In the outer solar system beyond Jupiter, water ice is a dominant component of planetary bodies, and most solid objects in this region are classified as icy bodies.
Posted inAriel, Astrogeology, Callisto, Ceres, Charon, Dione, Enceladus, Europa, Ganymede, Iapetus, Ice Giant, Icy Worlds, Mapping, Geodesy, Cartography, Bathymetry, Mars, Mimas, Miranda, Missions & Hardware, Moon, Oberon, Phoebe, Pluto, Polar / Alpine Expeditions, Rhea, Status Report, Tethys, Titan, Titania, Triton, Umbriel, Water/Hycean Worlds & Oceanography
![The region in which dark matter impacts may leave detectable surface features on Ganymede. Gray regions correspond to existing constraints [33, 35, 37]. The light purple region is the region in which the dark matter has sufficient initial energy to penetrate through the 12 km conductive ice layer on Ganymede’s surface. The darker purple region corresponds to when the dark matter penetrates the entirety of Ganymede, leaving both an entrance and exit wound. Rough estimates for the approximate number of craters and crater radius from Eqs. 1 and 13 are provided on the top and right axes respectively, rounded to one significant figure for readability. -- astro-ph.EP](https://i0.wp.com/astrobiology.com/wp-content/uploads/2025/08/Dark-Wounds-On-Icy-Moons.png?resize=1200%2C720&ssl=1)
![A: Schematic of the ultra-high vacuum chamber used for electron irradiation experiments of Europan ice analogs. B: Shift in the resonant frequency of the QCM during co-deposition of H2O and CO2 ice from dedicated gas dosers. We first condense CO2 [1] from a doser at a constant rate of (0.25 ± 0.01) Hz/s (zoomed in the inset). We then admit water vapor [2] through a second doser which increases the deposition rate to (4.8 ± 0.2) Hz/s. When the film approaches the desired thickness (2.8 µm, which corresponds to a frequency shift of ∼ 21, 000 Hz), we terminate H2O gas deposition first [3] and continue with CO2 condensation briefly to ensure the terminal CO2 rate did not drift significantly from the initial value (< 10%). The CO2 doser is shut off at [4]. This co-deposition scheme using multiple gas dosers with QCM gravimetry allows for producing mixed ices with precisely tailored composition. This film has CO2 intimately mixed with water ice at (2.5 ± 0.1)% (by number) concentration. -- astro-ph.EP](https://i0.wp.com/astrobiology.com/wp-content/uploads/2025/06/Laboratory-Investigation-Of-CO2-Driven.png?resize=1200%2C733&ssl=1)
