JUICE (JUpiter ICy moons Explorer) is the first Large ESA mission in the Cosmic Vision Science program. JUICE was launched in 2023 and is aimed to study the Jupiter system in 2031-2035 where it will answer major science goals of the Jovian atmosphere and the Galilean satellites (Grasset et al., 2013). JANUS (Jovis, Amorum ac Natorum Undique Scrutator) is the high-resolution camera on JUICE and operates in the spectral range 340-1080 nm. The instrument is equipped with 13 filters and a detector of 1,504x2,000 pixels with a pixel FOV of 15 microrad and a total FOV of 1.29ºx1.72º (Palumbo et al. 2025).

JANUS imaged the Earth during and shortly after a Lunar and Earth Gravitational Assist maneuver (LEGA) on 19-20 August 2024. Earth observations offer a real testbed scenario to the science investigation of the Jovian atmosphere (Fletcher et al. 2023). Close approach observations were acquired at spatial resolutions of 126-256 m/pix and covered a narrow strip of the planet in which the spacecraft flew from the night-side over Madagascar, moved over the Indian Ocean, Cambodia and Vietnam and observed the terminator and dawn over Luzon Island. Later observations were acquired over morning to noon hours flying above tropical latitudes over the Western Pacific. Additional observations acquired on September 9, 2024 provided a low-resolution multi-filter portrait of the Earth and the Moon.

The high-resolution images contain atmospheric airglow, convective clouds illuminated by a full Moon, fires in rural areas, lights over the ocean from maritime traffic, city lights over Cambodia and Vietnam, and bright pixels compatible with meteoroids of 1-30 g entering Earth's atmosphere. Images over the terminator and dawn show crepuscular rays under extreme incidence angles with highly convective clouds projecting elongated shadows. Day-time observations show gravity waves on elevated cirrus clouds, sun glint on multi-filter images of the tropical Western Pacific, convective storms over tropical latitudes over the Northwest Pacific and internal waves in the ocean. We compared multi-filter images of the ocean and cloud systems over 12 filters through the JANUS spectral range with spectra obtained by the EnMAP and PRISMA instruments on Earth observing satellites showing good agreement.

These Earth images confirm the expected instrument performance and the ensemble of observations contains a large variety of atmospheric features that are good analogs to multiple systems in Jupiter's atmosphere (Hueso et al. 2026). Additional observations of the Earth will be acquired during the next two Earth flybys on September 2026 and January 2029 providing new data at a wider variety of spatial resolutions.

References

• Fletcher et al. Jupiter Science Enabled by ESA’s Jupiter Icy Moons Explorer, Space Science Reviews (2023).
• Grasset et al. JUpiter ICy moons Explorer (JUICE): An ESA mission to orbit Ganymede and to characterise the Jupiter system, Planet. and Space Sci. (2013).
• Hueso et al., JANUS observations of Earth in preparation for its investigation of Jupiter’s atmosphere, Annales Geophysicae, in preparation (2026).
• Palumbo et al. The JANUS (Jovis Amorum ac Natorum Undique Scrutator) VIS-NIR Multi-Band Imager for the JUICE Mission, Space Science Reviews (2025).

How to cite: Hueso, R., Palumbo, P., Tubiana, C., Portyankina, G., Lara, L. M., Stephan, K., Zinzi, A., Luchetti, A., Agostini, L., Penasa, L., Coustenis, A., Haruyama, J., Kersten, E., Matz, K.-D., Politti, R., Patel, M., Sato, M., Simon, A., Takahashi, Y., and Yair, Y. and the JANUS Earth flyby team: JANUS observations of the Earth during and shortly after JUICE’s Lunar and Earth Gravity Assist (LEGA) on August 2024, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5763, https://doi.org/10.5194/egusphere-egu26-5763, 2026.

