Mysterious features spotted on Titan reveal the moon's seasonal changes

Image: NASA/JPL-Caltech
June 2014

At first glance, Titan has little in common with Earth. The largest moon of Saturn, temperatures on Titan's surface dip nearly 300 F below zero, its seas slosh with liquid methane, and its sky is a murky shade of creamsicle.

And yet, fresh analysis of mysterious features spotted on the moon indicates that it experiences one of the same global processes that is important here on Earth.

In a study published in the latest issue of Nature Geoscience, scientists operating the Cassini satellite, including Stanford's Howard Zebker, present evidence that Titan has seasonal cycles analogous to Earth's, and that the moon's surface conditions change as the Titan year unfolds.

The Cassini satellite has been orbiting Saturn and its moons since 2004. Zebker, a professor of electrical engineering and of geophysics, is one of the lead scientists operating the spacecraft's radar instruments. Radar is critical for studying Titan in particular because the moon's atmosphere is typically too cloudy and thick for optical instruments to see through easily.

During five fly-bys of Titan's Ligeia Mare – a liquid methane sea larger than Lake Superior – the scientists noticed bright features that appeared and changed shape on the sea's surface. After ruling out a technical glitch or an exotic artifact of radar scattering, the group focused on three causes most likely for the phenomena.

"We are driven to use our imaginations and picture what could be happening on the sea to produce a transient feature," Zebker said.

For the full story, visit Stanford News.