The spacecraft Huygens, which examined the Saturn moon Titan. Image: NASA, public domain
Reading With giant telescopes, US researchers have for the first time observed the formation of a storm on Saturn's moon Titan: they were able to watch the clouds spread over the celestial body. Now they finally have an explanation for the river and canal systems that were discovered in winter 2004 and that cross the surface of the Saturn moon. These are reminiscent of formations on earth, but remained a mystery to the researchers, as they lie in the equatorial region of the moon, where no traces of cloud formation found. The new images suggest the hypothesis that clouds are formed elsewhere and transported over vast distances to the equator. Titan orbits the planet Saturn, its year lasts 30 Earth years and its surface temperature is minus 180 degrees Celsius. Yet he is compared to the earth again and again, because he has an atmosphere that consists mostly of nitrogen. In addition, it has earth-like geological formations such as mountain ranges or dunes, and there is a weather event on the Saturn moon. What the earth is the water, the titanium is the hydrocarbon methane. It floats in the atmosphere in gaseous form, condenses, falls as rain and forms rivers and lakes. Due to the different temperature conditions, the methane is sometimes liquid, whereas water only occurs as ice. The weather on Titan is very enlightening for astronomers, because he and Earth are the only known celestial bodies on which such phenomena take place.

Titan is under constant observation of smaller telescopes. If something unusual is registered, are the bigger ones heading for it? and more expensive? like the Gemini telescope on the Mauna Loa in Hawaii. Emily Schaller, first author of the study, believed in a bad joke when, after two years of observation, she glanced into her telescope for her dissertation, in which nothing special was recorded: huge clouds had formed. As a result, the moon was examined by the Gemini for several weeks. The clouds lay above the area that corresponds to the tropics on Earth and released cloud fragments that spread through the atmosphere to the South Pole and from there to the equator. This clarifies how geological formations developed in these areas, which are very reminiscent of those formed by liquid water in our country, according to the researchers.

The clouds, transported over the planet, acted as condensation points for the formation of new clouds in the other regions. This is as if a huge storm over South Africa only days later cloud formation over the Antarctic and Indonesia caused, explains Schaller. Such a phenomenon has not been considered as an explanation of the surface structure of the titanium equatorial region. Although this has soil formations that must have been caused by a liquid, but is one of the driest areas of the moon itself.

Emily Schaller (University of Arizona, Tucson) et al .: Nature, Vol. 460, p. 873 ddp / science.de? Martina Bisculm advertisement

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