moon rotates, a fact long
predicted but never confirmed until now.
Tectonism (brittle fracturing and faulting) has clearly
played a role in shaping Titan's surface. "The only
known planetary process that creates large-scale linear
boundaries is tectonism, in which internal processes
cause portions of the crust to fracture and sometimes
move either up, down or sideways," said Dr. Alfred
McEwen, Cassini imaging team member from the
University of Arizona, Tucson. "Erosion by fluids may
accentuate the tectonic fabric by depositing dark
materials in low areas and enlarging fractures. This
interplay between internal forces and fluid erosion is
very Earth-like."
Cassini images collected during close flybys of the
Scrutinizing Titan's Surface
moon show dark, curving and linear patterns in various
regions on Titan, but mostly concentrated near the
south pole. Some extend up to 1,500 kilometers (930 miles) long. Images from the
European Space Agency's Huygens probe show clear evidence for small channels a few
kilometers long, probably cut by liquid methane. Cassini imaging scientists suggest that
the dark, curved and linear patterns seen in the Cassini orbiter images of Titan may also
be channels, though there is no direct evidence for the presence of fluids. If these
features are channels, it would make the ones near the south pole nearly as long as the
Snake River, which originates in Wyoming and flows across four states.
Since most of the cloud activity observed on Titan by Cassini has occurred over the
south pole, scientists believe this may be where the cycle of methane rain, channel
carving, runoff, and evaporation is most active, a hypothesis that could explain the
presence of the extensive channel-like features seen in this region. In analyzing clouds
of Titan's lower atmosphere, scientists have concluded that the winds on Titan blow
faster than the moon rotates, a phenomenon called super-rotation. In contrast, the jet
streams of Earth blow slower than the rotation rate of our planet.
"Models of Titan's atmosphere have indicated that it
should super-rotate just like the atmosphere of Venus,
but until now there have been no direct wind
measurements to test the prediction," said Cassini
imaging team member Dr. Tony DelGenio of NASA's
Goddard Institute for Space Studies, in New York.
DelGenio made the first computer simulation
predicting Titan super-rotation a decade ago.
Tracing Surface Features on
Titan -- Mosaic
Titan's winds are measured by watching its clouds
move. Clouds are rare on Titan, and those that can be
tracked are often too small and faint to be seen from
Earth. Ten clouds have been tracked by Cassini, giving
wind speeds as high as 34 meters per second (about 75
miles per hour) to the east -- hurricane strength -- in
Titan's lower atmosphere. "This result is consistent
with the predictions of Titan weather models, and it
suggests that we now understand the basic features of
how meteorology works on slowly rotating planets,"
said Del Genio.
"We've only just begun exploring the surface of Titan,
but what's struck me the most so far is the variety of the surface patterns that we¿re
seeing. The surface is very complex, and shows evidence for so many different
modification processes," said Dr. Elizabeth Turtle, Cassini imaging team associate in
the Lunar and Planetary Laboratory at the University of Arizona, Tucson and co-author
of one of the papers in Nature.
"Throughout the solar system, we find examples of solid bodies that show tremendous
geologic variation across their surfaces. One hemisphere often can bear little
resemblance to the other," said Dr. Carolyn Porco, Cassini imaging team leader, Space
Science Institute, Boulder, Colo. "On Titan, it's very likely to be this and more."
These results are based on Cassini orbiter images of Titan collected over the last eight
months during a distant flyby of the south pole and three close encounters of Titan's
equatorial region. Cassini cameras have covered 30 percent of Titan's surface, imaging
features as small as 1 to 10 kilometers (0.6 to 6 miles). Cassini is scheduled to make 41
additional close Titan flybys in the next three years.
For images and information on the Cassini mission visit 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. The Jet Propulsion Laboratory, a division of the
California Institute of Technology in Pasadena, manages the Cassini-Huygens mission
for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was
designed, developed and assembled at JPL.
Contacts:
Carolina Martinez (818) 354-9382
Jet Propulsion Laboratory, Pasadena, Calif.
Preston Dyches (720) 974-5823
Cassini Imaging Central Laboratory for Operations
Space Science Institute, Boulder, Colo.
NEWS RELEASE: 2005-041
It's raining methane on icy Titan Weather processes similar to Earth's:[1R Edition]
Warren E. Leary. International Herald Tribune Paris:Jan 24, 2005. p. 6
Many of the weather processes found on Earth, like rain falling on hills and flowing down channels into river beds and
around islands, also are happening on Saturn's icy moon Titan, but with different materials, scientists say.
