Ganymede Archives

Illustration of key factors affecting subsurface ocean habitability and possible chemical evolution in icy moons Factors with question marks are still under debate. -- The Innovation via PubMed

Dynamic Controls On Subsurface Water Chemistry And Habitability On Icy Moons

by Keith CowingJune 23, 2026June 23, 2026

Icy moons are natural satellites whose surfaces contain a substantial fraction of frozen materials, most notably water ice.

This artist's impression shows radar waves from the NASA Goldstone Solar System Radar pinging one of Jupiter’s moons, Europa. The radar waves penetrate Europa’s icy surface before bouncing back to be collected by the NSF Green Bank Telescope on Earth. Credit: NSF/AUI/NSF NRAO/P.Vosteen

Callisto, Europa, Ganymede, Habitable Zones, Icy Worlds, Journal articles, Press Release, Water/Hycean Worlds & Oceanography

Radar Echoes From Europa Reveal Secrets Beneath the Ice

by Keith CowingJune 18, 2026June 18, 2026

A team of scientists has used NASA’s Goldstone Solar System Radar and the U.S. National Science Foundation Green Bank Telescope (NSF GBT) to carry out the most extensive radar study […]

Locations (yellow circles) of ROIs that include paterae, potential flows, and cryovolcanic candidate regions (K. Stephan et al. 2021a) on top of the global geological map of Ganymede from G. C. Collins et al. (2013). Mercator projection. -- The Planetary Science Journal

Astrogeology, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Ganymede, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Mapping, Geodesy, Cartography, Bathymetry, Missions & Hardware, Status Report

Potential Cryovolcanic Regions on Ganymede: A Priority Target for JUICE

by Keith CowingJune 7, 2026June 26, 2026

One of the Jupiter Icy Moons Explorer (JUICE) mission goals of the European Space Agency, launched in 2023 April, is the detailed characterization of Ganymede, Jupiter’s largest moon and a […]

Examples of materials with extremely high porosities (ϕ > 80%). a) Heesch & Laves (1933) 94.45% rigid packing structure. b) and c) pictures from Blum & Schr¨apler (2004) experiments of SiO2 agglomerates with 85% porosity. d) Water ice aggregates with 89% porosity observed with a long-distance microscope (Gundlach et al. 2011). Bottom Row: experimental pictures from the Core-Mantle Particle Sedimentation System e) Cryogenically cooled chamber with 15 mm high needles that serve as sample mounts for ice aggregates. f) Micrometer-sized water ice spheres as seen from the scanning electron microscope. g) Fractal ice aggregates as seen from the long distance microscope. Each individual grain has been highlighted in yellow on the right side of the picture. -- astro-ph.EP

Astrochemistry, Astrogeology, Icy Worlds, Imaging & Spectroscopy, Status Report

The Physical Nature of Regolith on Icy Moons

by Keith CowingMay 28, 2026May 28, 2026

Estimating surface properties such as porosity and grain sizes is key for planning lander missions and landing site selection on icy moons.

Astrogeology, Callisto, Ganymede, Icy Worlds, Imaging & Spectroscopy, Jupiter, Press Release

Ganymede Might Still Be Forming Its Metal Core Today

by Keith CowingMay 18, 2026May 18, 2026

Jupiter’s moon Ganymede is the largest moon in the solar system; at over 3,200 miles across, it is larger than the planet Mercury. It is also the only moon with […]

Numerical ocean-induction setup for Ganymede in a deep-ocean scenario with REM = 1.77 . Ganymede's internal structure is depicted, featuring the ice crust, the deep ocean with its simulated zonal flow, the internal ice layer, the silicate mantle, and the metallic core. Yellow tubes visualize the magnetic field lines. The bottom-right panel shows how magnetic field lines are sheared by the zonal (east–west) jet flow in the ocean (blue/red denote westward/eastward jets, respectively), thereby reflecting the secondary magnetic field induced by such dynamics. -- Geophysical Research Letters

Astrogeology, Biogeochemical Cycles & Geobiology, Ganymede, Icy Worlds, Jupiter, Magnetic Fields, Electromagnetism, bioelectricity,, Press Release, Water/Hycean Worlds & Oceanography

Motional Induction in Ganymede’s Ocean

by Keith CowingMay 10, 2026May 11, 2026

We investigate the magnetic signature of oceanic circulation in Ganymede’s subsurface ocean using kinematic induction modeling. Our approach couples zonal jet flows from rotating thermal convection simulations with magnetic field […]

Titan is an abode of NH3. (A) Titan captured by the Cassini Imaging Science Subsystem. The thick atmosphere of Titan is visible by a haze across the surface and a lack of surface details. Saturn’s other moon, Tethys, is observed behind Titan. Image credits: NASA/JPL-Caltech/Space Science Institute. (B) False-colour mosaic of Titan obtained by the Visual and Infrared Mapping Spectrometer of Cassini. Colours correspond to atmospheric (red) and surface features (green and blue). The inset image indicates the possible occurrence of a cryovolcano on the surface. Cryovolcanic slurries of water, NH3, and methanol have been tentatively observed on the surface. Image credit: NASA/JPL/University of Arizona.

Enceladus, Europa, Ganymede, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Jupiter, Saturn, Status Report, Titan

Ammonia As A Parameter Shaping Habitability On Icy Moons

by Keith CowingMay 6, 2026May 6, 2026

The search for life now extends beyond the traditional habitable zone to include the icy moons of Jupiter and Saturn. These moons feature ice-covered surfaces overlying substantial oceans formed primarily […]

O+2 density at Ganymede’s surface, modeled from the chemical equilibrium between ionization and recombination of O2, using the electron-impact ionization rates from Figure 2c. Photoionization is included in the sunlight region, which is shown by the terminator in orange. White numbers show modeled density values in cm−3 . For comparison, the red numbers show electron densities detected by Galileo (G8) and Juno radio occultation observations under the assumption of a uniform ionosphere (Kliore, 1998; Buccino et al., 2022). -- astro-ph.EP

Astrogeology, Atmospheres, Climate, Weather, Ganymede, Icy Worlds, Imaging & Spectroscopy, Jupiter, Space Weather & Heliophysics, Status Report

Constraining Electron-Impact Ionization of O2 Through UV Aurora Observations at Ganymede

by Keith CowingApril 16, 2026April 16, 2026

While photoionization rates of Ganymede‘s O2 dominated atmosphere are well constrained, the contribution of electron-impact ionization is rather uncertain.

Artist’s impression of the simulations conducted in this research. Jupiter (lower left) has a strong magnetic field which creates a cavity in its circumplanetary disk. Saturn (upper right) lacks a strong magnetic field so its circumplanetary disk evolves without a cavity. Credit: Yuri I. Fujii/L-INSIGHT [Kyoto University], Illustrator: Shinichiro Kinoshita

Astrogeology, Callisto, Enceladus, Europa, Ganymede, Gas Giants, Icy Worlds, Io, Jupiter, Magnetic Fields, Electromagnetism, bioelectricity,, Press Release, Rhea, Saturn, Titan, Water/Hycean Worlds & Oceanography

How Jupiter Cultivated More Large Moons Than Saturn

by Keith CowingApril 8, 2026April 8, 2026

The two largest planets in our Solar System, Jupiter and Saturn, also have the largest satellite systems, or the most moons. At present, Jupiter’s reported moon count stands at more […]