Icy Worlds Archives

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 […]

Initial structure of the Impact Plume 60 s post impact. The impactor strikes from the left, at a 60° angle from horizontal, with the sun located to the right.There is a visible asymmetry in the plume due to the direction of impact; the “hole” on the right side of the plume is a bubble in this 2D slice of a fully 3D plume due to the removal of water vapor-rock mixtures from the simulation during the sampling from SOVA into DSMC codes (Prem et al. 2015). (Top) the plume contains a region of high density (~1022 molecules/m3 ) just above the point of impact, which rapidly drops toward the edges of the plume. (Bottom, left) The high plume densities correspond to short mean free paths for the vapor molecules. (Bottom, right) Comparing this mean free path with the length scale of the density gradient reveals very small Knudsen numbers throughout; the entire plume (except for the very outermost edges) is clearly within the continuum flow regime at this time, rather than the slip-flow, Knudsen, or Free Molecular regimes. -- astro-ph.EP

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Comets and Asteroids, Cryobiology, Icy Worlds, Imaging & Spectroscopy, Impact events, Mapping, Geodesy, Cartography, Bathymetry, Mercury, Status Report

Transport of Water In A Transient, Impact-Generated Atmosphere On Mercury

by Keith CowingJune 5, 2026June 26, 2026

Mercury’s polar cold traps host water ice deposits that are likely populated with impact-delivered water via Mercury’s exosphere.

Synthetic Aperture Radar (SAR) images of Ligeia Mare and Ontario Lacus obtained by the Cassini Spacecraft (NASA/JPL-Caltech/ASU/Cornell) and corresponding lake bathymetry. (a) Ontario Lacus: SAR image collected on 12 Jan. 2010 centered at 72°S 183°W. Image ID: PIA13172. Red circled region indicates potential smooth wave-modified coast (Palermo et al., 2024; Wall et al., 2010); (b) Ligeia Mare: a mosaic of SAR images collected between February 2006 and April 2007 and combined to create image PIA17031 centered at 79°N 248°W. Locations of a potential straight wave-modified coast (Wall et al., 2010) and the location of the magic island observations (Hofgartner et al., 2014, 2016) are annotated; SAR-based bathymetric maps of (c) Ontario Lacus and (d) Ligeia Mare (Hayes, 2016) were used as inputs to our wave model. -- Journal of Geophysical Research: Planets

Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Cryobiology, Exoplanets, -moons, -comets, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Status Report, Titan, Water/Hycean Worlds & Oceanography

Modeling the Seasonality of Wind-Driven Hydrocarbon Waves in Titan’s Polar Lakes

by Keith CowingJune 5, 2026June 5, 2026

Titan, the only body in the solar system aside from Earth with standing liquids on its surface, has high-latitude hydrocarbon lakes and seas. As Titan’s atmosphere generates light winds, there […]

(Left) TPD curves of SO2 deposited at 80 K on c-ASW (circles) for different coverages (1 ML, blue; 0.72 ML, red; 0.48 ML, green; 0.16 ML, magenta; and 0.07 ML, orange) in the submonolayer regime, with corresponding first-order fits (black lines). (Right) Associated adsorption energy distribution for each TPD curve. -- astro-ph.GA

Astrochemistry, Astrogeology, Biosignatures & Paleobiology, Callisto, Enceladus, Europa, Ganymede, Icy Worlds, Imaging & Spectroscopy, Status Report

Temperature-programmed Desorption Of SO2 From Water Ice Surfaces: Adsorption Energy Distributions

by Keith CowingJune 5, 2026June 5, 2026

Context. Sulphur-bearing species play a key role in the chemical evolution of the interstellar medium and icy Solar System bodies such as the Jovian moons, yet the sulphur budget remains […]

Mars vast clay region - View showing the transition between clay units in the Oxia Planum and Mawrth Vallis regions on Mars, taken by the HiRISE camera on NASA’s Mars Reconnaissance Orbiter. -- ESA Larger image

