In the search for extraterrestrial intelligence (SETI), it is often assumed that intelligent life on an Earth-like exoplanet would inevitably develop the technological means for interstellar communication. This assumption ignores the critical role that fossil fuels played in driving the Industrial Revolution on Earth, which ultimately gave rise to our own advanced technological civilization (ATC) and the possibility of interstellar communication. We therefore propose that any habitable exoplanet that could potentially generate an ATC must contain sizable fossil fuel deposits, especially coal, which supplied most of the energy used in the Industrial Revolution during the 19th century. Coal is critical because, based on an Earth-like geology, it is more accessible than the much deeper deposits of oil and gas. Without coal, it would have been impossible to tap into the vast underground deposits of oil and gas during the 20th century. This raises the question of the inevitability of coal formation on an Earth-like exoplanet. Here we present arguments that coal formation may be unlikely, even on an Earth-like planet, because of the many contingent factors that have been recorded in the rock and biological record of our own planet, including the evolution of oxygenic photosynthesis itself, which generated the oxygen-rich atmosphere required for complex life to develop. Central to our argument is the host of highly contingent taphonomic factors, involving plate tectonics and climate, that were required to convert the tropical lycopsid swamp forests of the Pangean supercontinent to the massive coal deposits of the Carboniferous period. Finally, we discuss the need for synchronicity of the appearance of intelligent life forms and the maturation of vast deposits of coal. We conclude that the large number of contingencies involved in coal production justifies adding a term for coal to the Drake Equation for the number of ATCs in the galaxy.

Since its foundation in 2001, EANA (European Astrobiology Network Association, http://www.eana-net.eu/) has organized annual meetings to foster and strengthen the astrobiology community within Europe. The growth of the European astrobiology community over the years is reflected not only in the growing participation at the annual EANA meeting but also in the foundation of the graduate network AbGradE (Astrobiology Graduates in Europe, https://abgrade.eu/) with many activities, meetings and workshops organized since 2014, including several joint events with EPEC (the EuroPlanet Early Career network), as well as the foundation of the European Astrobiology Institute (EAI) in 2019.

The EANA Executive Council consists of national representatives from currently 21 European (and affiliated) countries with active astrobiology groups, networks or societies, as well as representatives of the early-career AbGradE network. The EANA network and especially the Executive Council therefore directly promote a broad and diverse representation of many career stages as well as nationalities including normally underrepresented countries. After more than two decades of a formal astrobiology network in Europe, it is time to explore and evaluate the actual obtained diversity within EANA and AbGradE with respect to nationality, gender and career status of our members based on our annual meeting participation, and to reflect on future measures to further improve the diversity and inclusiveness of our networks and events.

We find that while our annual events are very diverse with respect to career stage, gender and research disciplines, a few aspects leave room for improvement, including especially a more balanced representation of different countries with astrobiology research within Europe and beyond. We discuss different equality, diversity and inclusivity measures that can be implemented for future EANA and AbGradE meetings in Europe to better represent the full astrobiology community within our networks.

The present study has set up a pilot experiment to optimise the most promising assays for investigating the survival of Antarctic microbial cryptoendolithic communities – a natural astrobiological benchmark – when subjected to lethal/sub-lethal stresses testing viability, cell integrity and metabolic activity. Namely, the viability tests for culturable species are based on cultivation on a solid medium, while qPCR coupled to propidium monoazide (PMA) provides information of both culturable and non-culturable microorganisms. The fluorescein diacetate (FDA) and Adenosine 5’-TriPhosphate (ATP) assays, here optimised, consent to highlight the presence of metabolically active cells. The results revealed significant differences between the treated and untreated samples, proving the suitability of the selected tests for investigating the resilience of these astrobiological models.

