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The discovery of enigmatic dust storms on Titan means that the most exotic moon of the Solar System has taken hold of it.
If I could visit a celestial body in the solar system, it would have to be Titan. This large moon presents an active geology and dynamic atmospheric processes that would really be something to see.
Measaning nearly 5,200 km in diameter, Titan is the second largest moon in the solar system and the largest natural satellite of Saturn. It is also the only moon that holds the atmosphere of any substance: a thick mist consisting mainly of nitrogen. Titan is also the only celestial body other than the Earth capable of maintaining a stable liquid on the surface. But the many lakes and rivers of this moon are not filled with water – they are filled with a harmful mixture of oil, consisting of methane, ethane, and other liquid hydrocarbons. It has been observed that these seas of liquefied natural gas form waves and produce enigmatic "magic islands" that sometimes appear above the surface and then mysteriously disappear. If that is not enough, Titan presents a unique meteorological cycle in which the hydrocarbon molecules evaporate, condense in clouds (called convection process), then rush to the surface. So yes, it literally rains oil on Titan, and sometimes it snows, in the form of benzene.
A new study published this week in Nature Geoscience reveals another amazing feature of the Titan: equatorial dust storms. This makes Titan one of the three celestial bodies of the solar system to produce dust storms, Earth and Mars being the other two.
This discovery was made possible by the recent and large Cassini spacecraft, which used its infrared camera to detect unusual equatorial clearings in 2009 and again in 2010. The size of the lights ranged from 69,500 square miles to 180,000 km2. square miles (420,000 square kilometers), an area larger than all over Germany and on a celestial body 2.5 times smaller than the Earth.
At first, astronomers thought that the spots that appeared during Titan's northern spring equinox were just clouds of methane, but other research has revealed something much more interesting.
"From what we know about the formation of clouds on Titan, we can say that these methane clouds in this region and at this time of the year are not physically possible", said Sebastien Rodriguez, senior author of the new journal and astronomer at the University. Paris Diderot, France, said in a statement. "The convective methane clouds that can develop in this area and during this period would contain huge droplets and must be at a very high altitude, well above the 10 kilometers that the modeling tells us. "
At the same time, equatorial lightening would probably not be surface elements, such as frozen methane or frozen lava (yes, you read that right – Titan has ice volcanoes). If this were the case, these surface spots would have a different chemical signature and would remain visible much longer than Cassini had observed; the characteristics were transient and lasted from 11 hours to 5 weeks.
Using computer models, Rodriguez and his colleagues concluded that the characteristics were atmospheric in nature, occurring very close to the surface and probably consisting of a thick layer of tiny solid organic particles (on Titan, organic methane, and they grow up enough to fall back to the surface). In addition, the bright spots occurred on Titan's equatorial dune fields, which clearly indicates that the spots were dust clouds expelled from the dunes.
Interestingly, Huygens Probe of the European Space Agency, who landed on the surface of Titan in 2005, raised organic dusts during his landing because of his powerful aerodynamic wake, according to Rodriguez.
"But what we have seen here with Cassini is on a much larger scale," he said. "The wind speed near the surface required to raise such a large amount of dust should be very high, about five times the average speed estimated by Huygens measurements near surface and climate. models."
In terms of next steps, researchers would like to know if these strong winds are agitating the sand, in addition to organic particles. If this is the case, Titan presents a complex global cycle similar to that observed on Earth and Mars. Titan is a real paradox: a celestial body with obvious comparisons to our planet, but profoundly alien at the same time.
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