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January 26, 2010

Weird Hills on the Surface of Titan

Titan is one of the one of the most exciting places in our solar system. This moon of Saturn has liquid methane playing the role of water on its surface, and water ice playing the role of solid rock. We are just beginning to understand the dynamics at work on this moon, in part because it is shrouded in a thick methane atmosphere. This image was taken on December 28th, 2009 and is giving sicentists new puzzle to solve.

The lines you see in the lower left of the image are rifts similar to features called corona on Venus. On Venus, we think they are caused by heat within the planet that puts stress on the rock. Straight features like this could also be created by surface activity like wind or rainfall.

The star-shaped feature to the right also points to some sort of activity happening in this area. “This star-shaped pattern of the hills indicates something significant happening in the middle of the star,” said Steve Wall of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., a Cassini scientist on the radar team. “It might be caused by tectonic forces, such as the forces that pull the crust of a planet apart, or rainfall that leads to erosion, or an ice intrusion like a dike.”

Scientists don't have any answers yet, but either answer would be exciting. If this was caused by rain, it gives us a better understanding of how liquid methane shapes the surface of Titan. If on the other hand it is caused by some sort of internal heat, it raises all new questions on what the inside of Titan is like. We will just have to wait as Cassini continues to unveil this exciting world.

Image Credit: NASA/JPL