Studying exoplanetary atmospheres offers critical insights into chemical compositions, temperature profiles, cloud formations and atmospheric dynamics. Carbon monoxide (CO), an important molecule in biology and astronomy, exhibits distinct spectral features and could be considered a potential biosignature. This work compares the spectral bands of gases emitted by Roseovarius sp. (obtained from the Atacama desert) and theoretical model atmospheres simulating early Earth analogs. We obtained Raman and infrared spectra of the bacteria. Theoretical model atmospheres of early Earth analogs were generated for comparative spectral analysis. The spectra of Roseovarius sp. revealed distinct vibrational modes, including CO at 5.01 $\mu $m (1996 cm−1) which is considered in the context of other biogenic gases in the metabolism of Roseovarius sp. Ultracool dwarf stars, especially those of spectral type M7 and later, are prime targets for observing habitable exoplanets due to their small radii. The James Webb Space Telescope (JWST) and extremely large telescopes (ELTs) will enable the spectroscopic characterization of Earth-like planets orbiting M-dwarfs. Future studies using the JWST sensitivity models PandExo could estimate the number of transits needed to detect CO/CO2 in rocky exoplanet atmospheres, enhancing our understanding of CO detectability.

Bioregenerative life support systems (BLSS) designed to produce food crops in future crewed missions to the Moon or Mars consider in-situ resource utilisation (ISRU). Lunar regolith is, therefore, in focus for future technologies of farming on lunar bases. We tested germination and early growth of broccoli plants (Brassica oleracea var. botrytis italica) in Murashige-Skoog liquid medium with addition of leachate from a lunar regolith simulant. As the additions to growth, differently diluted water and acidic leachates were used. Physiological status of the germinating plants was evaluated by chlorophyll fluorescence parameters related to plant vitality (relative fluorescence decline – Rfd) and photosynthetic performance of photosystem II (1) potential (FV/FM) and (2) effective quantum yield of PSII (ΦPSII), photochemical quenching referring to number of open PSII reaction centres. Both water and acidic leachates inhibited plant growth, however, the extent of growth limitation was dilution-dependent. Full inhibition of germination was apparent when undiluted acidic leachate was added. However, 50% dilution (and higher) resulted in seed germination and the early growth. No negative effects of the water dilutions on FV/FM as well as ΦPSII, were apparent in 15 days old plants, their cotyledonary and the first primary leaves, in particular. Similarly, qP and Rfd showed no sign of either water or acidic leachate addition effect. Although photosystem II-related parameters exhibited no negative effect of the leachates addition, a growth of plants was found dilution-dependent: higher degree of dilution resulted in a more pronounced reduction in plant projection area. In spite of the growth rate reduction (compared to untreated control), properly diluted water and acidic leachates from lunar regolith and/or its simulants might be used in follow up studies focused on plant species prospective for future cultivation in Moon-based stations with temporary or permanent crew.

Carbonaceous chondrites contain various organic compounds, including amino acids (AAs), which may have contributed to the emergence of life on Earth. However, their origin remains debated. Previous studies have shown that amino acid precursors (AAPs) can form in ice mantles of interstellar dust particles within molecular clouds. These AAs and AAPs could have been incorporated into small celestial bodies during the formation of the solar system. It has been suggested that interstellar AAs and AAPs underwent aqueous alteration due to heat and radiation from the decay of radioactive nuclides such as 26Al. To test this hypothesis, we combined experiments simulating interstellar chemical reactions with those mimicking conditions inside meteorite parent bodies. We subjected AAs and interstellar AAP analogs to gamma irradiation in mixtures of formaldehyde (HCHO), methanol (CH3OH), ammonia (NH3) and water (H2O). The resulting products were analyzed by cation-exchange high-performance liquid chromatography (HPLC) and gas chromatography-quadrupole mass spectrometry (GC/MS). Our results demonstrated that interstellar AAP analogs were more resistant to gamma irradiation than free AAs. Among the free AAs, glycine exhibited the highest stability, while AAs lacking α-hydrogens were more stable than their isomeric counterparts with α-hydrogens. Additionally, gamma irradiation not only degraded AAs but also generated new ones. The yield and diversity of newly formed AAs depended on the specific AAPs or AAs present in the system. Notably, systems containing interstellar AAP analogs produced a greater variety and higher quantity of AAs than those containing free AAs or none at all. These findings suggest that interstellar organic matter, including AAPs, delivered to asteroids could have contributed to the formation of the diverse organic compounds observed in asteroids and meteorites.

