Titan is the largest moon of the planet, Saturn and as far as we know is the only natural satellite that possess a thick atmosphere. Another interesting fact about this moon is that it is the only other celestial object besides Earth that shows obvious signs of bodies of liquid on its surface.
Saturn VI, as it is often called, is one of very few moons, which can be called ‘planet-like’ (think of Pandora from Avatar) along with one of Jupiter’s moons, Europa. What makes Titan so planet-like? Well, it is about 50% larger than the Earths own moon and is about 80% more massive. Other factors that add to its chances for habitability are its surface features, some of which highly resemble our own, and of course the dense atmosphere mentioned earlier.
The moon itself is composed of mostly water ice and other rocky materials, making it a terrestrial object. However, its incredibly thick atmosphere kept astronomers from studying the surface more in depth until the Cassini orbiter and Huygens probe finally reached Saturn. The Huygens probe was plunged into Titans atmosphere, landing on the surface while the Cassini orbiter remained high above. Once on the surface Huygens began transmitting data back to Earth. This event was historic for a two reasons: 1) It would be the first chance NASA and their associates could investigate Titan further for surface bodies of water and 2) It was the first landing on a celestial body in the outer Solar System.
The mission was already a success when bodies of liquid hydrocarbons were found in Titan’s polar regions. As stated before, the satellite is the only other known object besides Earth known to have bodies of liquids on its surface. Other information gained was the moon’s surface’s youth however, there are several mountains present and there’s evidence of cryovolcanoes. Titan’s surface is relatively flat with very few impact craters, which suggests its young age.
Through the Huygens probe the atmosphere was discovered to consist mostly of nitrogen, with methane and ethane filled clouds along with nitrogen-reach smog. Titan’s climate coupled with frequent rain and winds has created surface features much like Earths, including sand dunes, rivers, lakes and seas (those being most likely made of methane or ethane). Also much like Earth the moon has seasonal weather patterns. The moon resembles a very young Earth with its nitrogen-based atmosphere and bodies of liquids, however its temperatures are far lower than Earth’s at around 290 degrees below 0 Fahrenheit.
Because it so resembles an immature Earth, Titan has been cited as a possible habitat for microbial extraterrestrial life. If there is no life on the surface then there is at least a prebiotic environment full of organic material, which could be the progenitor of future life. Researchers have also suggested Titan may hold an underground ocean that could sustain life, akin to the same theory of Jupiter’s Europa.
It is also thought that life may exist on Titan’s surface by using the liquid methane or ethane as its environment. Though some astronomers would consider this impossible, we only need to look at the bizarre life, which has formed on Earth, from tube worms surviving on the edges of volcanic vents or hairy crabs living almost two miles below the ocean surface.
Titan’s Surface Features
The surface of Titan consists of extremely flat smooth landscapes and also sections of extremely rough zones. As stated before, there are signs of cryovolcanoes and other volcanic activity across the complex terrain. Also present are long streaks across the soil, which appear to have been caused by fierce gusts of winds, which may have also caused Titan’s numerous sand dunes. Mountains dot the landscape reaching heights between 150 and 500 meters high.
From infrared imaging captured by the Cassini orbiter Titan’s topography is marked by wide regions of dark and bright terrain. An example of this is Xanadu, an area located at the equator that is about the size of Australia. It is marked by a convoluted region filled with hills and contains various valleys and canyons. Xanadu is crisscrossed in places by dark contours and snake-like features that resemble cliffs or crevices. These cracks and fissures might suggest tectonic activity is occurring, which also validates the theory Xanadu and other surface areas are geologically young. It has also been suggested that the contours may be channels that had been formed by flowing liquids.