Moon Titan Research Articles

Evaluating the Use of Unoccupied Aircraft Systems (UASs) for Planetary Exploration in Mars Analog Terrain

Planetary analog mission simulations are essential for testing science operations strategies and technologies. They also teach us how to use terrestrial analogs to inform studies of extraterrestrial environments. Unoccupied aircraft systems (UASs) have great potential for planetary surface exploration as demonstrated by the Mars 2020 Ingenuity helicopter and the in-development Dragonfly mission to Saturn’s moon Titan. Although applications of UAS technology for planetary exploration remain largely unexplored, simulated missions in planetary analog terrains can inform operational best practices. As part of the Rover–Aerial Vehicle Exploration Network project, we simulated a 12 sol UAS mission on Mars in the Holuhraun region of Iceland. The UAS had airborne imaging capability, as well as imaging, sampling, and geochemical analysis capabilities while landed. The mission evaluated the use of these instruments and developed operational strategies for using UASs to explore a planetary surface. Oblique airborne images were essential for mission planning and were used to scout large areas to identify both potential landing sites and targets for focused investigations. The airborne and landed data collected by the UAS allowed for detailed observations and interpretations not possible with analog orbital data sets, resulting in an improved scientific return for the simulated UAS mission compared to a premission analysis of only the analog orbital data. As a planetary exploration vehicle, a UAS is most advantageous for exploring large areas (many square kilometers) and is particularly useful when the terrain may be impassable to ground-based traverses (e.g., by rovers or humans).

Space Molecules in Superacidic Media─The Synthesis and Structure of Monoprotonated Cyanoacetylene and Diprotonated Dicyanoacetylene.

The molecules cyanoacetylene and dicyanoacetylene detected in the atmosphere of Saturn's largest moon Titan were investigated in superacidic media XF/MF5 (X = H, D; M = As, Sb), XF/GeF4, and XF/BF3. Cyanoacetylene is obtained as a monoprotonated salt, while only the diprotonated salt of dicyanoacetylene has been isolated. The salts were characterized by vibrational spectroscopy, NMR spectroscopy, and single-crystal X-ray diffraction. The protonations lead to a significant shortening of the C≡N bond. The salts of [C3HXN][SbF6] (X = H, D) show very rare coupled oscillations in vibrational spectroscopy. The experimental results are discussed together with quantum chemical calculations at the M062X/aug-cc-pVTZ level of theory. The -M and -I effects of the C≡N moiety decrease by protonation of the nitrile moiety.

Unveiling the Reaction Mechanism of the N(2D) + Pyridine Reaction: Ring-Contraction versus 7-Membered-Ring Formation Channels.

Despite the relevance of the reactions of the prototypical nitrogen-containing six-membered aromatic molecule (N-heterocyclic) of pyridine (C6H5N) in environmental science, astrochemistry, planetary science, prebiotic chemistry, and materials science, few experimental/theoretical studies exist on the bimolecular reactions involving pyridine and neutral atomic/molecular radicals. We report a combined experimental and theoretical study on the elementary reaction of pyridine with excited nitrogen atoms, N(2D), aimed at providing information about the primary reaction products and their branching fractions (BFs). From previous crossed molecular beam (CMB) experiments with mass-spectrometric detection and present synergistic calculations of the reactive potential energy surface (PES) and product BFs we have unveiled the reaction mechanism. It is found that the reaction proceeds via N(2D) barrierless addition to pyridine that, via bridged intermediates followed by N atom "sliding" into the ring, leads to 7-membered-ring structures. They further evolve, mainly via ring-contraction mechanisms toward 5-membered-ring radical products and, to a smaller extent, via H-displacement mechanisms toward 7-membered-ring isomeric products and their isomers. Using the theoretical statistical estimates, an improved fit of the experimental data previously reported has been obtained, leading to the following results for the dominant product channels: C4H4N (pyrrolyl) + HCN (BF = 0.61 ± 0.20), C3H3N2 (1H-imidazolyl/1H-pyrazolyl) + C2H2 (BF = 0.11 ± 0.06), and C5H4N2 (7-membered-ring molecules or pyrrole carbonitriles) + H (BF = 0.28 ± 0.10). The ring-contraction product channels C4H4N (pyrrolyl) + HCN, C3H3N2 (1H-imidazolyl) + C2H2, C3H3N2 (1H-pyrazolyl) + C2H2, and C5H5 (cyclopentadienyl) + N2 have statistical BFs of 0.54, 0.09, 0.11, and 0.07, respectively. Among the H-displacement channels, the cyclic-CHCHCHCHNCN + H channel and cyclic-CHCHCHCHCN2 + H are theoretically predicted to have a comparable BF (0.07 and 0.06, respectively), while the other isomeric 7-membered-ring molecule + H channel has a BF of 0.03. Pyrrole-carbonitriles and 1H-ethynyl-1H-imidazole (+ H) isomeric channels have an overall BF of 0.03. Implications for the chemistry of Saturn's moon Titan and prebiotic chemistry, as well as for understanding the N-doping of graphene or carbon nanotubes, are noted.