Previous publications by the authors put forward the argument that Lifelike Cellular Automata (LCAs) can be treated as a bona fide example of livingness in and of themselves, not simply a toy analogue to biological life. Traits known to be indicative of biological life – biosignatures – were identified in informational form as particular outlier traits of the ruleset for the LCA known as Conway’s Game of Life (CGOL). This publication reverses that logic, looking at a known outlier trait of CGOL – its very long-lasting evolutions – and using this to point towards temporal retention as an informational biosignature concept.

Between 2.4 and 0.6 Gy ago, our planet underwent several episodes of global glaciations, including the “Snowball Earth” case that ended 635 My ago. Causes of this last Snowball event presumably included a decreased greenhouse gas concentration and high continental albedo, both associated with the passage of the super-continent Rodinia at equatorial latitudes. When large continental masses are in equatorial regions, silicate weathering is enhanced, leading to decreased atmospheric CO2 concentration, while the bare continental masses, which at the time hosted no vegetation, enhanced reflection of solar radiation. Since then, no other Snowball episodes were recorded. Here we numerically explore the climatic dynamics of a rocky planet for different values of solar output, continental configuration (current and Rodinia-like), CO2 concentration and continental albedo, simulating the effects of land vegetation. We found that for the solar input typical of 600–700 My ago (95% of the current value), the presence of bare continents with albedo 0.35 (granite) in the position estimated for Rodinia was sufficient to trigger a Snowball state for CO2 concentrations up to at least 1000 ppm. When bare continents are located in modern positions, Snowball could be triggered only for values of CO2 concentration below 400 ppm. At current solar input values, Snowball states appear only at or below 100 ppm. Thus, we found that (a) a lower solar output is an essential component of the transition to Snowball; (b) the presence of land vegetation is crucial and reduces the probability of entering a Snowball state; (c) a low CO2 concentration was not needed for triggering a Snowball in bare Rodinia-like conditions and reduced solar output; and (d) current solar luminosity does not allow Snowball states, even for equatorial continents, unless continental albedo is that of granite and CO2 concentration is 100 ppm or less.

Extreme environments are places where sustaining life is considered challenging by human standards due to harmful environmental conditions. In the last decades, these kinds of environments have awakened the interest of planetary scientists due to their similar conditions to extraplanetary bodies. Most of the research done in extreme environments has been conducted in the North American and Eurasian regions, while in Latin America only the most outstanding places have been explored, even though the region hosts numerous and varied extreme environments. The primary aim of this review is to present an extensive catalogue of around 300 extreme environments in Latin America. We classify them into deserts and semi-arid environments, geothermal and hydrothermal environments, glaciers and high mountain environments and hypersaline environments. Our review found that a great number of those environments remain unexplored or partially studied; however, many of those environments show multi-extreme features, becoming suitable to conduct astrobiology experiments such as biosignatures detection or planetary analogue missions. This review brings to current and future researchers a summary of the environmental properties of each place and their respective locations, to promote astrobiology and planetary science research in Latin America.

The paper discusses the possibility of dust particles containing living bacteria ejected from Earth reaching Europa and landing on its surface. It is shown that, taking certain factors into account, over a period of 30 − 80 Myr (the estimated age of Europa’s ocean), Jupiter’s moon would have been impacted by approximately 3 × 1023 to 8 × 1023 particles in total, within which a bacterium could have survived. In the paper, we discuss the possibility of dust grains entering liquid water beneath the surface.

The purpose of this review is to examine the historical background and the scientific and philosophical foundations underlying the emergence and development of Russian astrobiology. In addition, it seeks to provide the international scientific community with a comprehensive account of the principal achievements of the Russian scientists whose research has contributed to the field of astrobiology. Their contributions include experimental models of prebiotic synthesis and impact-generated organics; the formulation of original theories of life’s origin; investigation of cold and glacial terrestrial ecosystems as analogs for Mars and celestial icy bodies; advances in bacterial paleontology with significant astrobiological implications. A significant amount of data produced by Soviet scientists were published exclusively in Russian journals and therefore remained largely inaccessible to the international scientific community. The review also discusses the current state and principal scientific directions of Russian astrobiology, its international cooperation, the challenges and prospects it faces, and provides a comparative analysis with the development of astrobiology in Western countries. Its primary aim is to outline the fundamental structure of astrobiology research in Russia from a retrospective perspective.