A week after a European space probe penetrated Titan's perpetual haze and landed on its surface, scientists
say data show that the frozen moon has a dynamic, eroding surface transformed by liquid methane playing
the role that water serves on Earth.
Methane natural gas held in liquid form by the intense pressure and minus-180-Celsius, or minus-290-degree
Fahrenheit, temperatures of Titan's surface rains from the sky and courses down highlands through channels
into lakebeds and broad deltas, similar to processes that take place on Earth, they said.
"We now have the key to understanding what shapes Titan's landscape," Martin Tomasko of the University of
Arizona at Tucson told a news conference in Paris to describe the mission's first scientific results. "The
physical processes shaping Titan are much the same as those shaping Earth."
Elated scientists said analyzing data from the Huygens probe that parachuted through Titan's atmosphere
and landed on its surface on Jan. 14 will keep them busy for years. But an early look at this information,
including some 350 pictures, confirms that the moon could be a model for processes that happened on Earth
billions of years ago.
"We are really extremely excited about these results," Jean- Pierre Lebreton, mission manager for the
European Space Agency's Huygens project said Friday. The first close-up look is so tantalizing that scientists
should start dreaming about one day sending a rover spacecraft to Titan to explore its unique terrain, he
said.
The Huygens probe, carried to Saturn by the National Aeronautics and Space Administration's Cassini
spacecraft, operated for several hours in Titan's atmosphere and on the surface. The spacecraft landed on a
surface with the consistency of loose sand that scientists said appeared to be moistened by methane rain.
Heat generated by the spacecraft warmed the surface material, causing bursts of methane gas to boil up
around the craft, scientists said.
Tomasko said the craft landed in a spot that was dry at the time, but appeared to have been rained on
recently. "Does that mean yesterday or the day before, the week before? We don't really know," he said.
Since no liquid methane was spotted on the surface, he said, it is possible that Huygens landed in an area
that is relatively arid.
"It's more like Arizona or someplace like that, where the river beds are dry most of the time. But after rain,
you might have open flowing liquids and pools. These pools gradually dry out; the liquid sinks down into the
surface."
Tobias Owen of the University of Hawaii's Institute for Astronomy, who studied Huygens's atmospheric
readings, noted that nitrogen is the dominant gas in Titan's upper regions, but the concentrations of methane
increase sharply near the surface.
This indicates that there is a big source of methane at ground level, he said, mostly likely liquid methane very
near the surface or on top that is continually renewing the supply of the gas into the atmosphere.
Scientists said the surface of Titan is covered with dark deposits from the organic materials that make up the
haze that shrouds it. The material settles out of the atmosphere and, when washed from higher elevations by
methane rain, concentrates at the bottom of drainage channels and riverbeds.
Instrument scans indicate that some of the surface, which is lighter in color than surrounding areas, is hardwater ice that flowing methane carves into channels. Surface images taken by Huygens show small rounded
pebbles in a dry riverbed nearby, scientists said, adding that spectral analysis of the pebbles indicated that
they were made of dirty water ice that had somehow been worn smooth by erosion.
Credit: The New York Times
Space Probe Makes Science Fiction Wonders of Childhood Real
Lawrence M. Krauss. New York Times (Late Edition (east Coast)). New York, N.Y.:Jan 25, 2005. p. F.3
Dr. Lawrence M. Krauss is the director of the Center for Education and Research in Cosmology and Astrophysics at Case Western
Reserve University. His most recent book was ''Atom.''
A small probe stranded on a far-away and hostile world operates for two precious hours at a temperature of
300 degrees below zero Fahrenheit, desperately transmitting information to its mother ship before that
spacecraft disappears below the horizon, leaving the small explorer alone on the spongy ground of its new
alien home, slowly losing power and slated to eternally rest on a frozen moon 750 million miles from Earth.
I could be accused of anthropomorphizing, but the plight of the small Cassini-Huygens probe resting by a
hydrocarbon-coated ice and methane plain on Saturn's largest moon, Titan, captured my imagination far
more than anything the astronauts in the International Space Station might be doing now.
What really did it for me was the orange sky. It showed with striking clarity that the science fiction wonders
that I dreamed of as a child are being revealed by our unmanned space probes in a way that is both more
enthralling and informative than anything likely to come from spending all of NASA's funds on a few more
astronauts on the Moon, or, eventually, Mars.
I admit to having already been hooked on Internet images like those from Martian Rovers on a planet that
that looks suspiciously like a smoggy sunset seen from Los Angeles. But until now, the worlds that were
stunningly brought to my desktop were closer to what I might see exploring an earthly desert than to those
exotic places that had so captured my imagination as a child reading science fiction stories, or looking at
artists' renderings of imaginary planetary surfaces.
