The topography of Titan, the largest of Saturn's moon, seems serene in the images of the Cassini mission, but the lakes of liquid methane that hit the landscape were probably formed by explosive nitrogen and pressurized just below the crunchy surface of the moon, according to one research published September 9 in Nature Geoscience.
"Titan has a very distinctive topography. Its lakes show different types of shapes and in some cases sharp ridges, "said the co-author Jonathan Lunine, David C. Duncan Professor of Physical Sciences and President of the Department of Astronomy.
An international group of scientists, led by Giuseppe Mitri of the University of Annunzio in Italy, examined the lakes on the surface of Titan that had steep edges and craters, raised edges and bastions. Some of the steep ridges rise far above the natural level of the liquid sea of the moon.
"Either you need explosive gas or a gas that builds up enough pressure to burst like a cork from a bottle of champagne. On Titan, there is nothing that creates a fiery explosion because that moon has no free oxygen, "said Lunine." Therefore, we argue that a pressurized explosion model is a better model for these types of lakes . The craters are created and filled with liquid methane. "
In addition to the Earth, Titan is the only other body in the solar system with a stable liquid – in this case, methane – on its surface. The atmosphere of Titan is full of vaporized nitrogen.
In Titan's geophysical history, that moon has seen eras when methane runs out, leaving a nitrogen atmosphere. Nitrogen cools, Lunine said, producing a liquid nitrogen rain in its icy climate, which then collects in pockets under Titan's crust.
While Titan is far from the sun, a slight amount of geological heating could occur which causes this gas to explode under pressure, exploding on the surface. In the natural cyclical process of the moon, liquid methane returns and fills the craters to create lakes.
The images for this research were collected from the radar data of the NASA Cassini the last fly-by of Titan's mission, a few months before the last spacecraft dive into Saturn two years ago.
Lunine noted that explosions under pressure occur elsewhere in the solar system. On the moon of Neptune Triton, during the Voyager II mission in 1989, scientists saw this phenomenon in a large polar cap composed of nitrogen.
"We saw these large nitrogen deposits with strips of black that looked like cigarette burns on nitrogen ice," he said. "It was the dust under the nitrogen that was heated by the sun, allowing the nitrogen to explode to the outside."
In addition to Mitri and Lunine, other co-authors of "Possible explosion crater Origin of small lake basins with raised edges on Titan, "Post-doctoral researchers were Valerio Poggiali at Cornell and Marco Mastrogiuseppe at the California Institute of Technology. NASA provided funding for this research.
/ Public publication. View in full Here.