We present an exploratory framework to test whether noise-like input can induce structured responses in language models. Instead of assuming that extraterrestrial signals must be decoded, we evaluate whether inputs can trigger linguistic behavior in generative systems. This shifts the focus from decoding to viewing structured output as a sign of underlying regularity in the input. We tested GPT-2 small, a 117M-parameter model trained on English text, using four types of acoustic input: human speech, humpback whale vocalizations, Phylloscopus trochilus birdsong and algorithmically generated white noise. All inputs were treated as noise-like, without any assumed symbolic encoding. To assess reactivity, we defined a composite score called semantic induction potential, combining entropy, syntax coherence, compression gain and repetition penalty. Results showed that whale and bird vocalizations had higher SIP scores than white noise, while human speech triggered only moderate responses. This suggests that language models may detect latent structure even in data without conventional semantics. We propose that this approach could complement traditional Search for Extraterrestrial Intelligence methods, especially in cases where communicative intent is unknown. Generative reactivity may offer a different way to identify data worth closer attention.

We propose a novel method for estimating possible biological evolutionary stage on exoplanets based on the hypothesis that biological evolutionary state is a linear function of cumulative carbon fixed (photosynthesis) on an entire planet. We explore the implications of this hypothesis using spatially explicit climate simulations of TRAPPIST-1e, a tidally locked planet within the habitable zone of a red dwarf star ∼40 light years away. We estimate that Earth has cumulatively fixed ∼9.4 e25 g C carbon, and TRAPPIST-1e (T1e) as an ocean world with 400 ppm CO2 using photon energy of wavelengths 400–1100 nm would need 18 Gyr years to fix the same amount of carbon. Since T1e’s mean estimated age is 7.6 Gyr, we estimate it to be at a potential microbial, but not multicellular life stage. We then apply this technique to 29 nearby exoplanets that may have the conditions suitable for harboring life, using 400–1100 nm light and assuming a 30% continent ratio. We identify two planets that surpass Earth’s cumulative Net Primary Production (NPP) and which could have both multicellular and intelligent life and 6 planets at the potential multicellular stage. Planets most likely to have higher cumulative NPP than Earth are also most likely to be dominated (more than Earth) by precipitation limited ecosystems, like deserts or temperate ecosystems (versus boreal or tropical ecosystems). Planets GJ 1061c and K2-3d rank highest in cumulative productivity potential under a number of our scenarios because they are bigger, hotter, brighter and older than other planets in the solar neighborhood.

The development of organic biosignature analysis instruments with picomolar (pM) sensitivity is necessary for meaningfully exploring our solar system for habitability and for organic chemical biomarkers. To address this challenge, the Microfluidic Organic Analyzer (MOA) prototype has been redesigned and reengineered in a compact, low-mass, space-flight ready format. To evaluate the performance of the flight-format MOA instrument, we performed a series of Zero-G parabolic aircraft flights to test the microfluidic fluid processing, capillary electrophoresis (CE) separation, and detection systems in a diverse range of micro- and hyper-gravity environments. Amino acid CE separations were performed in flight to assess the protocols and to determine the dependence of the separation quality on large variations in gravitational potential. We present here amino acid separations performed as the gravitational potential varied from 0.16 to 1.7 g during the separation. When the flight profile enabled proper preparation, the separation was indistinguishable from separations performed in a constant 1 g environmental control with the same reagents. This work advances the technology readiness of the MOA for performing in situ organic analyses relevant to habitability and biosignatures — an important step toward deploying picomolar sensitivity in the search for extraterrestrial biomarkers.

