Saturn’s Largest Moon Titan Battered By Extreme Methane Rainstorms, Study Reveals

New research suggests that Saturn’s largest moon, Titan, is the site of some intense methane rainstorms. And while they may not take place too often in terms of Earth years, astronomers have discovered that the storms are more frequent than originally expected.

Throughout the course of NASA’s recently-concluded Cassini mission, Titan was one of the more extensively studied moons of Saturn. The space agency wrote in 2016 that Titan’s atmosphere is similar to Earth’s atmosphere in the sense that its nitrogen content is estimated to be over 95 percent. But while Earth has enough oxygen to definitely sustain life, the rest of Titan’s atmosphere is mostly made up of trace amounts of methane and other gases. Saturn’s largest moon is also believed to have at least one methane-rich sea, including Ligela Mare, which was estimated to be as large as Lake Huron and Lake Michigan combined.

With Cassini having completed its “grand finale” last month, researchers are still studying Saturn and its moons, and in a paper dated October 9, a team of UCLA scientists took a look at Titan’s methane rainstorms, which were originally thought to come once per millennium. According to Astronomy Now, the researchers used computer modeling to conclude that the storms take place less than once per Titan year; as Titan’s year is equivalent to about 29.5 Earth years, that means they could be once- or twice-in-a-lifetime events by our standards. Still, the estimate represents a surprisingly quick timeframe in between methane storms.

Titan’s methane rainstorms result in massive floods in the moon’s otherwise desert-like terrain, as explained by senior author Jonathan Mitchell, who leads UCLA’s Titan climate modeling research group.

“The most intense methane storms in our climate model dump at least a foot of rain a day, which comes close to what we saw in Houston from Hurricane Harvey this summer.”

In relation to Mitchell’s comparison, UCLA graduate student and study lead author Sean Faulk added that Titan’s extreme methane rainstorms have a similar effect on the moon’s surface as intense rainstorms do on our planet’s own surface. That’s because heavy rainstorms can result in alluvial fans, which are cone-shaped geographical features formed from large flows of sediment that disperses into the lowlands. These features were also discovered on Titan, suggesting that they may have likely formed by heavy blasts of methane rain.

Scientists studying Saturn’s moon Titan find evidence intense methane rainstorms occur more frequently than expected https://t.co/y2fsZziCGv pic.twitter.com/2hfLUwTfVK

— Astronomy Now (@AstronomyNow) October 15, 2017

The alluvial fans are one of the more recent discoveries credited to NASA’s Cassini mission, and add to the eponymous spacecraft’s early discovery of vast sand dunes in Titan’s lower latitudes and bodies of liquid in higher latitudes. According to the UCLA team, the alluvial fans can mainly be found between 50 and 80 degrees latitude, or right around the centers of Titan’s northern and southern hemispheres, but closer to the poles than they are to the equator. Most of the fans are located at around 60 degrees latitude, which is where the methane rainstorms are believed to be at their most intense.

With its contrasting surface features, the researchers believe Titan’s methane rainstorms might not be as prominent in other parts of the moon, as the absence of rainfall allows for sand dunes to form, while precipitation helps erode land and fill lakes up with liquid. As for the reason why the storms take place, the team theorized that this could be a result of another contrast – the cold, wet higher altitude weather, and the drier, warmer lower altitude conditions.

[Featured Image by Manjik/iStock]