Callisto Archives

Major icy bodies in the Solar System, with the Earth’s moon to scale. The images are shown at the proper relative size. From NASA’s Planetary Photojournal (https://photojournal.jpl.nasa.gov/), Earth’s Moon (PIA00302), Europa (PIA00502), Ganymede (PIA00716), Callisto (PIA03456), Mimas (PIA06258), Enceladus (PIA06254), Tethys (PIA07738), Dione (PIA08256), Rhea (PIA08256), Titan (PIA08256), Hyperion (PIA07740), Iapetus (PIA08384), Phoebe (PIA06064), Miranda (PIA18185), Ariel (PIA01534), Umbriel (PIA00040), Titania (PIA01979), Oberon (PIA00034), Triton (PIA00317), Pluto (PIA19952). -- astro-ph.EP

Ariel, 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

Icy Worlds: Moons And Dwarf Planets

by Keith CowingDecember 1, 2025December 1, 2025

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.

An artistic rendering of a dust and gas disk encircling the young exoplanet, CT Cha b, 625 light-years from Earth. Spectroscopic data from NASA’s James Webb Space Telescope suggests the disk contains the raw materials for moon formation: diacetylene, hydrogen cyanide, propyne, acetylene, ethane, carbon dioxide, and benzene. The planet appears at lower right, while its host star and surrounding circumstellar disk are visible in the background. Illustration: NASA, ESA, CSA, STScI, Gabriele Cugno (University of Zürich, NCCR PlanetS), Sierra Grant (Carnegie Institution for Science), Joseph Olmsted (STScI), Leah Hustak (STScI)

Astrochemistry, Astrogeology, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Callisto, Exoplanets, -moons, -comets, Ganymede, Icy Worlds, Imaging & Spectroscopy, Press Release

Webb Studies A Carbon-rich Moon-Forming Disk Around A Massive Planet

by Keith CowingSeptember 30, 2025September 30, 2025

NASA’s James Webb Space Telescope has provided the first direct measurements of the chemical and physical properties of a potential moon-forming disk encircling a large exoplanet. The carbon-rich disk surrounding […]

Maps showing Callisto’s bolometric albedo (a; from Camarca et al. 2023) compared with the spectral slope from 360 to 410 nm (b), which measures the strength of the near-UV downturn (redder slope = stronger downturn). -- astro-ph.EP

Astrochemistry, Astrogeology, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Callisto, Icy Worlds, Imaging & Spectroscopy, Status Report

Spectroscopic Mapping of Callisto with HST/STIS and Implications for its Surface Composition

by Keith CowingJune 3, 2025June 3, 2025

We present global, spatially resolved ultraviolet-visible spectra of Callisto obtained with HST/STIS and explore possible compositions of Callisto’s surface material.

Astrogeology, Biogeochemical Cycles & Geobiology, Callisto, Ganymede, Icy Worlds, Mapping, Geodesy, Cartography, Bathymetry, Press Release

Conditions For Accretion Favoring An Unmelted Callisto And A Differentiated Ganymede

by Keith CowingMay 13, 2025May 13, 2025

Analysis of Callisto’s moments of inertia, derived from Galileo’s gravity data, suggests that its structure is not fully differentiated.

Image of Antarctica as seen by human eyes from orbit - Fram2/SpaceX

Analog Studies, Arctic / Antarctic / Alpine, Astrogeology, Atmospheres, Climate, Weather, Away Teams & Field Reports, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Callisto, Cryobiology, Enceladus, Europa, Extremeophiles and Extreme Environments, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Jupiter, Mapping, Geodesy, Cartography, Bathymetry, Missions & Hardware, Nomenclature, Systematics, Natural History, Robotics/Rovers/UAVs, Water/Hycean Worlds & Oceanography

Ice Planet Exploration: A Dataset Of Antarctic Ecosystems In Ice-free Lands

by Keith CowingMay 8, 2025May 8, 2025

Astrobiology.com Editor’s note: Recently the Fram2 mission took four astronaut explorers on an orbital path that covered both of our planet’s polar regions. This was the fist human mission to […]

Callisto’s crater-covered surface may be hiding a liquid water ocean. Credit: NASA/JPL-Caltech/Kevin M. Gill, CC BY 2.0 Source: AGU Advances

Astrogeology, Biosignatures & Paleobiology, Callisto, Icy Worlds, Jupiter, Press Release, Water/Hycean Worlds & Oceanography

Callisto Is Very Likely an Ocean World

by Keith CowingFebruary 21, 2025February 21, 2025

More pocked with craters than any other object in our solar system, Jupiter’s outermost and second-biggest Galilean moon, Callisto, appears geologically unremarkable. In the 1990s, however, NASA’s Galileo spacecraft captured […]

Block diagram of the proposed multi-physics simulation model LunaIcy. -- astro-ph.EP

Astrogeology, Biogeochemical Cycles & Geobiology, Callisto, Cryobiology, Europa, Ganymede, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Mapping, Geodesy, Cartography, Bathymetry, Status Report, Water/Hycean Worlds & Oceanography

LunaIcy: Exploring Europa’s Icy Surface Microstructure through Multiphysics Simulations

by Keith CowingOctober 22, 2024October 22, 2024

A multiphysics simulation model incorporating a sintering model coupled with the MultIHeaTS thermal solver was developed to study the evolution of icy moons’ microstructure.

