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Gabriel Tobie
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Porous Media as a Means to Promote Exchange Processes in Icy Worlds of the Outer Solar System
Beyond the orbit of Mars, most of the solid planetary bodies contain a large fraction of water ice. During the last three decades, a series of space missions to Jupiter’s system (Galileo 1995-2003, Juno (2016-2026), Saturn’s system (2004-2017), dwarf planets Ceres (Dawn (2014-2018) and Pluto (New Horizons 2015), have revealed that several of these icy worlds possess salty water oceans beneath their icy crust. Due to lower gravity and reduced hydrostatic pressure and temperature compared to the terrestrial context, porosity can be maintained over geological timescales and sustained active exchange processes between the different layers constituting their interior. Porous media processes therefore play a key role in promoting chemical and thermal transport in these extraterrestrial environments, including hydrothermal water flow in their porous rocky core, tidally-induced porous flow at the ocean interface and in partially melted layers, and vapor transport through the porous ice near the surface and in active faults. In this presentation, I will review the current knowledge about these icy worlds and highlight a series of active processes revealed by recent exploration, involving porous media.
Interview with Gabriel Tobie
- What can porous media on moons like Enceladus and Europa teach us about habitability?
Porous media can promote heat and chemical exchanges at the interface between the rocky interior and subsurface ocean on Enceladus and Europa, providing essential energy and nutriments that support the habitability of these oceanic environments.
- What methods are used to study porosity in extraterrestrial environments?
Various methods, including remote-sensing techniques to constrain near-surface porosity, numerical modeling of porous flow and poroviscoelastic deformation, mechanical tests on planetary analogous porous samples, in variaus planetary settings representatvie of surface and interior conditions, are used.
- How do you see planetary and Earth scientists learning from each other?
Planetary scientists can benefit from the long experience of Earth scientists in studying detailed processes under various porous media conditions, while in return, planetary scientists can provide Earth scientists with new insights by exploring processes under more exotic conditions, for example, at lower temperature and gravity, with different planetary materials.
- What excites you most about presenting your research to a broader scientific community?
Sharing the latest results and ideas on planetary exploration, especially on icy moons where porous media processes play a key role in their evolution and present activity.
- What interdisciplinary bridges are you hoping to build at InterPore?
I hope to exchange ideas, encourage potential new studies on porous media in extraterrestrial environments, and possibly initiate collaborations.
About Gabriel Tobie
Gabriel Tobie is Planetary Scientist at CNRS, affiliated to Laboratoire de Planétologie et Géosciences (UMR-6112), Nantes Université, France. His main expertise concerns the study of Jupiter's and Saturn's icy moons. He has been involved in the data analysis and interpretation of the Cassini-Huygens mission (2004-2017), particularly for the study of
Titan and Enceladus, and now actively participates in the preparation of the next space missions to
Jupiter's moons (Europa, Ganymede and Callisto) as co-investigator on both ESA JUICE and NASA Europa
Clipper missions. He coordinated several research projects (ERC, ANR) combining both theoretical modelling and experimental investigations to characterize chemical exchanges and porous processes in icy worlds. Throughout his career, he has trained and mentored 12 PhD students and 8 post-docs, co-authored about 120 research papers.
