Free Astronomy Magazine January-February 2021

37 JANUARY-FEBRUARY 2021 ASTRO PUBLISHING like Titan, it is vital to look for path- ways for organic material, for exam- ple mixtures that contain important elements, like carbon,” says Anez- ina. “These can be recognizable at the surface and in the atmosphere after being transported from the subsurface ocean, which is the most likely habitable environment, and vice versa. Impact craters are one of the few geologic features that ex- pose material from the interior, pro- viding a rare opportunity to under- stand the subsurface composition of Titan.” Six of the craters in the study are lo- cated in the equatorial dune fields and three in the midlatitude plains. They used data from two instru- ments on the Cassini orbiter; the Visual and Infrared Mapping Spec- trometer (VIMS) and RADAR, along with information provided by the Huygens Titan lander. RADAR obtained microwave emis- sivity data – which is a measure of how effective a surface is at emit- ting energy – and could probe the surface to depths of tens of centime- tres revealing details on the subsur- face composition. Areas with lower emissivity on Titan are thought to indicate water ice, I n the background, a graphic representa- tion of Titan’s hazy atmosphere, which prevents a clear view of the surface. In the side, we relive the salient phases of ESA’s Cassini-Huy- gens mission, which unveiled the surface of Titan for the first time. [ESA, NASA/JPL]