JUICE-Europa Clipper Tage Team exploration of Jovian Space -- ESA

Callisto, Europa, Ganymede, Habitable Zones, Icy Worlds, Jupiter, Water/Hycean Worlds & Oceanography

Astrobiology.com on Deutsche Welle: Europa Clipper and ESA Juice

by Keith CowingOctober 14, 2024October 15, 2024

Editor’s note: I was just on Deutsche Welle talking about the Europa Clipper mission – as well as ESA’s Juice mission – and how they will work in tandem exploring […]

The UVS instrument recorded spatial information produced by hydrogen atoms radiating from the Earth. In the background a number of individual stars are identified along with the Pleiades star cluster. Juice-UVS plans to similarly observe hydrogen atoms radiating from Ganymede and Jupiter’s other icy moons. Credit Southwest Research Institute

Callisto, Europa, Ganymede, Icy Worlds, Jupiter, Missions & Hardware, Press Release

Astrobiology Fleet Update: ESA Juice Tests SwRI Ultraviolet Spectrograph

by Keith CowingOctober 9, 2024October 9, 2024

As European Space Agency (ESA)’s Jupiter Icy Moons Explorer (Juice) spacecraft hurtled past the Moon and Earth in mid-August to provide its first gravity assist maneuver to the Jovian system, […]

Above: Examples of typical surfaces of the icy Galilean satellites (panel a: Europa, near Conamara Chaos region at 8.1°N/90.9°E; panel b: Ganymede, Nicholson Regio at ∼14°S/12.7°E; panel c: Callisto, detail of Asgard impact basin at 14.7°N/218°E). All images are scaled to 150 m px−1. The crater density (a proxy of surface age) increases from Europa to Callisto, reflecting the geological history of surface processes. The surface of Europa displays the most complex inventory of landforms that were formed by endogenic processes, whereas Callisto’s surface is almost devoid of any evidence for tectonic and cryovolcanic activity (Image: NASA/DLR). Below: Models of the interiors of the icy Galilean satellites (Images: ESA/ATG Medialab). Details on their examination by JUICE are provided by Van Hoolst et al. (2024, this collection) -- pace Sci Rev via PubMed

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Callisto, Europa, Ganymede, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Jupiter, Mapping, Geodesy, Cartography, Bathymetry, Missions & Hardware, Status Report

Characterization of the Surfaces and Near-Surface Atmospheres of Ganymede, Europa and Callisto by JUICE

by Keith CowingSeptember 17, 2024September 17, 2024

We present the state of the art on the study of surfaces and tenuous atmospheres of the icy Galilean satellites Ganymede, Europa and Callisto, from past and ongoing space exploration […]

Callisto

Icy Worlds: Moons And Dwarf Planets

Webb Studies A Carbon-rich Moon-Forming Disk Around A Massive Planet

Spectroscopic Mapping of Callisto with HST/STIS and Implications for its Surface Composition

Conditions For Accretion Favoring An Unmelted Callisto And A Differentiated Ganymede

Ice Planet Exploration: A Dataset Of Antarctic Ecosystems In Ice-free Lands

Callisto Is Very Likely an Ocean World

LunaIcy: Exploring Europa’s Icy Surface Microstructure through Multiphysics Simulations

Astrobiology.com on Deutsche Welle: Europa Clipper and ESA Juice

Astrobiology Fleet Update: ESA Juice Tests SwRI Ultraviolet Spectrograph

Characterization of the Surfaces and Near-Surface Atmospheres of Ganymede, Europa and Callisto by JUICE

PJ Harvey Announces New Song “Voyager”

Fifty Years after Viking: The Promise of Solar System Microbiology and Microbial Ecology

Characterising Transiting Exoplanets At Long Orbital Period: Lessons Learned For PLATO From 10 Years Of Monitoring The HIP41378 System

Implications Of Self-consistent H2O Ice Optical Constants On Radiative Transfer Models Of Disks

The GAPS Programme at TNG LXXIV. A Reanalysis Of The Planetary Systems TOI-1272 And TOI-1694 With HARPS-N And Retraction Of The Planetary Interpretation Of TOI-1272 c