Surface properties of the seas of Titan as revealed by Cassini mission bistatic radar experiments

Saturn’s moon Titan was explored by the Cassini spacecraft from 2004 to 2017. While Cassini revealed a lot about this Earth-like world, its radar observations could only provide limited information about Titan’s liquid hydrocarbons seas Kraken, Ligeia and Punga Mare. Here, we show the results of the analysis of the Cassini mission bistatic radar experiments data of Titan’s polar seas. The dual-polarized nature of bistatic radar observations allow independent estimates of effective relative dielectric constant and small-scale roughness of sea surface, which were not possible via monostatic radar data. We find statistically significant variations in effective dielectric constant (i.e., liquid composition), consistent with a latitudinal dependence in the methane-ethane mixing-ratio. The results on estuaries suggest lower values than the open seas, compatible with methane-rich rivers entering seas with higher ethane content. We estimate small-scale roughness of a few millimeters from the almost purely coherent scattering from the sea surface, hinting at the presence of capillary waves. This roughness is concentrated near estuaries and inter-basin straits, perhaps indicating active tidal currents.

Analysis of the rotationally-resolved 3.3 µm region of C2H4 in natural isotopic abundance

Ethylene (or ethene) is a natural gas compound present in our atmosphere but also in the atmospheres of outer solar system planets such as Jupiter, Saturn, Uranus, Neptune and Saturn's moon Titan. However, a better knowledge of spectroscopic parameters is needed for this molecule in order to detect its presence and/or to derive its accurate concentration. We present here a detailed analysis and modeling of the strongly absorbing ν9 and ν11 fundamental bands in the 3.3 µm region. Due to the complexity of the observed spectrum, we have built a polyad scheme taking into account some fundamental bands previously analyzed thanks to the tensorial formalism developed in Dijon for asymmetric-top molecules. A four polyad system has been settled and the last P3 polyad contains four vibrational states: ν9, ν11, ν2+ν12 and 2ν10+ν12. A first frequency analysis has been performed, leading to 3328 assignments with a root mean square of 5.927 × 10−3 cm−1 and a standard deviation of 1.965 using 88 adjusted parameters, and we have also adjusted line intensities of 2190 lines by adjusting 14 parameters with an overall Root-Mean-Square (RMS) deviation of about 3.77 %. A new linelist of calculated lines in the 2900−3300 cm−1 region has been added to the ECaSDa and we plan to integrate it to the HITRAN database.

Propyne: Determination of Physical Properties and Unit Cell Parameters under Titan-Relevant Conditions.

With its large size, dense atmosphere, methane-based hydrological-like cycle, and diverse surface features, the Saturnian moon Titan is one of the most unique of the outer Solar System satellites. Study of the photochemically produced molecules in Titan's atmosphere is critical in order to understand the mechanics of the atmosphere and, by extension, the interactions between atmosphere, surface, and subsurface water ocean. One example is propyne vapor, a photochemically produced species in Titan's upper atmosphere expected to condense in Titan's stratosphere at lower altitudes. Propyne may also be a trace species in Titan's stratospheric co-condensed ice clouds detected by the Cassini Composite InfraRed Spectrometer. Bulk structural characterization of propyne ice is currently incomplete and is lacking in published laboratory Raman spectra and X-ray diffraction data. Here, we present a laboratory characterization of propyne ice, including the first published X-ray diffraction and Raman spectroscopy results for propyne ice.

