Opaque layers of clouds prevented Voyager from seeing Titan's surface during its 1980 flyby. The clouds over the southern hemisphere are lighter in color than over the northern hemisphere. There is a dark hood over the north pole.

Descent Panorama of Saturn's Titan

2006 May 8 

Explanation: You're the first spacecraft ever to descend to Titan -- what do you see? Immediately after the Huygen's probe pierced the cloud deck of Saturn's moon Titan last January, it took a unique series of pictures of one of the Solar System's most mysterious moon's. Those pictures have recently been digitally stitched together to create spectacular panoramas and a dramatic descent movie. Pictured above is a panoramic fisheye view Huygen's obtained from about five kilometers above Titan's surface. The digital projection makes the local surface, mostly flat, appear as a ball, but allows one to see in all directions. Huygen's eventual landing site was in the large dark area below, just right of the center. This relatively featureless, dark, sandy basin appears to be surrounded by light colored hills to the right and a landscape fractured by streambeds and canyons above. Recent evidence indicates that Titan's lakebeds and streambeds are usually dry but sometimes filled with a flashflood of liquid methane from rare torrents of methane rain. 

SOURCE: NASA APOD

Discovered in 1655 by the Dutch astronomer Christiaan Huygens, Titan is the biggest of the 52 known moons orbiting  Saturn. It is a cold world enclosed by a thick, hazy atmosphere impenetrable by telescopes and cameras.

With an equatorial radius of 2,575 kilometers (1,600 miles), Titan is the second largest moon in our solar system. It's bigger than our own moon and even the planet Mercury. Only Jupiter's moon Ganymede is larger than Titan, with a diameter barely 112 kilometers (62 miles) greater.

The temperature at Titan's surface is about minus 178 degrees C (minus 289 degrees F).

Titan orbits Saturn at a distance of about 1.2 million kilometers (745,000 miles), taking almost 16 days to complete a full orbit - 15.94 days to be exact.

Titan is of great interest to scientists because it is the only moon in the solar system known to have clouds and a mysterious, thick, planet-like atmosphere. In 1980, NASA's Voyager 1 spacecraft tried to take close up images of the natural features of Titan's landscape but was unable to penetrate the thick clouds. Instead, the images showed only slight color and brightness variations in the atmosphere. Titan's atmospheric pressure is about 60 percent greater than Earth's - roughly the same pressure found at the bottom of a swimming pool.

In 1994, NASA's Hubble Space Telescope recorded pictures of Titan, which suggested that a huge bright "continent" exists on the hemisphere that faces forward in orbit. These Hubble results don't prove that liquid "seas" exist, however; only that Titan has large bright and dark regions on its surface.

NASA's Cassini-Huygens spacecraft (currently orbiting Saturn) should shed new light on Titan's mysteries. The spacecraft's instruments are designed to reveal many of Titan's characteristics. During dozens of flybys, the Cassini orbiter will map Titan with cloud-penetrating radar and collect atmospheric data. The Huygens probe dove through Titan's dense atmosphere on Jan. 14, 2005 with instruments capable of analyzing its components.

Combined with the "big picture" information that the Cassini orbiter will collect during Titan flybys, data from the Huygens probe will provide scientists with critical information that may shed light on ancient questions such as "Where did we come from?" And, "How did the planets form?"

Because of the extremely cold temperatures typical of celestial bodies that are that far away from the Sun, the structure of Titan's chemical atmosphere is in a state of deep freeze. It is this chemical composition that interests scientists a great deal because Titan's atmosphere might consist of compounds similar to those present in the primordial days of the Earth's atmosphere. Titan's thick cloudy atmosphere is mostly nitrogen, like Earth's, but may contain much higher percentages of "smog-like" chemicals such as methane and ethane. The smog may be so thick that it actually rains "gasoline-like" liquids. The organic nature of some of the chemicals found in Titan's atmosphere might indicate that this fascinating moon could harbor some form of life.

Titan in Mythology

A generic name for the children of Ouranos and Gaia. In the Orphic version, the Titans are the ancestors of the human race. The Titans devoured the limbs of Dionysus, the son of Zeus, who intended the child to have dominion over the world. Enraged, Zeus struck the Titans with lightning. The fire burned them to ashes, and from the ashes man was formed.

