Scientists working with the data of the spacecraft Cassini, came to the conclusion that the surface of lakes and seas of Titan can decorate hydrocarbon ice floes. The presence of the latter allows to explain the strange reflectivity of a surface of this moon of Saturn.

The formation of hydrocarbon ice on the surface of Titan in the view of the artist (image from NASA / JPL-Caltech / USGS).

In addition, as noted study co-author Jonathan Lunin of Cornell University (USA), on the border of liquid and solid media can be a special chemical reactions, which open up interesting prospects for the emergence of exotic life forms. Probably, these processes have played an important role in the emergence of life on Earth.

Titan is the only body in the Solar system besides Earth with a stable liquid on the surface. The only difference is that here the water, and there ethane, methane and other hydrocarbons. This circumstance does not upset specialists, as ethane and methane organic molecules that can serve as building blocks for more complex chemistry that leads to life. And if you believe Cassini, the Northern hemisphere of Titan is covered by a huge seas, and in the southern lakes.

Solid methane denser liquid, so still no one thought to assume the presence of ice on the surface of these basins. But in the new model takes into account the interaction between the lakes and the atmosphere, which leads to different composition of ice (otherwise they simply drowned least), temperature changes and the formation of nitric pockets. It turned out that winter ice could swim in lakes and seas of Titan at temperatures below the freezing point of methane (90,4 K)if it at least 5% of "air" (in the atmosphere of Titan are much more nitrogen and almost no oxygen). By the way, this is true for the part of young sea ice on Earth.

If the temperature drops by only a few degrees, the ice is sinking because of the relative share of nitrogen in liquid compared with a solid body. If temperatures are close to freezing point of methane, some of the ice kept on the surface and gradually freeze together, just as it happens with young ice of the Arctic.

In the color of ice, scientists have not understood. Most likely, it is a colorless, as on Earth, but with a reddish-brown tone characteristic of the atmosphere of Titan.

Radar Cassini will check this model by observing how changing the reflectivity of the surface of lakes and seas. It should be taken into account that in the spring of Northern lakes of Titan will be brighter, as with depths will rise sunken previously blocks of ice. With further warming, they will fade again.

The results will be published in the journal Icarus.