They dot the bedrock of the Xanadu region

May 12, 2010 08:37 GMT  ·  By

According to a new series of observations conducted using the NASA Cassini spacecraft, it would appear that the Xanadu region of the Saturnine moon Titan is paved with sparkling crystal ice balls. The science team managing the long-lived space probe, which has been orbiting Saturn since July 1, 2004, says that the main factor that led to the development of these structures may have been flash floods in the area, which carried the ice from the higher regions of Xanadu in the bedrock on streams below. The conclusions are based on radar scattering patterns that Cassini produced of the area.

The researchers say that the crystal balls themselves have diameters ranging from a few centimeters to maybe even a few meters, and add that they cannot think of anything other than flash floods to explain how these peculiar structures appeared at the location. The group explains that its theory is also supported by the fact that water-ice bedrocks have been already identified as existing in the higher regions of Xanadu, which means that they are the most likely candidates for a source for the structures further downstream.

“What we believe happened in this area is a lot like what creates polished river rocks on Earth. Bouncing downstream smooths out the edges of rocks,” explains the lead author of the new study detailing the findings, Alice Le Gall. She is also a postdoctoral fellow at the Pasadena, California-based NASA Jet Propulsion Laboratory (JPL). Experts here manage the Cassini mission for the American space agency's Science Mission Directorate, in Washington, DC. ”It's been really hard for a long time for people to understand why Xanadu is so bright. You might not expect these kinds of geometries in a natural setting, but we believe this can explain the enigma,” adds JPL Cassini radar team member Steve Wall.

The team believes that the lower Xanadu region represents the perfect setting for these icy formations to deposit themselves. It has a very gentle slope, which means that the ice blocks may have traveled for hundred of miles before finally grinding to a halt. The team hypothesizes that their roundness may have been promoted by the friction they had while grinding against sand and small rock on their way. A spherical shape ensures the least friction, they add. Given the long distance the ice traveled, it stands to reason that it had time to adapt before finally settling down.

“Here is yet another example of Titan as a world with Earth-like processes. As the seasons change on Titan, maybe we'll get a chance to see methane flow through some of the river channels,” concludes JPL Cassini project scientist Linda Spilker.