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3-D animation of the surface of Titan, based on one of the images from the Hyugens landing:


http://wwwuser.oat.ts.astro.it/messerotti/Titano/Home_Eng/Titan3D_Trieste_Eng.htm

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Saharan Sand Dunes Found on Saturn's Moon Titan
By Sara Goudarzi
Staff Writer
posted: 04 May 2006
02:13 pm ET


Image of the Belet sand sea at about 12 degrees South and 100 degrees West on Titan. Credit: Science.



Aerial view of the Namib desert from the Space Shuttle mission STS-107 at 283 kilometer altitude. Credit: NASA Johnson Space Center.


Recent images of Titan, Saturn's largest moon, bear a striking resemblance to some of the deserts on Earth. The pictures, captured by the Cassini spacecraft as it flew by Titan last October and released today, show sand dunes at Titan's equator much like those in the Sahara desert. "It's bizarre," said Ralph Lorenz of University of Arizona's Lunar and Planetary Laboratory. "These images from a moon of Saturn look just like radar images of Namibia or Arabia."


On Earth, all wind is ultimately a result of heat differences produced by sunlight that warms the planet unevenly. Scientists have long assumed Titan is too far from the Sun to have solar-driven surface winds powerful enough to cause sand dunes. But hey have more recently learned that Saturn's powerful gravity creates tidal effects in Titan's thick atmosphere. This tidal force, almost 400 times greater than that of Earth's moon tugging at our oceans, dominates near surface winds on Titan and sculpts dunes that are up to 330 feet high.


Rows of sand

The new images, revealed in the May 5 issue of the journal Science, are evidence that these dunes were built from winds that blow in one direction before switching to another and then back to the first direction and so on. The tides cause wind to change direction as they drive winds toward the equator, Lorenz said. This back and forth pattern cause the sand dunes to build up in long parallel lines. These tidal winds combined with Titan's west-to-east zonal winds create dunes aligned nearly west-to-east everywhere except close to mountains, which alter wind direction.


Scientists also thought that the dark regions on Titan's equator were in fact seas of liquid ethane that trap sand. But the images reveal something different. "If you look at the dunes, you see tidal winds might be blowing sand around the moon several times and working it into dunes at the equator," Lorenz said. "It's possible that tidal winds are carrying dark sediments from higher latitudes to the equator, forming Titan's dark belt."


Sand formation

The sand on Titan might have formed when liquid methane rained and eroded the ice bedrock. Although it doesn't rain frequently on Titan, when it does rain it really pours. Energetic rain that triggers flash floods may be a mechanism for making sand, Lorenz said. The sand could also have come from organic solids produced by photochemical reactions in Titan's atmosphere. "It's exciting that the radar, which is mainly to study the surface of Titan, is telling us so much about how winds on Titan work," Lorenz said. "This will be important information for when we return to Titan in the future, perhaps with a balloon."

http://www.space.com/scienceastronomy/060504_sands_titan.html

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Landing on Titan � the new movies

4 May 2006



A little more than one year after the spectacular descent of ESA�s Huygens on Saturn�s giant moon Titan, scientists from the probe�s Descent Imager/Spectral Radiometer (DISR) have released two new movies of the descent. These represent the best visual product from the mission obtained so far and the most realistic way yet to experience the landing on a far-away world.


These movies were built thanks to the data collected by DISR on 14 January 2005, during the 147-minutes plunge through Titan's thick orange-brown atmosphere to a soft sandy riverbed. The data were analysed for months after the landing. The movie �View from Huygens on 14 January 2005� shows in 4 minutes 40 seconds 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 DISR team member Erich Karkoschka, from the DISR team at the University of Arizona and creator of the movies.


"The haze started to clear only at about 60 kilometres altitude, making it possible to resolve surface features as large as 100 metres," he continued. "But only after landing could the probe's camera resolve little grains of sand millions and millions times smaller than Titan. A movie is a perfect medium to show such a huge change of scale."