Earth is the best-constrained planetary body, yet many Earth-system challenges still require remote-sensing workflows that remain robust under incomplete ground truth, multi-sensor heterogeneity, and complex observation geometries. Planetary science has long operated under these constraints, developing interpretation strategies and processing practices that are increasingly relevant for Earth Observation (EO) applications in hazard monitoring, environmental change, and geological process understanding. In line with the PS1.3 scope of transferring planetary-science methodologies to advance Earth-system knowledge, we present an education-driven framework designed to operationalise this methodological transfer at MSc level.
We describe the structure and rationale of a new Earth Observation curriculum embedded within an MSc in Planetary Sciences, conceived as an “educational pipeline” that trains students to move from sensor-aware analysis to geology-driven interpretation and application-ready products. The curriculum integrates core modules on Earth Observation analysis, satellite multi/hyperspectral data analysis, and geospatial technologies, followed by geology-centred Earth-system applications (e.g., sedimentary environments, marine geology, global changes) and applied EO modules targeting volcanic monitoring and tectonic deformation. A distinctive component is digital field mapping with emerging technologies, designed to explicitly link remote-sensing products to validation strategies and field-based geological reasoning. The training pathway is reinforced through institutional collaboration with national agencies and research bodies, enabling exposure to operational practices and real-world constraints.
We argue that the key innovation lies in implementing a reproducible planetary-to-Earth methodological transfer framework based on: (i) observation-geometry and uncertainty-aware processing, (ii) scalable multi-sensor analytics, (iii) process-based geological interpretation, and (iv) field-connected validation and mapping. By framing education as a mechanism for transferring robust planetary methodologies into EO practice, this approach contributes to bridging planetary and Earth-system sciences while producing graduates capable of translating EO data into reliable, decision-relevant geoscience knowledge.

Keywords: comparative planetology; Earth Observation; remote sensing; hyperspectral; GIS/geoprocessing; hazards; digital field mapping. 

How to cite: Pondrelli, M., Salese, F., Coletta, A., Flamini, E., Mancini, F., Pace, B., Iezzi, G., Satolli, S., Vessia, G., Boncio, P., and Ori, G. G.: Education as a transfer mechanism: translating planetary remote sensing methodologies into operational Earth Observation for Earth-system applications, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20005, https://doi.org/10.5194/egusphere-egu26-20005, 2026.

Venus hosts hundreds of enigmatic circular tectono-magmatic features known as coronae, whose origins, activity state, and role in planetary heat loss remain among the most persistent open questions in Earth and planetary sciences. Coronae display extraordinary diversity in size, morphology, topography, gravity signatures, and tectonic setting, indicating that they do not represent a single formation mechanism, but instead reflect a spectrum of dynamic processes. Understanding these structures is critical not only for deciphering Venus’ geodynamic regime, but also for assessing whether similar processes may have operated on the early Earth before, or during, the onset of sustained plate tectonics.

Here, we present new insights into the coronae enigma by integrating results from a newly compiled global corona database with joint analysis of topography and gravity observations, complemented by recent three-dimensional thermo-chemical geodynamic modeling. The updated database includes 741 coronae, substantially more than previously catalogued features, enabling a more accurate global-scale statistical assessment of coronae morphology, geological setting, and spatial distribution. The expanded dataset reveals numerous corona(-like) structures not previously recognized and highlights systematic variations in corona expression across different tectonic environments.

We investigate the topography and gravity signatures of the largest coronae using Magellan datasets. By analyzing free-air gravity anomalies together with key topographic characteristics, we identify distinct classes of coronae that exhibit signatures consistent with buoyant mantle support and different styles of plume–lithosphere interaction, including scenarios in which crust is recycled back into the mantle through lithospheric delamination or subduction-like processes. Importantly, our analysis further reveals that the limited spatial resolution of the Magellan gravity field can obscure or suppress positive gravity anomalies beneath some coronae, particularly where deep annular troughs surround an uplifted interior. This suggests that a subset of potentially active coronae could be effectively “hidden” in current geophysical datasets. These coronae therefore represent key observables for forthcoming missions such as ESA's EnVision and NASA's VERITAS.

Finally, we explore how corona-formation models are relevant to early Earth evolution.  These results provide a framework for evaluating plume-induced lithospheric weakening and transient subduction-like behavior as key mechanisms for the onset of plate tectonics on our planet.