But there, as I clicked on the Cassini-Huygens probe Web site, the dark pebbles of dirty hydrocarbon-coated
ice on the surface of Titan jumped out through an orange glow of an atmosphere unlike anything I had ever
seen.
I was instead reminded of old science fiction stories. On the Web I found a recent example of the kind of
thing I used to savor. This was an award-winning short story, ''Slow Life'' by Michael Swanwick, about human
explorers seeking life on Titan.
''People talked a lot about the 'murky orange atmosphere' of Titan, but your eyes adjusted. Turn up the gain
on your helmet, and the white mountains of ice were dazzling! The methane streams carved cryptic runes
into the heights. Then, at the tholin-line, white turned to a rich palette of oranges, reds and yellows.''
So the water-ice is dirtier and the surface darker. But the landscape of Titan is eerily similar to the one Mr.
Swanwick imagined so vividly. Except that the truth is even stranger and more entrancing than his fiction.
I learned from a news conference carried out on Friday by the Cassini-Hugyens probe science team that
there is evidence of active volcanoes on Titan's surface based on argon 40 in the atmosphere. But these do
not spew molten lava. Instead, like the ones I concocted with my childhood chemistry set, these release
flumes of water and ammonia.
There are indeed clouds and methane and hydrocarbon rainstorms, but the reality of a turbulent atmosphere
of methane winds was brought home to me in a way that no writing could. With brilliant foresight, the
Huygens science includes a microphone on the probe. As it fell through the clouds, beginning about 100
miles above the surface, I could listen as well as see the approaching surface as the craft sent out a stream
of photos during its descent. Sitting at my computer in the middle of the night, listening to gusts of alien winds
on a remote moon of Saturn was both eerie and moving.
I consider myself fortunate to be living at a time when humans are as close as they may ever come to seeing
such a truly alien world with methane slush and new colors in the sky. That is probably what drew me to
science in the first place. While literature has the power to lift us from the tedium of everyday existence,
science at its best has the power to transport us to totally different worlds, both literal and metaphorical, to
take us where our imaginations may never have otherwise traveled.
In two short hours, one small unmanned probe changed my direct experience of our solar system in ways
that I never imagined. Now I am craving for more such highs. Perhaps I will witness further probes that may
dive into distant alien seas underneath frozen moons. Perhaps one will send home clear evidence of alien
life existing or extinct.
Realistically, however, the future is likely to be one of cutbacks and shortfalls, with billions of dollars headed
to protect populations that we put in jeopardy, or build costly missile defenses against nonexistent threats.
One can only hope that there is enough imagination left in government to allow us to keep supporting the
missions that do the science that can really change the way we think about our place in the universe.
To boldly go where no one has gone before in ways that only unmanned spacecraft can do will cost so little
in comparison that such an effort shouldn't interfere with the current priority of allowing astronauts to have
new adventures on the Moon.
It is significant in this regard that the Huygens probe was a product of the European Space Agency, working
in concert with NASA and the Jet Propulsion Laboratory. This not only demonstrates that Europe is now a
leading player in space exploration, but it shows that for grand human projects, like the exploration of our
universe or the exploration of space and time on fundamental scales, we can and need to work together on a
global scale.
This is one of the side benefits of the scientific enterprise. But even more than this, the universe continues to
surprise us in ways we can never anticipate. Ultimately it is far more interesting than anything that science
fiction writers or artists may imagine. Life may imitate art, but ultimately it transcends it. Which is why we
sometimes need to turn to the universe itself for inspiration.
Seeing, touching and smelling the extraordinarily Earth-like world of
Titan
Mosaic of river channel and ridge area on Titan
21 January 2005
ESA PR 05-2005. On 14 January ESA's Huygens probe made an historic first ever descent to the surface
of Titan, 1200 million kilometres from Earth and the largest of Saturn's moons.
Huygens travelled to Titan as part of the joint NASA/ESA/ASI Cassini-Huygens mission. Starting at about
150 kilometres altitude, six multi-function instruments on board Huygens recorded data during the
descent and on the surface. The first scientific assessments of Huygens' data were presented during a
press conference at ESA head office in Paris on 21 January.
"We now have the key to understanding what shapes Titan's landscape," said Dr Martin Tomasko,
Principal Investigator for the Descent Imager-Spectral Radiometer (DISR), adding: "Geological evidence
for precipitation, erosion, mechanical abrasion and other fluvial activity says that the physical processes
shaping Titan are much the same as those shaping Earth."