SOURCE: NASA/JPL

2004 December 20 

Explanation: What does the surface of Titan look like? Thick clouds have always made Saturn's largest moon so mysterious that seemingly farfetched hypotheses like methane rain and lakes have been seriously considered. Later this week, the Cassini spacecraft orbiting Saturn is scheduled to release its probe named Huygens that will actually attempt to land on the shrouded moon in early January. Sketched above is one educated guess of what Huygens might find. In the above depiction, orange hydrocarbons color a landscape covered with lakes and peaks of frozen methane and ammonia. For illustration purposes, the Huygens probe is drawn parachuting down with an oversized Cassini spacecraft orbiting above. Saturn, likely occluded by the clouds, is depicted looming in the distance. What will Huygens really find? Are the building blocks of life frozen onto the surface of Titan? Will the truth be stranger than we imagined? 

SOURCE: NASA APOD

This image shows Titan in ultraviolet and infrared wavelengths. It was taken by Cassini's imaging science subsystem on Oct. 26, 2004, and is constructed from four images acquired through different color filters. Red and green colors represent infrared wavelengths and show areas where atmospheric methane absorbs light. These colors reveal a brighter (redder) northern hemisphere. Blue represents ultraviolet wavelengths and shows the high atmosphere and detached hazes.

Titan has a gigantic atmosphere, extending hundreds of kilometers above the surface. The sharp variations in brightness on Titan's surface (and clouds near the south pole) are apparent at infrared wavelengths. The image scale of this picture is 6.4 kilometers (4 miles) per pixel.

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 Office of Space Science, 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.

For more information, about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org. 

SOURCE: NASA PIA06139

This artist concept shows a mirror-smooth lake on the surface of the smoggy moon Titan.

Cassini scientists have concluded that at least one of the large lakes observed on Saturn’s moon Titan contains liquid hydrocarbons, and have positively identified ethane. This result makes Titan the only place in our solar system beyond Earth known to have liquid on its surface.

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 mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL.

SOURCE: NASA PIA11001

On May 12, 2007, Cassini completed its 31st flyby of Saturn's moon Titan, which the team calls T30. The radar instrument obtained this image showing the coastline and numerous island groups of a portion of a large sea, consistent with the larger sea seen by the Cassini imaging instrument (See http://www.nasa.gov/mission_pages/cassini/multimedia/pia08930.html).

Like other bodies of liquid seen on Titan, this feature reveals channels, islands, bays, and other features typical of terrestrial coastlines, and the liquid, most likely a combination of methane and ethane, appears very dark to the radar instrument. What is striking about this portion of the sea compared to other liquid bodies on Titan is the relative absence of brighter regions within it, suggesting that the depth of the liquid here exceeds tens of meters (tens of yards). Of particular note is the presence of isolated islands, which follow the same direction as the peninsula to their lower right, suggesting that they may be part of a mountain ridgeline that has been flooded. This is analogous to, for example, Catalina Island off the coast of Southern California.

The image as shown is about 160 kilometers (100 miles) by 270 kilometers (170 miles) at 300-meter (980-foot) resolution. The image is centered near 70 degrees north latitude and 310 west longitude.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov .

Credit: NASA/JPL PIA09211

Related Links:

• Cassini - Unlocking Saturn's Secrets
• Exploring the Wetlands of Titan
• Radar Shows Evidence of Seas
• Land of Lakes?
• Titan Sea and Lake Superior
• Ganesa Macula
• Titan's Giant North Pole Cloud
• Titan Occultation
• Two Sides of Dunes
• Liquid Lakes on Titan
• Map of Titan - December 2006 – with labels
• Improving the View of Titan
• Large Tectonic Complex
• Lakes and More Lakes
• Titan's Great Lakes?
• Crater Studies on Titan
• Swimming in Dunes
• Lakes on Titan
• Xanadu's Meandering Rivers
• Titan (T25) Viewed by Cassini's Radar - Feb. 22, 2007
• Titan (T17) Viewed by Cassini's Radar - Sept. 7, 2006
• Titan (T18) Viewed by Cassini's Radar – Sept. 23, 2006
• Titan (T16) Viewed by Cassini’s Radar – July 22, 2006
• Titan (T13) Viewed by Cassini’s Radar - April 30, 2006

This radar image of Titan shows Ganesa Macula, interpreted as a cryovolcano (ice volcano), and its surroundings. Cryovolcanism is thought to have been an important process on Titan and may still be happening today.

