NASA’s Cassini mission to Saturn discovered clouds of methane moving across the northern regions of Saturn’s largest moon Titan late October. The clouds were on the surface around 11 hours of a movie sequence and then faded away. Cassini has been studying Saturn and its moons in detail, particularly Titan which is similar to Earth.

The images, captured on October 29 and 30, show how several sets of clouds formed, moved over the moon’s surface and then disappeared. Cassini mission used a movie sequence to study the methane clouds with one frame taken every 20 minutes. The movie sequence features long clouds streaks that were between 46 and 55 degrees north latitude.  The clouds seen in October are not the first ones to be observed in the region. Individual streaks have appeared and faded in the area.

Cassini, Saturn

The Cassini mission has calculated that the clouds move at a speed of about 14 to 22 miles per hour, which is equivalent to 7 to 10 meters per second. Image credit: NASA.

The movie was shot using Cassini narrow-angle camera using infrared filters to make the surface and tropospheric methane clouds visible, said Cassini mission to Saturn official website.

Time-lapse movies allow scientists to observe the dynamic of clouds on Titan’s surface better. The movie shows how they are formed, how they move and how they disappear. Time-lapse videos also help distinguish between noise in images and faint clouds or fog, providing more substantial evidence on Titan’s climate.

NASA explains that models of Titan’s climate have predicted more cloud activity in the moon’s northern region during the planet’s summer. The cloud activity reveals that scientists have not figure out how seasons work in Titan and more research needs to be done before understanding how climate works in Saturn’s largest moon. The mission will continue to observe Titan’s weather next year during the summer solstice in the moon’s northern hemisphere.

In 2016, the Cassini mission has intermittently observed clouds forming and moving in the northern mid-latitudes of Titan and the north polar region of the moon. The latter is an area that contains numerous methane and ethane lakes and seas, which could be responsible for the formation of the methane clouds.

The obstacle to understanding clouds activity on Titan is the mission develop for 2016 observation and monitoring that takes short snapshots with days and even weeks apart. But the recent images provided Cassini a better opportunity to study short-term clouds dynamics, letting scientist progress faster on theories regarding Titan’s seasons.

Cassini: An old mission that has given us almost all that it is known about Saturn and its largest moon Titan

The Cassini mission was launched October 15, 1997. Cassini orbits Saturn to study the planet and its moons. In 2005, the Huygens probe landed successfully on Titan to better study the Earth-like moon.

Before Cassini, all it was known about Titan was that the moon was the size of Mercury and that it had an atmosphere rich in nitrogen. Now the mission has managed to gather and produce incredible amounts of information about Titan. The mission has mapped Saturn’s largest moon, discovered liquid seas made of methane and ethane, and has some knowledge of Titan’s atmospheric reactions.

Source: Cassini mission to Saturn