Saturn's Moon Titan has a strange ice formation Thousands of kilometers long

The strange moon of Saturn Titan Hides a lot of his secrets behind layers and layers of thick mist, but scientists have now looked through the haze in a new way – and spotted a huge expanse of ice water to boot.

This ice block extends over almost half the circumference of Titan. This feature was a surprise companion to the patches of water ice that scientists are supposed to find, and they do not know exactly what kind of geological feature this might indicate. The search is based on data collected by Cassini spacecraft from NASA, who spent 13 years studying the Saturn system and making more than 100 flyovers of the huge moon before self-destruct in September 2017.

"This is a good example of how we are really succeeding in harnessing this amazing data from Cassini to get new results," said Jani Radebaugh, planetary scientist at Brigham Young University's 39, Utah, who did not participate in the new research. .com. "We are far from having figured out Titan as far as possible with Cassini."

Related: Moon Saturn Titan may have 'ghost lakes' and caves

Scientists want to understand Titan because its features bring a disturbing twist to the planet we know and love so much. The moon has a thick and nitrogen-rich atmosphere, and liquids fall on its surface to fill up lakes and seas. But these liquids are organic compounds falling on a surface consisting partly of ice water. It's strange. It's also a struggle to study because all these strange things get in the way.

"What interests us is what's going on beyond this soft global snowfall of organic matter?" Said Radebaugh. "It can be very difficult to see through this layer to see what happens."

This is where the technique used in the new paper comes into play. The new research uses a statistical approach called principal component analysis, which allows scientists to look beyond the most dominant features in the data – such as blur – and get much smaller signatures that would otherwise be missed – like frozen water. In the new study, scientists applied this technique only to the Titan band located between 30 degrees north and south latitude.

"The idea was to say" Let's try to have a global idea of ​​the distribution of ice on the surface compared to the amount of organic matter on the surface ". , said author Caitlin Griffith, specialist in planetary sciences at the University of Arizona. said Space.com. "We needed a method to measure these very very weak features and try to extract information from them."

Principal component analysis has allowed Griffith and his colleagues to do just that. "We are looking for some very subtle features hidden behind larger features," Griffith said. "It really works like a charm, which allowed us to get very detailed information about these very weak features" – as where the water ice was visible on the surface.

(Image: © NASA / JPL / University of Arizona)

Some of the areas where the team discovered water ice corresponded to what scientists expected – around this large cryovolcano which once poured liquid water on the surface of Titan and around impact craters where meteorites sink into the surface of the moon. But no one expected the huge ice belt – 6,300 kilometers long – to appear in the same analysis.

"There is really nothing that tells us that it should be made of water ice even if you look at the landscape," Radebaugh said. "Nothing really says that it's different from everything else."

Griffith said that she did not yet know what the massive ice line represented, which she compared to a scar. More research is needed to determine what left the ice found on Titan's surface. "It's a great feature that tells us something about how Titan was in the pastbut we do not really know what it is, she said. I think at the moment, it basically tells us that it's complicated, that the surface is quite complicated. "

Radebaugh stated that, from his point of view, outside of the team, it would appear that this feature could be the result of a major fault-cracking event that would have raised a bedrock portion of ice water and would have left it uncovered. If that turns out to be the case, the feature could offer a window on a Titan layer that has not yet been in the spotlight.

"tectonism In some ways, Titan has taken a step back, just because we're seeing all these surface processes – fluid flow, erosion, wind deposits, and so on. Said Radebaugh. process, these things are somehow in your face. "

But it's not because something is hidden that it deserves to stay that way, she added. "We must remember that there is also a very interesting, possibly active lithosphere."

The research is described in a document published today (April 29) in the journal Nature Astronomy.

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