This mosaic was made from images obtained by the Cassini radar mapper on two flybys. The lower part of the image was from the flyby on Oct. 26, 2004, while the upper part was from the Jan. 13, 2007, flyby. Ganesa macula is the dark circular feature seen on the lower left of the mosaic. Bright rounded features, interpreted as cryovolcanic flows, are seen towards the top and the right of the mosaic.

This image mosaic was taken in synthetic aperture mode. The resolution of the images is approximately 350 meters (1,150 feet). North is toward the top. The image mosaic is about 570 kilometers (354 miles) wide and 390 kilometers (240 miles) high.

SOURCE: NASA/JPL PIA09176

This radar image, obtained by Cassini's radar instrument during a near-polar flyby on Feb. 22, 2007, shows dunes surrounding a bright feature on Saturn’s moon Titan. Dunes have been previously seen on Titan, so far concentrated near the equator. They are thought to be composed of small hydrocarbon or water ice particles-- probably about 250 microns in diameter, similar to sand grains on Earth. These are formed into dunes by the prevailing west-to-east surface winds. Because of the shape and length of the dunes, they are probably "longitudinal" (lying in the same direction as the average wind) rather than transverse dunes, which form across the wind and are more common on Earth.

There are several kinds of interaction between the dunes and the brighter features in this image. At the left, the dunes seem to be covering the bright material, while at the center and right, they seem to be terminated against it. At the lower center and lower right, they flow around it (see also PIA08738 and PIA08454). These various interactions will help us to determine the nature of both of these features.

This image was taken in synthetic aperture mode at 700-meter (2,300-foot) resolution. North is toward the left. The image is centered at about 3.5 degrees south latitude and 37.3 degrees west longitude.

SOURCE: NASA/JPL PIA09181

This radar image, obtained by Cassini's radar instrument during a near-polar flyby on Feb. 22, 2007, shows a big island smack in the middle of one of the larger lakes imaged on Saturn's moon Titan. This image offers further evidence that the largest lakes are at the highest latitudes.

The island is about 90 kilometers (62 miles) by 150 kilometers (93 miles) across, about the size of Kodiak Island in Alaska or the Big Island of Hawaii. The island may actually be a peninsula connected by a bridge to a larger stretch of land. As you go farther down the image, several very small lakes begin to appear, which may be controlled by local topography.

This image was taken in synthetic aperture mode at 700 meter (2,300 feet) resolution. North is toward the left. The image is centered at about 79 north degrees north and 310 degrees west.
 

SOURCE: NASA/JPL PIA09180

This radar image of Titan shows a semi-circular feature that may be part of an impact crater. Very few impact craters have been seen on Titan so far, implying that the surface is young. Each new crater identified on Titan helps scientists to constrain the age of the surface.

Taken by Cassini's radar mapper on Jan. 13, 2007, during a flyby of Titan, the image swath revealed what appeared to be the northernmost half of an impact crater. This crater is roughly 180 kilometers (110 miles) wide. Only three impact craters have been identified on Titan and several others, like this one, are likely to also have been caused by impact. The bright material is interpreted to be part of the crater's ejecta blanket, and is likely topographically higher than the surrounding plains. The inner part of the crater is dark, and may represent smooth deposits that have covered the inside of the crater.

This image was taken in synthetic aperture mode and has a resolution of approximately 350 meters (1,150 feet). North is toward the top left corner of the image, which is approximately 240 kilometers (150 miles) wide by 140 kilometers (90 miles) high. The image is centered at about 26.5 degrees north and 9 degrees west. 

SOURCE: NASA/JPL PIA09175

The three mosaics shown here were composed with data from Cassini's visual and infrared mapping spectrometer taken during the last three Titan flybys, on Oct. 28, 2005 (left image), Dec. 26, 2005 (middle image), and Jan. 15, 2006 (right image).

These false-color images were constructed from images taken at the following wavelengths: 1.6 microns (blue), 2.01 (green), and 5 microns (red).

The viewing geometry of the December flyby is roughly on Titan's opposite hemisphere from the flybys in October and January. There are several important features to note in the images. The first is that the south polar cloud system was very bright during the December flyby, while during the October and January flybys, it is barely visible, indicating that the atmosphere over Titan's south pole is very dynamic.

