0206 GMT April 21, 2019
Using data from NASA's Cassini spacecraft — in orbit around Saturn from July 2004 to September 2017 — scientists found what they believe to be giant dust storms around the planet's equatorial regions, cbc.ca reported.
Titan is the second-largest moon in our solar system. Of all the more than 150 known moons in Earth's celestial backyard, it is the only one with a substantial atmosphere, made up of mostly nitrogen, like Earth's. It also has clouds, rivers and lakes. But instead of water, they contain hydrocarbons like methane and ethane, chemicals found in gasoline.
And at first, that's what researchers thought they were looking at when they scanned the data collected in 2009. They thought the brightening region were clouds of methane.
Sebastien Rodriguez, an astronomer at Paris Diderot University in France and lead author of a study on the phenomenon published in Nature Geoscience, said, "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."
Aside from the unlikelihood that clouds would develop around the equator during this time of year — the moon's northern equinox — another reason for their conclusion was that the formation occurred far lower in the atmosphere than clouds would.
They also ruled out frozen methane rain or icy lavas. That left them with just one explanation: Dust.
They'd seen dust on the surface of Titan before. In January 2005, the Huygens probe, which was part of the Cassini mission, landed on the moon's surface, kicking up a small amount of organic dust.
"But what we spotted here with Cassini is at a much larger scale." Rodriguez said.
"The near-surface wind speeds required to raise such an amount of dust as we see in these dust storms would have to be very strong — about five times as strong as the average wind speeds estimated by the Huygens measurements near the surface and with climate models."