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Saturn moon map reveals seas, underground rivers

An image mosaic of Titan's northern hemisphere from NASA's Cassini mission.
A mosaic image of Titan's liquid methane and ethane seas. Photo: JPL-CALTECH / NASA / ASI / USGS

The most complete map to date of Saturn’s moon Titan reveals a mountainous world with a network of liquid methane and ethane lakes and seas connected by underground rivers, writes Lisa Grossman for Science News. Scientists already knew that Titan had something like Earth’s water cycle, but with methane. This is the latest finding from the Cassini mission to show the startling geological complexity of the hazy, gassy moon.

Why it matters: Scientists are very interested in Titan’s geology because they believe the hydrocarbon-rich planet has the potential to support some form of life. An interconnected water system, like the one on Earth, could influence the way any such life would develop. “Looking for actual evidence that the lakes could be communicating was a fundamental question from Cassini,” study coauthor Alexander Hayes tells Grossman, “This is the final paper that gives the best evidence that it exists.”

What they did: When Cassini flew over Titan 13 years ago, the robot scanned the planet and measured elevation. They used radar to identify lakes, seas and mountain ranges.

What they found: When they analyzed the altitude of Titan’s largest bodies of liquid methane, they found they were all at about the same level, like sea level on Earth. For them to stay level, they need to be connected. The map also details mountain ranges across the planet, including the southern hemisphere, and reveals high-altitude dry lakebeds that could be sinkholes or the remnants of volcanoes.

What’s next: The map, which was published December 2 in the journal Geophysical Research Letters, will likely be used by other scientists studying the Saturnian moon’s geology. “Within hours of the paper actually being available online, people we’ve never collaborated with started contacting [Hayes’ co-author, Paul Corlies] to ask how to get the data,” Hayes told Grossman.

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