In the December (middle) mosaic, a north polar hood that is bright at 5 microns is visible. Its composition is unknown. The north polar hood is barely seen in the October (left image) and January (right image) data. Visible in the October and December images just south of the equator is Tui Reggio, a region nicknamed the “chevron.” This region is very bright at 5 microns and is among the brightest features on Titan at that wavelength. Tui Reggio is thought to be a surface deposit, probably of volcanic origin, and may be water and/or carbon dioxide frozen from the vapor. The January flyby data show that the western margins of Tui Reggio have a complex flow-like character consistent with eruptive phenomena.

SOURCE: NASA/JPL PIA02145

Saturn's orange moon Titan has hundreds of times more liquid hydrocarbons than all the known oil and natural gas reserves on Earth, according to new data from NASA's Cassini spacecraft. The hydrocarbons rain from the sky, collecting in vast deposits that form lakes and dunes. artist concept of terrain on Titan Image right: An artist's imagination of hydrocarbon pools, icy and rocky terrain on the surface of Saturn's largest moon Titan. Image credit: Steven Hobbs (Brisbane, Queensland, Australia).

The new findings from the study led by Ralph Lorenz, Cassini radar team member from the Johns Hopkins University Applied Physics Laboratory, Laurel, Md., are reported in the Jan. 29 issue of the Geophysical Research Letters.

"Titan is just covered in carbon-bearing material -- it's a giant factory of organic chemicals," said Lorenz. "This vast carbon inventory is an important window into the geology and climate history of Titan."

At a balmy minus 179 degrees Celsius (minus 290 degrees Fahrenheit), Titan is a far cry from Earth. Instead of water, liquid hydrocarbons in the form of methane and ethane are present on the moon's surface, and tholins probably make up its dunes. The term "tholins"was coined by Carl Sagan in 1979 to describe the complex organic molecules at the heart of prebiotic chemistry.

Cassini has mapped about 20 percent of Titan's surface with radar. Several hundred lakes and seas have been observed, with each of several dozen estimated to contain more hydrocarbon liquid than Earth's oil and gas reserves. The dark dunes that run along the equator contain a volume of organics several hundred times larger than Earth's coal reserves.

Proven reserves of natural gas on Earth total 130 billion tons, enough to provide 300 times the amount of energy the entire United States uses annually for residential heating, cooling and lighting. Dozens of Titan's lakes individually have the equivalent of at least this much energy in the form of methane and ethane.

"This global estimate is based mostly on views of the lakes in the northern polar regions. We have assumed the south might be similar, but we really don't yet know how much liquid is there," said Lorenz. Cassini's radar has observed the south polar region only once, and only two small lakes were visible. Future observations of that area are planned during Cassini's proposed extended mission.

Scientists estimated Titan's lake depth by making some general assumptions based on lakes on Earth. They took the average area and depth of lakes on Earth, taking into account the nearby surroundings, like mountains. On Earth, the lake depth is often 10 times less than the height of nearby terrain.

"We also know that some lakes are more than 10 meters or so deep because they appear literally pitch-black to the radar. If they were shallow we'd see the bottom, and we don't," said Lorenz.

The question of how much liquid is on the surface is an important one because methane is a strong greenhouse gas on Titan as well as on Earth, but there is much more of it on Titan. If all the observed liquid on Titan is methane, it would only last a few million years, because as methane escapes into Titan's atmosphere, it breaks down and escapes into space. If the methane were to run out, Titan could become much colder. Scientists believe that methane might be supplied to the atmosphere by venting from the interior in cryovolcanic eruptions. If so, the amount of methane, and the temperature on Titan, may have fluctuated dramatically in Titan's past.

"We are carbon-based life, and understanding how far along the chain of complexity towards life that chemistry can go in an environment like Titan will be important in understanding the origins of life throughout the universe," added Lorenz.

Cassini's next radar flyby of Titan is on Feb. 22, when the radar instrument will observe the Huygens probe landing site. 

SOURCE: NASA/JPL

Using its radar system, the Cassini spacecraft has imaged new lakes on Titan.

The large dark patch seen on this image, at high latitudes surrounding Titan's north pole, is most likely a hydrocarbon lake. Several dark channels can be seen; the longest one at the left meanders over almost 100 kilometers (62 miles), and appears to drain into the lake. Some dark channels are remarkably straight, suggesting possible faulting in the subsurface. The bright landforms jutting into the lake indicate that old, eroded landforms may have flooded. For a different radar view from the same flyby see http://www.nasa.gov/mission_pages/cassini/multimedia/pia01943.html.