The Bombardment History of the Giant Planet Satellites

The origins of the giant planet satellites are debated, with scenarios including formation from a protoplanetary disk, sequential assembly from massive rings, and recent accretion after major satellite–satellite collisions. Here, we test their predictions by simulating outer solar system bombardment and calculating the oldest surface ages on each moon. Our crater production model assumes the projectiles originated from a massive primordial Kuiper Belt (PKB) that experienced substantial changes from collisional evolution, which transformed its size frequency distribution into a wavy shape, and Neptune’s outward migration, which ejected most PKB objects onto destabilized orbits. The latter event also triggered an instability among the giant planets some tens of Myr after the solar nebula dispersed. We find all giant planet satellites are missing their earliest crater histories, with the likely source being impact resetting events. Iapetus, Hyperion, Phoebe, and Oberon have surface ages that are a few Myr to a few tens of Myr younger than when Neptune entered the PKB (i.e., they are 4.52–4.53 Gyr old). The remaining midsized satellites of Saturn and Uranus, as well as the small satellites located between Saturn’s rings and Dione, have surfaces that are younger still by many tens to many hundreds of Myr (4.1–4.5 Gyr old). A much wider range of surface ages are found for the large moons Callisto, Ganymede, Titan, and Europa (4.1, 3.4, 1.8, and 0.18 Gyr old, respectively). At present, we favor the midsized and larger moons forming within protoplanetary disks, with the other scenarios having several challenges to overcome.

Measurements of Titan’s Stratospheric Winds during the 2009 Equinox with the eSMA

Saturn’s moon Titan possesses stratospheric zonal winds that places it among a sparse class of planetary bodies known to have superrotation in their atmospheres. Few measurements have been made of these speeds in the upper stratosphere, leaving their seasonal variations still not well understood. We examined observations made with the extended Submillimeter Array in 2009 March (L s = 355°) and 2010 February (L s = 5°), shortly before and after Titan's northern spring equinox. Cassini observations and atmospheric models find equinoctial periods to be especially dynamic. Zonal wind calculations, derived from the Doppler frequency shift of CH3CN near 349.4 GHz, yielded speeds of 128 ± 27 m s−1 in 2009 and 209 ± 48 m s−1 in 2010. We estimated the measured emission to originate from vertical altitudes of 336−88+112 km, equivalent to pressures of 3.8−3.4+19.2 Pa, commensurate with Titan’s upper stratosphere/lower mesosphere. This suggests a possible increase in zonal speeds during this period. The results are then compared to those from previous Cassini-inferred and direct-interferometric observations of winds, as well as general circulation model simulations, to form a more complete picture of the seasonal cycle of stratospheric zonal winds.

Energy yields for acetylenotrophy on Enceladus and Titan

Saturn's moons Titan and Enceladus appear to satisfy three key criteria for life: presence of liquid water, nutrient availability, and metabolic energy sources. Consequently, these ocean worlds are the focus of astrobiology research investigations that aim to assess the potential for life beyond Earth. One plausible source of metabolic energy on these moons is acetylene (C2H2), a simple organic compound that is the second most abundant photochemical product in Titan's atmosphere and has been identified as a likely constituent of Enceladus' ocean. Acetylenotrophy, or the microbial fermentation of acetylene, is utilized by microbes on Earth in a number of environments. Here, we have calculated the energy yield of acetylenotrophy to be 69–78 kJ/mol C within the oceans of Titan and Enceladus, greater than the widely considered, hydrogenotrophic methanogenesis, at 25–65 kJ/mol C. Therefore, we propose acetylenotrophy as a potential metabolism on these moons that should be considered in future astrobiology studies on worlds with abundant acetylene.

Nuclear quantum effects in the acetylene:ammonia plastic co-crystal.

Organic molecular solids can exhibit rich phase diagrams. In addition to structurally unique phases, translational and rotational degrees of freedom can melt at different state points, giving rise to partially disordered solid phases. The structural and dynamic disorder in these materials can have a significant impact on the physical properties of the organic solid, necessitating a thorough understanding of disorder at the atomic scale. When these disordered phases form at low temperatures, especially in crystals with light nuclei, the prediction of material properties can be complicated by the importance of nuclear quantum effects. As an example, we investigate nuclear quantum effects on the structure and dynamics of the orientationally disordered, translationally ordered plastic phase of the acetylene:ammonia (1:1) co-crystal that is expected to exist on the surface of Saturn's moon Titan. Titan's low surface temperature (∼90K) suggests that the quantum mechanical behavior of nuclei may be important in this and other molecular solids in these environments. By using neural network potentials combined with ring polymer molecular dynamics simulations, we show that nuclear quantum effects increase orientational disorder and rotational dynamics within the acetylene:ammonia (1:1) co-crystal by weakening hydrogen bonds. Our results suggest that nuclear quantum effects are important to accurately model molecular solids and their physical properties in low-temperature environments.

