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Jupiter's icy moon Europa is currently seen as the most habitable world closest to Earth. Data from the space mission Galileo supported the presence of a global subsurface water ocean in direct contact with a rocky mantle, implying possible rock-water processes similar to those occurring on Earth's ocean floor, which is teeming with life. Although Juno can provide occasional glimpses of the Galilean satellites, close-up observations are not expected until the arrival of Europa Clipper and JUICE in the Jovian system. In the meantime, radar astronomy can help expand our understanding of this intriguing ocean world.There are ongoing efforts to determine Europa's obliquity from radar echoes observed with the Goldstone Solar System Radar and the Green Bank Telescope [1]. In this contribution, we will present our latest models for icy moon obliquity and nutations, and demonstrate the need for precise modelling of elastic deformation in the ice shell. We will also investigate possible resonant amplification of the obliquity due to ocean dynamics.This work is financially supported by the Belgian Science Policy Office (BELSPO) through the BRAIN.be-2.0 programme.[1] Margot J.-L., Spin states of Europa and Ganymede, European Geosciences Union General Assembly 2025
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Double ridge formation over shallow water sills on Jupiter’s moon Europa
Abstract Jupiter’s moon Europa is a prime candidate for extraterrestrial habitability in our solar system. The surface landforms of its ice shell express the subsurface structure, dynamics, and exchange governing this potential. Double ridges are the most common surface feature on Europa and occur across every sector of the moon, but their formation is poorly understood, with current hypotheses providing competing and incomplete mechanisms for the development of their distinct morphology. Here we present the discovery and analysis of a double ridge in Northwest Greenland with the same gravity-scaled geometry as those found on Europa. Using surface elevation and radar sounding data, we show that this double ridge was formed by successive refreezing, pressurization, and fracture of a shallow water sill within the ice sheet. If the same process is responsible for Europa’s double ridges, our results suggest that shallow liquid water is spatially and temporally ubiquitous across Europa’s ice shell.
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- Award ID(s):
- 1745137
- PAR ID:
- 10379947
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Nature Communications
- Volume:
- 13
- Issue:
- 1
- ISSN:
- 2041-1723
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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