How to cite: Gülcher, A.: Venus: The Coronae Enigma and Lessons for Earth, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20108, https://doi.org/10.5194/egusphere-egu26-20108, 2026.

We argue that the habitability of terrestrial planets is linked to plate tectonics. We base our proposal on two premises.

First, in the absence of a robust magnetic field, a planet’s atmosphere is vulnerable to stripping by the solar wind, leading to catastrophic water loss and, ultimately, sterilization, as exemplified by modern Mars and Venus.

Second, a strong intrinsic planetary magnetic dipole must be generated by vigorous convection in the liquid core, which in turn requires efficient removal of heat from the core. On Earth, this heat removal occurs through the operation of plate tectonics.

The contrasting evolutionary paths of Earth, Venus, and Mars provide a natural laboratory for examining these relationships. Unlike Earth, both Mars and Venus lack plate tectonics and simultaneously lack a strong magnetic field. Venus currently operates in a stagnant-lid regime, in which heat loss occurs primarily by conduction across a thick lithosphere. This mode of heat transfer appears insufficient to sustain a core dynamo, resulting in the absence of a magnetic field and, consequently, in the loss of water and the development of an uninhabitable environment.

Another key “experiment” is recorded in Earth’s own history at the end of the Ediacaran period. This interval was preceded by approximately 1.5 billion years of a gradual decline in Earth’s dipole moment, from values comparable to the present field to a minimum that was roughly 30 times weaker. This minimum field strength persisted between 591 and 565 Ma, followed by a rapid threefold strengthening by about 532 Ma. Concurrently, atmospheric and oceanic oxygen levels began to rise, supporting an increase in the abundance and size of living organisms. These developments are commonly attributed to the formation of the inner core around ~550 Ma. However, both inner core growth and the associated intensification of the magnetic field would have been impossible without the simultaneous onset of plate tectonics. Thus, it was this tectonic regime change that enabled the rapid expansion of habitability at the Precambrian–Phanerozoic boundary.

We conclude that, although direct evidence remains limited, current scientific understanding strongly supports the notion that Earth’s long-term habitability is linked to the operation of plate tectonics, which sustains the geodynamo and protects the atmosphere from erosion by the solar wind. Nevertheless, the fundamental question of why Earth retained a functioning dynamo through plate tectonics, whereas Mars and Venus did not, remains an open problem for future investigation.

How to cite: Khazan, Y. and Aryasova, O.: Plate tectonics is crucial for habitability of terrestrial planets, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3113, https://doi.org/10.5194/egusphere-egu26-3113, 2026.

Earth's climate has changed in many ways over the past 4+ gigayears (Gyr), while mostly sustaining temperate conditions via volatile cycling.  This is remarkable given that the Sun's luminosity has changed by almost 30% in 4 Gyr.  The Earth's rotation rate has also changed by a factor of nearly 2 due to the receeding of the moon from Earth and changing bathymetry affecting tidal dissipation.  The climate of deep time future Earth (+1-3 Gyr) has seldom been explored, but one can use Earth's distant past to help inform us. The Sun's luminosity will continue to increase, while the moon's orbit will continue to grow affecting tidal dissipation in whatever bathymetry the Earth has in the future.  Using the ROCKE-3D climate model and VPlanet orbital dynamics components we attempt to model the future climate of Earth and how it might inform us about similar worlds orbiting nearby stars. For example, in one modeled dynamical scenario 1.9Gyr into the future the Earth's length of day (LoD) will increase to 46 days, while it's obliquity will approach zero. The global mean surface temperature (GMST) will only be 7.6C. If we choose a less dissipative scenario we find a LoD=1.5 days, an obliquity of 27.5, and a GMST=40C!  Will Earth eventually enter a moist and then a runaway greenhouse, or will it remain a temperate world until the Sun's red giant phase engulfs it in another 5 gigayears?  We will attempt to provide some answers to these questions.

How to cite: Way, M. and Barnes, R.: The Climate Evolution of Earth's Distant Future and implications for eta Earth, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6124, https://doi.org/10.5194/egusphere-egu26-6124, 2026.

