Radio Signals Could Indicate Vast Ocean on Titan

More than two years after the landing of ESA's Huygens probe on Saturn's largest moon, Titan, scientists are still unable to determine the cause of a strange radio signal detected by the probe. The signal could indicate the presence of a warm underground ocean.

These low frequency emissions are similar to emissions found on Earth, when lightning creates radio waves that bounce between the surface and the upper atmosphere.  Titan’s water ice surface should not reflect these waves very well. However, a liquid ocean tens of kilometres under the ice could cause reflections.

The Huygens probe landed on Titan on 14 January 2005, and beamed back data for almost four hours. Scientists reported early results from the probe in December 2005, and are now announcing further findings in the journal Planetary and Space Science.

Huygens landed on a plain of ice with organic coatings that form when solar radiation reacts with methane at high altitudes. This process causes hydrocarbons, such as acetylene and ethane, to build up, while more complex nitrogen-bearing molecules drift down to the surface.

Images from the probe also show deep, branching channels in hills north of the landing site, and a new model of the wind pattern suggest the atmosphere acts like a giant conveyor belt, with gas circulating from the south pole to the north then back to the south pole. According to Laurence Soderblom from the US Geological Survey in Arizona, “Titan’s river channels, canyons and flood plains rival the variety on Earth.”