The contested 2020 report of phosphine in Venus’s atmosphere triggered one of the most prominent recent debates in astrobiology, raising the possibility of extraterrestrial life while exposing deep scientific uncertainty. This study examines how English-language news media communicated this uncertainty over time and across news outlet types. Drawing on a standardized content analysis of news coverage published between September 2020 and June 2025, we trace shifts in uncertainty framing across four periods of the scientific debate. Findings show that media coverage was closely aligned to the scientific agenda. However, media reports – particularly during the initial discovery period – often expressed greater certainty about both phosphine and extraterrestrial life than was apparent in exemplary scientific publications. Consensus uncertainty was the most prominent uncertainty frame, accurately reflecting expert disagreement while posing potential challenges for public trust. Media types differed markedly, with mass-market media exhibiting more sensational framing and specialist science outlets adopting greater epistemic caution. Notably, clickbaiting strategies were relatively rare across the sample. Together, the findings show how media coverage selectively communicates and contextualizes uncertainty in reporting on frontier science.

Caves serve as terrestrial analogues for extraterrestrial subsurface environments: permanently dark, nutrient-poor and physicochemically stable on biologically relevant timescales. Morca Cave (Anamur, Mersin, Türkiye) extends to depths below 1200 m and is one of Türkiye’s deepest and least disturbed cave systems. Within our study, Gram-positive bacteria dominated at four of the five sampling sites (64.4–86.7%), while Gram-negative bacteria predominated at only one site (51.4%). Thirty-nine isolates produced visible yellow or orange pigmentation under laboratory conditions and were selected for further characterisation. Thin-layer chromatography detected xanthophyll-type pigments in 35 of these 39 isolates and a β-carotene-range spot in 22. HPLC tentatively identified a lutein-like xanthophyll in 36 of 39 isolates at concentrations of 1.34–34.65 ppb. Only two isolates yielded quantifiable HPLC peaks tentatively assigned to putative β-carotene; the remaining high-Rf TLC bands likely correspond to other apolar carotenoids. All pigment identifications are tentative, based on TLC and HPLC matching against authentic standards, and require LC-MS/MS or NMR confirmation. 16S rRNA gene sequencing assigned 31 of the 39 pigmented isolates to known taxa. Actinomycetia accounted for 20 isolates, Betaproteobacteria for six, Alphaproteobacteria for two, Bacilli for two and Gammaproteobacteria for one. Lutein-like pigment was recovered from bacteria isolated from surface samples at all three depths (−400, −620, −680 m) and from sediment samples at −400 and −620 m under standard heterotrophic cultivation; these isolates therefore retain biosynthetic capacity for carotenoid production independent of light. To our knowledge, this is the first study combining carotenoid profiling with 16S rRNA gene-based taxonomic assignment across a vertical depth gradient in a Turkish deep-karst cave system. The pigment concentration ranges and taxonomic distribution reported here provide an initial empirical reference dataset for carotenoid biosignature research in aphotic, oligotrophic subsurface environments proposed as terrestrial analogues for Mars and icy-moon habitability studies.

Mitigating the forward contamination of Mars in the vicinity of a landed spacecraft is a significant concern for future life-detection experiments. Here we model the dispersal of bacterial cells or spores (henceforth spores) from a single dispersal event at landing that injects 100 viable spores to a height of 100 m followed by settling of the spore plume under no-wind or windy scenarios. Subsequent to the single dispersal event, it is assumed that all spores remain viable during dispersal, during their residence time on the surface terrain and throughout the eventual collection of regolith or rock samples. The highest risk for recovering one viable spore after dispersal is in a circle with a radius of 10 m, under a no-wind scenario, and approaches a probability (P) of ≤ 1 × 10−3. If the spores are lofted with a wind at 1 m/s, the P values for recovering one spore range between 1 × 10−5 at 20 m and 5 × 10−8 at 500 m downwind, respectively. As the wind speeds increase to 10 m/s, the dispersal cones increase downwind to over 7000 m and their aspect ratio narrows significantly. At 10 m/s, P approaches ≤ 1 × 10−9 for recovering one viable spore at 7000 m. If a rover is landed and the traverse is orthogonal to the downwind spore dispersal plume, P = 0, except where sampling vibrations of the rover arm might create secondary dispersal events. Results suggest that the risks of false positives in life-detection experiments from dispersed spores are very low.