This radar image was acquired by the Cassini radar instrument in synthetic aperture mode on Oct. 9, 2006. The image is centered near 73 degrees north latitude, 343 degrees west longitude, and measures about 300 kilometers by 140 kilometers (190 miles by 90 miles). Smallest details in this image are about 500 meters (1,640 feet) across. 

SOURCE: NASA/JPL PIA01942

This radar image of Titan's well-known dunes is distinctive because it may show an age relationship between different classes of features on the surface of this frigid world.

Taken by Cassini's radar mapper on Jan. 13, 2007, during a flyby of Titan, three kinds of terrain can be seen. Throughout the image, the fine striping has been identified as dunes, possibly made from organic material and formed by wind activity. Dunes are a common landform on Titan (see PIA09111 and PIA08738). The bright material at the lower right of the image is interpreted as being topographically higher than the dunes that go around it, and several circular features seen at the top center may be craters that are slowly being buried by the dunes. Since the dunes seem to lie over the craters, the dune activity probably occurred later in time.

This image was taken in synthetic aperture mode and has a resolution of approximately 350 meters (1,150 feet). North is toward the top left corner of the image, which is approximately 160 kilometers (100 miles) long by 150 kilometers (90 miles) wide.

SOURCE: NASA/JPL PIA09115

This lake is part of a larger image taken by the Cassini radar instrument during a flyby of Saturn's moon Titan on Sept. 23, 2006. It shows clear shorelines that are reminiscent of terrestrial lakes. With Titan's colder temperatures and hydrocarbon-rich atmosphere, however, the lakes likely contain a combination of methane and ethane, not water.

Centered near 74 degrees north, 65 degrees west longitude, this lake is roughly 20 kilometers by 25 kilometers (12 to 16 miles) across. It features several narrow or angular bays, including a broad peninsula that on Earth would be evidence that the surrounding terrain is higher and confines the liquid. Broader bays, such as the one seen at right, might result when the terrain is gentler, as for example on a beach. 

SOURCE: NASA/JPL PIA08741

This lake is part of a larger image taken by the Cassini radar instrument during a flyby of Saturn's moon Titan on Sept. 23, 2006. It shows clear shorelines that are reminiscent of terrestrial lakes. With Titan's colder temperatures and hydrocarbon-rich atmosphere, however, the lakes likely contain a combination of methane and ethane, not water.

Centered near 74 degrees north, 65 degrees west longitude, this lake is roughly 20 kilometers by 25 kilometers (12 to 16 miles) across. It features several narrow or angular bays, including a broad peninsula that on Earth would be evidence that the surrounding terrain is higher and confines the liquid. Broader bays, such as the one seen at right, might result when the terrain is gentler, as for example on a beach. 

SOURCE: NASA/JPL PIA08741

This Cassini radar image shows two lakes "kissing" each other on the surface of Saturn's moon Titan.

The image from a flyby on Sept. 23, 2006, covers an area about 60 kilometers (37 miles) wide by 40 kilometers (25 miles) high.

This pass was primarily dedicated to the ion and neutral mass spectrometer instrument, so although, the volume of radar data was small, scientists were amazed to see Earth-like lakes. With Titan's colder temperatures and hydrocarbon-rich atmosphere, however, the lakes likely contain a combination of methane and ethane, not water.

In this image, near 73 degrees north latitude, 46 degrees west longitude, two lakes are seen, each 20 to 25 kilometers (12 to 16 miles) across. They are joined by a relatively narrow channel. The lake on the right has lighter patches within it, indicating that it may be slowly drying out as the northern summer approaches. 

SOURCE: NASA/JPL PIA08740

This image is a composite of several images taken during two separate Titan flybys on Oct. 9 (T19) and Oct. 25 (T20).

The large circular feature near the center of Titan's disk may be the remnant of a very old impact basin. The mountain ranges to the southeast of the circular feature, and the long dark, linear feature to the northwest of the old impact scar may have resulted from tectonic activity on Titan caused by the energy released when the impact occurred.

The Oct. 9 images form the background globe for context, and the most recent images from the Oct. 25 flyby are overlaid. The Oct. 9 images were taken at an average distance of about 30,000 kilometers (18,000 miles). The Oct. 25 images were taken at a distance of 12,000 kilometers (7,200 miles). The images were taken at wavelengths of 1.3 microns shown in blue, 2 microns shown in green, and 5 microns shown in red. 

SOURCE: NASA/JPL PIA09034