Dust storms spotted on Titan
Scientists reviewing Cassini data have identified dust storms for the first time of Saturn’s moon Titan.
When Rodriguez and his team first spotted three unusual equatorial brightenings in infrared images taken by Cassini around the moon’s 2009 northern equinox, they thought they might be the same kind of methane clouds; however, an investigation revealed they were something completely different. “From what we know about cloud formation on Titan, we can say that such methane clouds in this area and in this time of the year are not physically possible,” said Rodriguez. “The convective methane clouds that can develop in this area and during this period of time would contain huge droplets and must be at a very high altitude — much higher than the 6 miles (10 kilometers) that modeling tells us the new features are located.”
The researchers were also able to rule out that the features were actually on the surface of Titan in the form of frozen methane rain or icy lavas. Such surface spots would have a different chemical signature and would remain visible for much longer than the bright features in this study, which were visible for only 11 hours to five weeks.
In addition, modeling showed that the features must be atmospheric but still close to the surface — most likely forming a very thin layer of tiny solid organic particles. Since they were located right over the dune fields around Titan’s equator, the only remaining explanation was that the spots were actually clouds of dust raised from the dunes.
Obviously there are large uncertainties here. Nonetheless, the conclusion is a reasonable one, as it is expected that such dust storms would occur on Titan.
Posted just outside Zion National Park in the town of Springdale.
Scientists reviewing Cassini data have identified dust storms for the first time of Saturn’s moon Titan.
When Rodriguez and his team first spotted three unusual equatorial brightenings in infrared images taken by Cassini around the moon’s 2009 northern equinox, they thought they might be the same kind of methane clouds; however, an investigation revealed they were something completely different. “From what we know about cloud formation on Titan, we can say that such methane clouds in this area and in this time of the year are not physically possible,” said Rodriguez. “The convective methane clouds that can develop in this area and during this period of time would contain huge droplets and must be at a very high altitude — much higher than the 6 miles (10 kilometers) that modeling tells us the new features are located.”
The researchers were also able to rule out that the features were actually on the surface of Titan in the form of frozen methane rain or icy lavas. Such surface spots would have a different chemical signature and would remain visible for much longer than the bright features in this study, which were visible for only 11 hours to five weeks.
In addition, modeling showed that the features must be atmospheric but still close to the surface — most likely forming a very thin layer of tiny solid organic particles. Since they were located right over the dune fields around Titan’s equator, the only remaining explanation was that the spots were actually clouds of dust raised from the dunes.
Obviously there are large uncertainties here. Nonetheless, the conclusion is a reasonable one, as it is expected that such dust storms would occur on Titan.
Posted just outside Zion National Park in the town of Springdale.