The oceans of several moons orbiting Jupiter and Saturn are considered among the most promising environments for finding extraterrestrial life. Buried beneath kilometres of ice, the moons’ surfaces may carry crucial information about the oceans below. Dr. Stéphanie Cazaux has received an ERC Advanced Grant to study the interaction between the moons’ oceans and their icy surface to identify potential access pathways to these oceans and assess what surface observations can reveal about the oceans’ composition and physical conditions.
In our solar system, several moons orbiting Jupiter and Saturn host vast oceans buried beneath kilometres of ice. These hidden oceans, considered amongst the most promising environments to host extraterrestrial life, are now a priority in both ESA and NASA’s programs for future missions. “Better understanding these oceans and how their material reaches the surface is key to exploring them indirectly, helping us make the most of future space exploration and identify possible pathways to visit them in the future.” says Cazaux, planetary researcher at the Faculty of Aerospace Engineering at the TU Delft.
From ocean depths to surface clues
No easy task, as direct access to these oceans is currently not possible. Luckily, their presence can be inferred indirectly. On Enceladus, ocean water escapes through geysers; on Europa, subsurface fluids spill onto the surface; and in other cases, ocean molecules slowly diffuse through the ice, eventually freezing on the surface. As a result, surface ice may carry crucial information about the ocean beneath.
Light-based fingerprints
The processes by which ocean material becomes surface ice will be studied both experimentally and theoretically. This will help determine the physical and chemical characteristics of ice, as well as its spectral signatures. The latter is relevant as recent observations by the James Webb Space Telescope (JWST) have revealed subtle variations in light reflected from the surfaces of Ganymede and Europa. These so-called spectral signatures, basically light-based “fingerprints”, are difficult to interpret but likely linked to how surface ice forms and evolves.
Source: News article TU Delft.