To see the first of the two movies, click on the following link (Macromedia Flash player required):

http://www.esrin.esa.it/export/esaSC/SEMKVQOFGLE_index_1.html

To download a hi-resolution version of the movie, click here (148MB):

(You have to see this movie - it is amazing!!!!)

http://esamultimedia.esa.int/multimedia/video/Movie_HiRes+Narration_25Apr06.wmv

The hi-resolution version of the movie is 4 minutes 40 seconds long. At about 2 minutes 33 seconds into the movie, you can see the three "drainage basins" and "shoreline" come into view at the bottom of the picture - the ones Mithridates and I discussed last year.


Another amazing picture available is the following:




This composite view of Titan�s surface is built with images taken on 14 January 2005 by the Descent Imager/Spectral Radiometer (DISR) on board ESA�s Huygens mission, after touch-down. The composite is compared with a similarly scaled picture taken on the Moon�s surface. Objects near the centre of the picture are roughly the size of a man�s foot, while objects at the horizon are a fraction of a man�s height.

For hi-res JPG (90 kb):

http://esamultimedia.esa.int/images/cassini_huygens/posterf_H.jpg


Credits: ESA/NASA/JPL/University of Arizona

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This side-by-side image shows a Cassini radar image (on the left) of what is the largest body of liquid ever found on Titan's north pole, compared to Lake Superior (on the right). This close-up is part of a larger image and offers strong evidence for seas on Titan. These seas are most likely liquid methane and ethane. Credit: NASA/JPL/GSFC

New Images: Huge Seas on Saturn's Moon Titan

By Robin Lloyd
Senior Editor
posted: 13 March 2007
03:13 pm ET


Updated 3:55 p.m. ET

A NASA spacecraft has found evidence of huge seas, likely filled with liquid methane or ethane, in the high northern latitudes of Saturn's moon Titan. One of the seas [above] is larger than any of the Great Lakes in North America and possibly only slightly smaller than the Caspian Sea, which lies between Russia and Iran and is the largest lake on Earth. (Lakes are typically landlocked but the Caspian Sea was called a sea when it was initially discovered because it tasted salty.)


The very dark features, detected by a radar instrument on NASA's Cassini spacecraft, are located near Titan's north pole, and one of them measures at least 39,000 square miles (100,000 square kilometers), much larger than similar features seen before on the Saturnian moon.


Big moon, big seas

Titan is the second largest moon in the solar system and is about 50 percent larger than Earth's moon. Methane is the principal component of natural gas. Ethane, also a colorless and odorless gas at room temperature, is the second largest component of natural gas.


"We've long hypothesized about oceans on Titan and now with multiple instruments we have a first indication of seas that dwarf the lakes seen previously," said Jonathan Lunine, a University of Arizona scientist who works on Cassini data.


One goal of the mission was to find seas or lakes on Titan. So far, it's been lakes and now the small seas. Before the spacecraft arrived at Saturn in July 2004, one scientist predicted that Cassini would find full-on oceans with waves on Titan, but that finding has yet to turn up.


Testing the liquid idea

There is no proof yet that these seas contain liquid, but their shape and darkness indicate smoothness, and other properties point to the presence of liquid, Lunine said. The liquid is probably methane or ethane because those compounds are abundant in clouds in Titan's atmosphere.


Imaging cameras on Cassini also captured an overall shot of the region around the huge sea , so scientists currently are trying to use them to further test the idea that the seas are filled with liquid:




Radar data of the largest sea basin shows details similar to those seen in earlier radar observations of much smaller, liquid-filled lakes, Lunine said. Titan's high northern latitudes are dotted with seas hundreds of miles across, and hundreds of smaller lakes that vary from several to tens of miles across.


Scientists have long thought that Titan's surface supplies methane to the moon's atmosphere, so the presence of lakes and seas makes sense in light of that.


The seas discovery has prompted Cassini mission engineers to repoint Cassini's radar instrument to pass directly over the dark areas during a May flyby of the moon.

http://www.space.com/scienceastronomy/070313_titan_lakes.html