A mysterious ice band stretches for thousands of miles across Saturn's moon

Saturn has many moons, but Titan is of particular interest to scientists for many reasons. There is a thick atmosphere, liquid bodies on the surface and adverse weather conditions. Scientists from the University of Arizona, who study atmospheric processes on Titan, report that they have stumbled upon a yet unknown global feature: an ice ribbon that envelops the planet on more than 40 % of its circumference.

Titan's atmosphere is mainly composed of nitrogen, but there are also traces of methane and other molecules. Solar radiation breaks down methane molecules, which are deposited on the planet in the form of organic sediments. This naturally eliminates methane from the atmosphere, but levels remain constant. The study conducted by Caitlin Griffith of the lunar and global laboratory of the AU sought to find a source of methane supply.

In the past, researchers have postulated that a form of cryovolcanism could be responsible for releasing methane from underground reservoirs. The only confirmed source of methane is the evaporation of the world's hydrocarbon lakes, but that would not represent all the atmospheric methane. The team analyzed half of Titan's surface in the hope of finding traces of the cryovolcano, but it remained empty. They found something else in a region called Sotra.

The Titan ice band (blue-green) spans 4,000 miles.

The team discovered a strip of ice in the water by evaluating the Sotra scans conducted by NASA's Cassini spacecraft. What initially appeared to be a local feature turned out to be the beginning of an ice corridor that extends over 40% of the moon's perimeter. The researchers used a technique called Principal Component Analysis (PCA). Rather than searching for important features pixel by pixel, PCA allows scientists to detect trends in landscapes. Applying this to Titan, the data showed the band of water ice around the equatorial region of the moon.

This ice corridor does not appear to correlate with existing geological features, and is irregular at the surface. This indicates that the ice may be eroding. Thus, the ice could have settled at a given moment when Titan was still geologically active during a major cryovolcanic event. This does not tell us if the same event or band of ice is related to Titan's methane cycle, but this use of the PCA could lead to many more discoveries on Saturn's largest moon.

Now read: