Icy Worlds Archives

Coordinate systems. (a) Schematic of the coordinate systems. e𝜃 and er are the meridional (latitudinal) direction and the vertical direction (opposite to the gravitational direction), respectively. ez and es are the axial direction aligned with planetary rotation and the radial direction perpendicular to it, respectively. e𝜙 represents both the zonal direction in spherical coordinates and the azimuthal direction in cylindrical coordinates. (b) Distribution of 𝐻𝑧 in the simulation with Enceladus-like parameters: a core radius of 192 km and an ocean surface radius of 232 km. Outside the tangent cylinder, 𝐻𝑧 is kept constant. In (a) and (b), gray dashed lines indicate the tangent cylinder. -- astro-ph.EP

Astrogeology, Exoplanets, -moons, -comets, Icy Worlds, Water/Hycean Worlds & Oceanography

Parameterizing Slantwise Convection In Icy Moon Oceans

by Keith CowingJune 25, 2026June 25, 2026

Convection in icy moon oceans is strongly influenced by rotation, organizing into slantwise columnar structures aligned with the planetary rotation axis. They generate significant meridional heat transport, which can affect […]

Surface electrostatic maps of adenylate kinase (Adk), β-galactosidase (β-Gal), DNA ligase (LigA), glycerol kinase (GlpK), histidinol-phosphate aminotransferase (HisC), malate dehydrogenase (MDH) and signal recognition particle 54 (SRP54) are shown for Escherichia coli (mesophile), Psychromonas ingrahamii (psychrophile), Haloferax volcanii (halophile), and Halorubrum lacusprofundi (psychrohalophile). Electrostatic potentials were calculated from predicted structures and mapped onto the molecular surface. Blue indicates positive electrostatic potential and red indicates negative electrostatic potential. -- Frontiers in Microbiology

Cryobiology

Coordinated Proteome-scale Remodeling Underlies Polyextremophilic Survival In Antarctic Cryo-hypersaline Brines

by Keith CowingJune 24, 2026June 24, 2026

Introduction – Cryo-hypersaline brines combine sub-zero temperatures with near-saturated salinity, creating one of Earth’s most extreme habitats. Antarctic Deep Lake provides a natural model for studying how proteins remain stable […]

Interstellar Comet 3I/ATLAS (NIRSpec IFU) -- ESA (larger Image)

Comets and Asteroids

Webb Finds Clues To The Ancient Origin Of Comet 3I/ATLAS

by Keith CowingJune 23, 2026June 23, 2026

The third identified interstellar comet in human history has a surprising chemical makeup, raising questions as to how common, or unusual, conditions in our own Solar System may be.

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

Icy Worlds

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.

Boundary conditions of CO₂ and grey opacity values for tree growth on Mars. Below the green zone conditions are too cold for tree growth. Within the green zone the darker the green color, the greater the proportion of Mars’ surface that allows plant growth (the darkest green corresponds to ~75% of the surface being suitable for tree growth. Above the dark green zone increase in CO2 or greenhouse opacity reduce the fraction of the planet suitable for tree growth as a result of high temperatures. The red lines indicate what percentage of the surface is too hot to allow plant growth. https://doi.org/10.1371/journal.pone.0349588.g005 -- PLOS

Terraforming & Geoengineering

Conceptual Thermal Constraints On The Growth Of The First Tree On A Terraformed Mars

by Keith CowingJune 23, 2026June 26, 2026

The environmental conditions on present‑day Mars are far outside the range tolerated by known complex terrestrial life.

South polar stereographic projection of the Enceladus flybys for the Case 1 trajectory obtained in full fidelity and with all constraints. Numbered markers indicate each flyby and are placed at the point of closest approach, while the altitude evolution through the flyby hyperbola is mapped with a colorbar. -- Acta Astronautica

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Cryobiology, Habitable Zones, Icy Worlds, Missions & Hardware, Sample Return, Status Report, Titan, Water/Hycean Worlds & Oceanography

Trajectory Design For A Titan-Enceladus Plume Sampling Pseudo-orbiter Mission

by Keith CowingJune 21, 2026June 21, 2026

The exploration of the Saturnian system, and in particular the plumes and subsurface ocean of Enceladus, has been identified as a key science theme for ESA’s Voyage 2050 program.

Panels (a)–(o) show contour maps of the observed isophotes (black lines) together with the corresponding modelled isophotes (red lines) for the case 𝑟max = 1 cm. For each of these contour panels, a companion plot is displayed to the right, labelled (a′ )–(o′ ), showing a one-dimensional scan extracted along the direction indicated by the straight red line in the corresponding contour map. In these primed panels, the black and red curves represent the observed and modeled brightness profiles, respectively. The 𝑥- and 𝑦-axes in the contour plots are given in pixel units, and the innermost isophote levels as well as the physical dimensions of each image are listed in Tables 1 and 3. In panels (a)–(o), isophote levels increase outward in steps of 1 mag. In the primed panels, the 𝑥-axis is expressed in pixel units and the 𝑦-axis in surface brightness units (mag arcsec−2). -- astro-ph.EP

Astrochemistry, Astrogeology, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Interstellar, Status Report

Dust Colour, Phase Behaviour, And Monte Carlo Modelling Of Interstellar Comet 3I/ATLAS From 4 au Pre- to 4 au Post-Perihelion

by Keith CowingJune 19, 2026June 19, 2026

We report multi-band photometric imaging observations and Monte Carlo dust tail modelling of the interstellar comet 3I/ATLAS covering a wide range of heliocentric distances, from about 4 au pre-perihelion to […]

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 […]

ID: ESP_087131_2640 date: 26 February 2025 altitude: 316 km larger image

Astrogeology, Biogeochemical Cycles & Geobiology, Desert Worlds, Icy Worlds, Imaging & Spectroscopy, Mars, Status Report

The Spring Awakening of Martian Polar Dunes

by Keith CowingJune 16, 2026June 16, 2026

During the Martian winter, carbon dioxide ice (dry ice) blankets various landforms, including dunes, in the northern high latitudes. As spring arrives, the ice sublimates, causing unique changes on the […]

An artist’s rendition of Saturn’s moon Enceladus depicts hydrothermal activity on the seafloor and cracks in the moon’s icy crust that allow material from the watery interior to be ejected into space. New research shows that instruments destined for the next missions could find traces of a single cell in a single ice grain contained in a plume. NASA/JPL-Caltech

Astrochemistry, Astrogeology, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Enceladus, Habitable Zones, Icy Worlds, Status Report

Tidal Rock Grinding As A Source Of H2 On Enceladus

by Keith CowingJune 16, 2026June 16, 2026

The Solar System hosts multiple potentially habitable environments, including the subsurface ocean beneath the icy crust of Saturn’s moon Enceladus.

Icy Worlds

Parameterizing Slantwise Convection In Icy Moon Oceans

Coordinated Proteome-scale Remodeling Underlies Polyextremophilic Survival In Antarctic Cryo-hypersaline Brines

Webb Finds Clues To The Ancient Origin Of Comet 3I/ATLAS

Dynamic Controls On Subsurface Water Chemistry And Habitability On Icy Moons

Conceptual Thermal Constraints On The Growth Of The First Tree On A Terraformed Mars

Trajectory Design For A Titan-Enceladus Plume Sampling Pseudo-orbiter Mission

Dust Colour, Phase Behaviour, And Monte Carlo Modelling Of Interstellar Comet 3I/ATLAS From 4 au Pre- to 4 au Post-Perihelion

Radar Echoes From Europa Reveal Secrets Beneath the Ice

The Spring Awakening of Martian Polar Dunes

Tidal Rock Grinding As A Source Of H2 On Enceladus

Atmospheric Evolution Through Outgassing And Escape On Young Molten Rocky Exoplanets

The Exozodi Spectral Effect: Residual Habitable Zone Dust May Bias ExoEarth Characterization

The Majority Of Hot Jupiters Formed Beyond The Water Ice Line

Sulfur Photochemistry Observationally Traces Mantle Redox States Of Rocky Planets

Tracing The Source Of Carbon Oxides On The Large Moons Of Uranus