The joint NASA-ESA probe Cassini has completed its arc around the north pole of Titan, the largest of Saturn’s many moons and a favored candidate for future human colonization. The data it has sent back shows two vast seas and dozens of small lakes arranged around the pole, but not seas of water like here on earth. The depressions of Titan are filled with liquid heavy hydrocarbons such as methane, ethane and nitrogen. These are the same compounds that comprise the fossil fuels used so voraciously all over the world, and a single sea of Titan contains more than three hundred times the volume of all fossil fuels Earth has ever had.
Ligeia is the smaller of the two seas spotted by Cassini and is estimated to have a volume of about nine thousand cubic kilometers. Kraken, the larger sea is estimated to be four or more times larger than Ligeia. Cassini’s discoveries of the nature and location of the seas and surrounding lakes shed light on the nature of how the bedrock and crust of Titan are structured. Sharp edges seen in radar scans hint at the possibility of tectonic activity under the crust being responsible for the basins the lakes now occupy. Bright deposits along the shores of Ligeia and Kraken are evidence that the surface of Titan is formed of solid hydrocarbons, meaning “rocks and dirt” strewn about the crystallized surface are formed of the basis of ethanol fuel, making Titan an even more enticing opportunity for future space explorers.
The journey that would lead to these discoveries began on October 15, 1997, when the Cassini-Huygens Orbiter launched from Cape Canaveral towards the first of many speed boosting gravity assisted slingshot maneuvers around Jupiter and back past Earth in 1999. After taking a series of photographs to calibrate its systems, Cassini launched towards Saturn, on a mission to determine the origin and nature of the Gas Giant and it’s moons. In 2005, the Huygens probe, built by the European Space Agency, landed on the surface of Titan and began relaying high resolution images and data back to Earth using the Cassine orbiter as a relay directly from the surface. In 2006, radar scans showed evidence of liquid lakes on the surface of Titan, which was confirmed in 2007.
Cassini’s journey has allowed scientists to answer many questions about the Saturn system, but these newest discoveries are opening doors that until now were unconsidered. Having analyzed the composition of Ligeia previously and confirming its depth to be one hundred and seventy meters using its radar module, Cassini will spend the majority of it’s return orbit poring over Kraken, the even larger lake estimated to be roughly the size of the Caspian Sea. Cassini’s orbit brings it back past Titan in August 2014, after which it will be in position to observe the annual ice and gas jet storms of Enceladus, another of Saturn’s dozens of moons. After swinging around Enceladus Cassini will be on a trajectory that takes it into the atmosphere of Saturn. It will transmit data as long as possible before it is expected to be lost in September 2017.
By Daniel O’Brien