"Islands in the stream"... possible 'islands' on a dark plain
Spectacular images captured by the DISR reveal that Titan has extraordinarily Earth-like meteorology
and geology. Images have shown a complex network of narrow drainage channels running from brighter
highlands to lower, flatter, dark regions. These channels merge into river systems running into lakebeds
featuring offshore 'islands' and 'shoals' remarkably similar to those on Earth.
Data provided in part by the Gas Chromatograph and Mass Spectrometer (GCMS) and Surface Science
Package (SSP) support Dr Tomasko's conclusions. Huygens' data provide strong evidence for liquids
flowing on Titan. However, the fluid involved is methane, a simple organic compound that can exist as a
liquid or gas at Titan's sub-170°C temperatures, rather than water as on Earth.
Titan's rivers and lakes appear dry at the moment, but rain may have occurred not long ago.
Deceleration and penetration data provided by the SSP indicate that the material beneath the surface's
crust has the consistency of loose sand, possibly the result of methane rain falling on the surface over
eons, or the wicking of liquids from below towards the surface.
Two new Titan features - water ice and methane springs
Heat generated by Huygens warmed the soil beneath the probe and both the GCMS and SSP detected
bursts of methane gas boiled out of surface material, reinforcing methane's principal role in Titan's
geology and atmospheric meteorology -- forming clouds and precipitation that erodes and abrades the
surface.
In addition, DISR surface images show small rounded pebbles in a dry riverbed. Spectra measurements
(colour) are consistent with a composition of dirty water ice rather than silicate rocks. However, these
are rock-like solid at Titan's temperatures.
Titan's soil appears to consist at least in part of precipitated deposits of the organic haze that shrouds
the planet. This dark material settles out of the atmosphere. When washed off high elevations by
methane rain, it concentrates at the bottom of the drainage channels and riverbeds contributing to the
dark areas seen in DISR images.
New, stunning evidence based on finding atmospheric argon 40 indicates that Titan has experienced
volcanic activity generating not lava, as on Earth, but water ice and ammonia.
Titan landing site seen from Cassini
Thus, while many of Earth's familiar geophysical processes occur on Titan, the chemistry involved is
quite different. Instead of liquid water, Titan has liquid methane. Instead of silicate rocks, Titan has
frozen water ice. Instead of dirt, Titan has hydrocarbon particles settling out of the atmosphere, and
instead of lava, Titanian volcanoes spew very cold ice.
Titan is an extraordinary world having Earth-like geophysical processes operating on exotic materials in
very alien conditions.
Panel of scientists presenting Huygens results
"We are really extremely excited about these results. The scientists have worked tirelessly for the whole
week because the data they have received from Huygens are so thrilling. This is only the beginning,
these data will live for many years to come and they will keep the scientists very very busy", said JeanPierre Lebreton, ESA's Huygens Project Scientist and Mission manager.
The Cassini-Huygens mission is a cooperation between NASA, ESA and ASI, the Italian space agency.
The Jet Propulsion Laboratory (JPL), a division of the California Institute of Technology in Pasadena, is
managing the mission for NASA's Office of Space Science, Washington DC. JPL designed, developed and
assembled the Cassini orbiter while ESA operated the Huygens atmospheric probe.
For further information, please contact :
ESA Media Relations Division
Tel: +33(0)1.53.69.7155
Fax: +33(0)1.53.69.7690
Exploring Saturn and Titan
• - (http://www.esa.int/SPECIALS/Cassini-Huygens/index.html)
Huygens raw images
• - (http://esamultimedia.esa.int/docs/titanraw/index.htm)
Sounds of Titan
• - (http://www.esa.int/SPECIALS/Cassini-Huygens/SEM85Q71Y3E_0.html)
Related articles
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Islands, rivers and methane springs - latest images of Titan (http://www.esa.int/SPECIALS/CassiniHuygens/SEM48881Y3E_0.html)
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Huygens lands in Titanian mud (http://www.esa.int/SPECIALS/Cassini-Huygens/SEM5YW71Y3E_0.html)
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First images from Titan (http://www.esa.int/SPECIALS/Cassini-Huygens/SEMBQO71Y3E_0.html)
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Europe reaches new frontier – Huygens lands on Titan (http://www.esa.int/SPECIALS/CassiniHuygens/SEMQ1QQ3K3E_0.html)
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Radio astronomers confirm Huygens entry in the atmosphere of Titan
(http://www.esa.int/esaCP/SEM8ZK71Y3E_index_0.html)
Related links
•
NASA's Cassini-Huygens site (http://saturn.jpl.nasa.gov)
•
Italian Space Agency (ASI) (http://www.asi.it)