Organic Hazes as a Source of Life’s Building Blocks to Warm Little Ponds on the Hadean Earth

Over 4 billion years ago, Earth is thought to have been a hazy world akin to Saturn’s moon Titan. The organic hazes in the atmosphere at this time could have contained a vast inventory of life’s building blocks and thus may have seeded warm little ponds for life. In this work, we produce organic hazes in the lab in atmospheres with high (5%) and low (0.5%) CH4 abundances and analyze the solid particles for nucleobases, amino acids, and a few other organics using GC/MS/MS to obtain their concentrations. We also analyze heated (200°C) samples from the high methane organic haze experiment to simulate these particles sitting on an uninhabitable surface. Finally, we use our experimental results and estimates of atmospheric haze production as inputs for a comprehensive numerical pond model to calculate the concentrations of nucleobases from organic hazes in these environments. We find that organic hazes typically provide up to 0.2–6.5 μM concentrations of nucleobases to warm little ponds for potentially habitable Hadean conditions. However, without seepage, uracil and thymine can reach ∼100 μM concentrations, which is the present lower experimental limit to react these species to form nucleotides. Heating samples leads to partial or complete decay of biomolecules, suggesting that biomolecule stockpiling on the hot surface is unlikely. The ideal conditions for the delivery of life’s building blocks from organic hazes would be when the Hadean atmosphere is rich in methane, but not so rich as to create an uninhabitable surface.

Marine Cold Seeps As A Gateway Of Deep Subsurface Extremophiles To The Seafloor

In the Earth’s deep subsurface life is comprised exclusively of microorganisms, and estimates indicate 12-45% of the global prokaryotic biomass, on the order of 1029 microbes, is found in subseafloor sediments. Investigating how this enormous microbial biomass is maintained in the extreme habitats below seafloor is critical for understanding the rules of life in the deep biosphere. Furthermore, Earth’s subseafloor habitats often present analog environments detected in other planets such as the recently discovered “ocean worlds”, i.e., planetary bodies in our solar system which consist of large subsurface oceans including Saturn’s moons Titan and Enceladus and Jupiter’s moon Europa. Therefore, investigating life in and beneath Earth’s oceans remains at the forefront of the current astrobiological research endeavors. Despite the inhospitable nature of the subseafloor sedimentary realm, active microbial populations including bacteria capable of transforming into dormant endospores have been demonstrated to inhabit deeply buried anoxic sediments and oil reservoirs, permeable ocean crust, and around hydrothermal vents. These extreme habitats often remain physically connected to the seafloor by unique geological features such as marine cold seeps that transmit hydrocarbon-rich fluids originating in deep sediment layers. It remains unclear how fluid migration in cold seeps influence the composition of the seabed microbiome and if they transport deep subsurface life up to the surface. In this study, we addressed this knowledge gap by analyzing over 180 marine surficial sediments from the Gulf of Mexico and the Monterey Bay to assess whether hydrocarbon fluid migration serves as a mechanism for the dispersal of subsurface extremophiles and their introduction into the seabed via cold seeps. Seafloor samples were collected either by piston coring or ROV-operated push coring and were stored at -20°C upon collection. Presence of hydrocarbons in the piston core sediments wa characterized by gas chromatography mass spectrometry and fluorescence spectroscopy whereas gas seepage was determined in the ROV push cores by visual confirmation of gas bubbles emanating from the seafloor. Sediment microbiome composition was determined by high throughput 16S rRNA gene amplicon sequencing. Metabolic diversity was assessed via a genome-centric metagenomics approach aided by shotgun metagenomic sequencing of selected samples. Additionally, viable bacterial endospore communities were investigated from a subset of over 120 of the above samples by allowing endospore germination using a high-temperature incubation assay followed by amplicon sequencing. While 132 of the piston core sediments contained migrated liquid hydrocarbons, evidence of continuous advective transport of thermogenic alkane gases was observed in 11 sediments. Gas seeps harbored distinct microbial communities featuring bacteria and archaea that are well known inhabitants of deep biosphere sediments. Specifically, 25 distinct sequence variants within the bacterial lineages Atribacterota and Aminicenantia and the archaeal lineage Thermoprofundales occurred in significantly greater relative sequence abundance along with well-known seep-colonizing members of the bacterial genus Sulfurovum, in the gas-positive sediments. Metabolic predictions guided by metagenome-assembled genomes suggested these organisms are anaerobic heterotrophs capable of non-respiratory breakdown of organic matter, likely enabling them to inhabit energy-limited deep subseafloor ecosystems. In addition, eight different lineages of anaerobic bacterial endospores activated by sediment incubation assays were strongly associated with hydrocarbon-bearing sediments. These lineages were most closely related to Clostridiales previously detected in oil reservoirs from around the world. These results cumulatively point to petroleum geofluids as a vector for the advection-assisted upward dispersal of deep biosphere microbes from subsurface to surface environments, shaping the microbiome of cold seep sediments and providing a general mechanism for the maintenance of microbial diversity in the deep sea.