Analog Studies, Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Cryobiology, Desert Worlds, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Mapping, Geodesy, Cartography, Bathymetry, Mars, Missions & Hardware, Origin & Evolution of Life, Press Release, Robotics/Rovers/UAVs, Terraforming & Geoengineering, Water/Hycean Worlds & Oceanography

ExoMars Rosalind Franklin Astrobiology Rover Targets A Vast Bed Of Clay In Its Search For Life

by Keith CowingJune 4, 2026June 26, 2026

In the region where the ExoMars Rosalind Franklin rover will search for signs of life, clay deposits extend beyond previous estimates, a new study finds. One hypothesis even suggests a […]

Previous vs. current microbe-integrated ocean world model setups. Previous models (left) include ambient temperatures, hydroxide effluent, circumneutral pH's, and effluent-bacteria integration (Barge et al., 2015; Hermis et al., 2021; Dickson et al., 2022). This study (right) includes thermal gradients, FeOOH/sulfide rich effluent (brine fluid), acidic reservoir pH, and planktonic lake extremophile integration. -- FRONTIERS,

AI - Data - Apps - Cybernetics, Astrogeology, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biophysics, Biosignatures & Paleobiology, Cryobiology, Europa, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Status Report

Probing The Habitability Of Potential Sulfuric Acid Rich Subsurface Lakes In Europa’s Ice Shell Via Saci/STIV Integrated Models

by Keith CowingJune 2, 2026June 2, 2026

Experimentally modeling the habitability of extreme ocean world conditions, such as those on Jupiter’s moon: Europa, would benefit from integrated microbe-virus model studies to provide both a microbial model and […]

Top: coma maps of H2O, CO2, and CH4, computed as the molecular column density from a pixel-by-pixel retrieval analysis for Observations 6, 15, and 6, respectively. The sunward and target velocity directions are denoted by the white arrows. The target centroids, computed as the photocenter in the median-stacked images (Figure 1), are marked with the black points. For H2O and CO2, the white contours correspond to emission levels of 50% and 20% relative to the maximum value and illustrate the slight antisunward extension of the respective comae. The contours are omitted in the CH4 panel, due to the poorer signal-to-noise ratio of the data. Bottom: corresponding median-stacked images across the continuum wavelengths within each fluorescence region. The H2O coma map shows a significant enhancement in the emission level at large nucleocentric distances relative to the dust continuum, indicating extended H2O production within the coma. -- The Astrophysical Journal Letters

Astrochemistry, Astronomy & Telescopes, Biogeochemical Cycles & Geobiology, Biophysics, Biosignatures & Paleobiology, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Interstellar, Press Release

Webb Detects Methane on Interstellar Comet 3I/ATLAS

by Keith CowingJune 2, 2026June 2, 2026

NASA’s James Webb Space Telescope has collected its first mid-infrared chemical fingerprint of an interstellar object during a recent revisit to comet 3I/ATLAS. The team’s results published recently in The […]

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.

Schematic overview of the interior model of Trappist1f,g,h. The ice I layer is divided into a conductive and a convective sublayer. The thermal model determines the thickness of the conductive and convective layers, Rice,I , RHPI, and Qeq. The tidal model computes the tidal heating rates in the HPI, and the mantle. The layer boundaries are not to scale. Note that the convective layer -- astro-ph.EP

Astrogeology, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Icy Worlds, Imaging & Spectroscopy, Press Release, TRAPPIST-1, Water/Hycean Worlds & Oceanography

Interior-Atmosphere Coupling on TRAPPIST-1 f, g, and h: Cryovolcanic Water Exospheres and Infrared Detectability

by Keith CowingMay 28, 2026May 28, 2026

We investigate the interior structures and cryovolcanic observability of the exoplanets TRAPPIST-1f, g, and h. Our aim is to determine which interior configurations can sustain subsurface liquid water oceans in […]