 Validated temporal gradient-driven gas migration on Earth as the primary mechanism for repeatable methane fluctuations on Mars.

By

Hovav Zafrir¹, Yuval Reuveni², Ayelet Benkovitz², Zeev Zalevsky¹, Elad Levintal³, Noam Weisbrod³,Danielle Ilzycer⁴

¹ Faculty of Engineering, Bar Ilan University, Ramat-Gan 5290002, Israel

²Department of Physics, Ariel University, Ariel 4070000, Israel

³The Jacob Blaustein Institutes for Desert Research, BGU University, of the Negev, Sede Boker, Israel

⁴Soreq NRC, Yavne, Israel

ABSTRACT

A significant observation by Curiosity’s Tunable Laser Spectrometer in Mars' Gale Crater involves repeatable methane fluctuations with distinct seasonal and sub-diurnal variability. After a decade of data, these methane emissions clearly require robust geophysical explanations rooted in thermodynamics.

On Earth, extensive field and laboratory research have demonstrated that surface temperature gradients primarily drive subsurface gas flows, particularly those of Radon-222. This thermally induced transport exhibits an exponential dependence, verified through long-term field measurements (4 years (*)) and also in controlled laboratory conditions, where oscillating vertical gas flow closely matches surface heating cycles, from the natural one per day to one per eight days. The field monitoring has shown that radon gas flows downward throughout all daylight hours within the bedrock to a measured depth of 100 meters and responds inversely to atmospheric temperatures at night, creating an inverted surface temperature gradient that drives nocturnal exhalation.

While gases on Earth's ground also respond linearly to semi-diurnal barometric pressure changes (barometric pumping), within cracks, voids, or fractures between geological layers and structures, our experience indicates that such effects become negligible when the pressure gradient is less than 2 millibars. Specifically, on Mars, where barometric pressure is two orders of magnitude lower than Earth's, the resulting pressure gradient is insufficient to drive significant gas transport, even through sand on Earth's surface.

^(*) Benkovitz et al., 2023, https://doi.org/10.3390/rs15164094. Zafrir, et al., 2016, https://doi. org/10.1002/2016JB013033.

How to cite: Zafrir, Dr. H., Reuveni, Y., Benkovitz, A., Zalevsky, Z., Levintal, E., Weisbrod, N., and Ilzycer, D.: Validated temporal gradient-driven gas migration on Earth as the primary mechanism for repeatable methane fluctuations on Mars., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14723, https://doi.org/10.5194/egusphere-egu26-14723, 2026.

Radar remote sensing is essential for investigating Venus’ surface due to its dense CO₂-rich atmosphere and permanent cloud cover. The forthcoming ESA EnVision mission, equipped with the S-band VenSAR instrument operating in dual polarimetric HH and HV modes, will provide high-resolution observations to characterise surface scattering mechanisms, surface roughness, and dielectric properties. These observations are expected to enable the identification of signatures associated with active volcanic processes, including recent lava flow emplacement and surface alteration driven by thermal and chemical weathering. However, interpretation of polarimetric SAR observations over volcanic terrains remains challenging due to strong surface roughness, structural anisotropy, and orientation angle-induced depolarisation effects. Terrestrial volcanic analogues therefore provide a suitable framework for the development and validation of physically consistent polarimetric models prior to the availability of VenSAR data. This study presents a technical analysis of polarimetric scattering mechanisms at the Sundhnúksgígar and Holuhraun volcanic sites in Iceland using dual and full polarimetric ALOS-PALSAR-2 L-band SAR datasets. Fully polarimetric observations are used to quantify dominant scattering contributions and to evaluate the performance of conventional model-based decomposition approaches, including Freeman-Durden and Yamaguchi decomposition, over rough and structurally complex lava surfaces. To address the systematic overestimation of volume scattering, which can cause rough aa lava flows to be misclassified as vegetation, a modified model-based decomposition technique is introduced. By redistributing cross-polarised backscatter as a function of surface roughness, the proposed approach improves the separation of scattering mechanisms and enables more accurate discrimination of lava flow units and volcanic surface textures across both study areas. In addition, a dual polarimetric analogue of the proposed model-based decomposition technique is developed to enable volcanic surface characterisation using reduced polarimetric configurations consistent with the EnVision VenSAR acquisition mode. Multi-temporal ALOS PALSAR 2 dual polarimetric acquisitions are analysed to investigate surface evolution and volcanic dynamics associated with lava emplacement, flow cooling, and post-eruptive surface modification at the Sundhnúksgígar volcano site. The dual polarimetric formulation demonstrates strong correspondence with full polarimetric results in terms of dominant scattering behaviour and spatial variability, supporting the applicability of the proposed framework for future Venus observations. These results provide a validated polarimetric approach for characterising volcanic surfaces and contribute directly to the scientific preparation and exploitation of EnVision VenSAR data.

