“Titan is fascinating because it has some surprising properties so similar to Earth,” said planetary scientistOded Aharonson from the California Institute of Technology. “It has a liquid which erodes channels, an atmosphere, a hydrologic cycle, and many other parallels.”

Chief among Titan’s interesting qualities is that it's the only body other than Earth where liquids are known to flow in large concentrations on the surface. Because average temperatures there are -300 degrees Fahrenheit, these liquids are not water. Instead, hydrocarbons such as methane and ethane rain down from clouds, course over the landscape in rivers and eventually pour out into large lakes and seas.