Keywords: Volcanos; SAR Polarimetry; Polarimetric SAR Decomposition; EnVision; ALOS-PALSAR-2; VenSAR

How to cite: Awasthi, S., Gao, Y., Gallardo i Peres, G., Davidova, N., C. Ghail, R., and Mason, P. J.: Polarimetric Characterisation of Volcanic Surfaces Using Dual and Full Polarimetric Spaceborne SAR Datasets: Analogue Studies for the Venus’s EnVision Mission, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20877, https://doi.org/10.5194/egusphere-egu26-20877, 2026.

Faults provide key evidence for a planet’s tectonic history, especially where direct geophysical data are scarce. Fault geometry analysis is essential for understanding tectonic deformation [1] and seismic potential [2]. Thorough fault geometry analysis constraints fault evolution mechanical response [3,4]. Marsquakes at Cerberus Fossae, Mars [5] which were detected by InSight mission’s seismometer renewed interest in Martian tectonics, and underscored the significance of extensional fault systems. Memnonia Fossae is a region hosting prominent extensional structures similar to Cerberus Fossae. Yet, these structures in Memnonia Fossae are much older than the ones in Cerberus Fossae, which provides a valuable opportunity to explore the long-term evolution of fault systems on Mars. However, due to the challenges in obtaining high-resolution topographic data [6], fault geometry studies on Mars are still limited. Therefore, to address this limitation, we use the Reykjanes Peninsula in Iceland as a terrestrial analogue, where active tectonic processes in basaltic terrains reflects those believed to occur on Mars. The objective of this study is to evaluate and compare the geometric properties and scaling relationships of normal faults in Memnonia Fossae region on Mars and Reykjanes Peninsula in Iceland, providing insights into fault growth mechanisms at a planetary scale.

Previously, we obtained a maximum displacement-to-length (D_max/L) ratio of 0.007 by analyzing fault scaling in Memnonia Fossae using remote sensing data from 100 faults. In this study, we focused on the Reykjanes Peninsula, and we collected structural measurements from 74 faults and fractures across 180 locations, recording parameters such as strike, dip, opening throw, shear, and extension vectors. Alongside field measurements, the Arctic DEM and drone imagery were employed also for less accessible faults.  The integration of field measurements, remote sensing, and drone imagery enabled a detailed characterization of fault geometry and displacement. The D_max/L ratio derived from Reykjanes peninsula was 0.006, closely corresponding to values derived for Memnonia Fossae and aligning with fault scaling observation in volcanic terrains on Earth. The observed similarities between faults in Reykjanes and Memnonia Fossae indicate that comparable fault growth processes may operate in both regions despite differences in age and origin. Reykjanes faults are part of an active plate-boundary rift zone on Earth, whereas Memnonia faults formed in the ancient crust of a single-plate planet. Comparing older and younger faults offer insights into the tectonic evolution of Mars and demonstrates the value of Earth-based multi-source datasets in planetary studies.

Figure 1: Dmax/L ratio comparisons of Memnonia Fossae, Reykjanes, and volcanic rocks on Earth [7].

[1] Schultz, R.A. et al. (2010) J. Struct. Geol., 32, 855-875. [2] Wells, D.L. and Coppersmith, K.J. (1994) Bull. Seismol. Soc. Amer., 84, 974-1002. [3] Cartwright, J. A., et al., (1995) J. Struct. Geol. 17, 1319-1326. [4] Cowie, P.A. and Scholz, C.H., (1992) J. Struct. Geol. 14, 1133-1148. [5] Drilleau, M., et al., (2021) EGU General Assembly. Conf. 14998. [6] Gwinner, K. et al., (2010) Earth Planet. Sci. Lett. 294, 506-519. [7] Lathrop, B. A., et al., (2022) Frontiers in Earth Science, 10, 907543.

How to cite: Yazıcı, I. S., Kenkmann, T., Sturm, S., Karagoz, O., Hauber, E., and Tirsch, D.: From Iceland to Mars: Fault Scaling and Tectonic Insights from an Earth Analogue, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21129, https://doi.org/10.5194/egusphere-egu26-21129, 2026.

The physical behaviour of silicate magmas and their eruptive style are strongly controlled by melt structure, volatile content, and cooling conditions, reflected in spectral properties. Magma rheology and eruptive style are primarily controlled by volatile-driven modifications of melt structure (especially due to H₂O), which govern fragmentation during magma–water interactions, producing fine, lithic-rich tephra. Spectroscopic techniques provide a powerful means to investigate melt structure and pre-eruptive volatile contents, offering insights into eruption dynamics.
We analysed tephra samples from two phreatomagmatic successions on Vulcano Island (Aeolian Arc, Italy), a natural laboratory to investigate relationships among magma composition, volatile content, and eruption style (Keller, 1980; De Astis et al., 1997). Eleven ash-rich layers were sampled. Field measurements included VNIR reflectance spectra acquired with an ASD FieldSpec spectroradiometer and portable Raman spectroscopy. Diffuse reflectance FTIR spectra were collected using a Bruker Invenio X spectrometer on natural and oven-dried samples (105 °C, 48 h) to evaluate adsorbed water. Quantitative spectral parameters were extracted, including band center, full width at half maximum, and area under the curve in the 300–25000 nm domain. We investigate whether VNIR reflectance spectroscopy and laboratory FTIR measurements can identify spectral criteria diagnostic of eruption style in surge-dominated pyroclastic deposits. Preliminary analyses reveal systematic spectral variations related to volatile content and silicate melt structure. The spectra display absorption features attributed to Fe³⁺, molecular H₂O, OH⁻, Al–OH, and Fe–OH vibrations, enabling extraction of band parameters sensitive to hydration state and polymerization degree. Thermal treatment experiments show reduced band areas and spectral slope associated with H₂O and OH⁻ absorptions after heating, indicating that most water in natural samples is weakly bound or adsorbed. However, water loss varies among stratigraphic levels, reflecting differences in glass content, porosity, and hydration history. Variations in Si–O and Al–O band positions and widths indicate differences in silicate network polymerization, with narrower bands and shifts toward higher wavenumbers consistent with evolved compositions. Overall, the spectral signatures are consistent with highly explosive eruptions involving water-rich, evolved magmas and record internal heterogeneity within the eruptive column, marked by progressive degassing during the eruptive event.
This study contributes to the development of spectral reference datasets of terrestrial volcanic materials, essential for interpreting remote sensing data. By linking spectral features to the physical and chemical characteristics of volcanic deposits and their eruptive context, we constrain the nature of volcanic activity on other planetary bodies.

De Astis, G.F. et al., 1997. Volcanological and petrological evolution of the Vulcano Is land Aeolian arc, southern Tyrrhenian Sea. J. Geophys. Res. 102, 8021–8050.
Keller, J., The island of Vulcano, Rend. Soc. Ital. Mineral. Petrogr., 36, 369–414, 1980

How to cite: Gentili, C., Tiraboschi, C., Pisello, A., Baroni, M., Ortenzi, G., Baqué, M., Bohnhardt, T., and Perugini, D.: From terrestrial volcanic ashes to planetary surfaces:FTIR spectral constraints on eruption style from surge deposits from Vulcano Island (Italy), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21130, https://doi.org/10.5194/egusphere-egu26-21130, 2026.