Shock Synthesis of Organic Molecules by Meteoroids in the Atmosphere of Titan

Thermochemical modeling and shock-tube experiments show that shocks applied to N2/CH4 gas mixtures can synthesize organic molecules. Sufficiently large, hypersonic meteoroids entering the atmosphere of Saturn’s moon Titan should therefore drive organic chemistry. To do so meteoroids must be sufficiently large compared to the atmospheric mean free path at a given altitude to generate shocks, and deposit enough energy per path length to produce temperatures high enough to excite and dissociate the relevant molecules. The Cassini spacecraft imaged multiple meteoroid impacts on Saturn’s rings, allowing for the first time an empirical estimate to be made of the flux and size–frequency distributions of meteoroids in the millimeter-to-meter size range. We combine these results with an atmospheric entry model and thermochemical and experimental shock production efficiencies for N2/CH4 atmospheres and calculate the shock production rates for HCN, C2H2, and C2H4 as well as the resulting H2 generation. We find that meteoroids may be producing these molecules at as much as ∼1% the production rate of photochemistry driven by UV photons, and may be depositing more energy than magnetospheric ions and 90–100 nm UV photons. Moreover, these meteoroids produce these organic molecules hundreds of kilometers lower in Titan’s atmosphere than the relevant UV photons and magnetospheric ions penetrate, with peak production occurring between 200 and 500 km altitudes, i.e., at the observed haze layer. Meteoroid-driven shock generation of molecules may therefore be crucial to understanding Titan’s atmospheric chemistry.

Prędkości kosmiczne

Movement in nature is ubiquitous. Everything around us moves, from electrons and protons to stars and galaxies. By definition, velocity is the distance traveled by a given object (human, plane, elementary particle,...) in a time unit. And velocity seems to be more and more important in a quick-changing world. Velocity in the universe is crucial because it is related to the trajectory of movement and the possibility of achieving a given goal.When determining velocity, we always define a reference point.This paper explores the “cosmic” relativity of velocity and how it affects humanity’s space missions. Undoubtedly we are becoming “space wanderers”, for whom reaching further space goals has become the essence of life. Jupiter’s moons, Saturn’s moon Titan are our next long-term goals, but there is speed in the way of achieving these goals in a reasonable time for human. In order to achieve further ambitious goals, we need to increase the available travel velocity

Rapid Aggregation and Dissolution of Organic Aerosols in Liquid Methane on Titan

AbstractComplex organic aerosols in the upper atmosphere of Saturn's moon Titan reach the troposphere and surface, where a methane (CH4)‐based hydrological cycle occur. Previous studies have assumed no interactions between organic aerosols and liquid CH4, although the dissolution of low‐molecular‐weight photochemical products in liquid CH4 has been considered. Here we report experimental results of soaking a laboratory analog (so‐called tholin) of Titan's organic aerosols in liquid CH4 at 93–98 K for several hours and then evaporating the liquid, simulating wet–dry cycling on Titan. After wet–dry cycling, residual tholin particles form aggregates through cementation. Solid evaporitic deposits formed by evaporation of interacted liquid contain nitrogen‐bearing aromatics, suggesting selective dissolution of aromatics. Our results suggest that organic aerosols or high‐molecular‐weight compounds adsorbed on them partly dissolve in liquid CH4 on Titan, even during short‐term wetting events, promoting the growth of aerosols to dune particles via aggregation and providing aromatics to evaporites.

Crossroads at the Origin of Prebiotic Chemical Complexity: Hydrogen Cyanide Product Diversification.

Products of hydrogen cyanide (HCN) reactivity are suspected to play important roles in astrochemistry and, possibly, the origin of life. The composition, chemical structure, and mechanistic details for formation of products from HCN's self-reactions have, however, proven elusive for decades. Here, we elucidate base-catalyzed reaction mechanisms for the formation of diaminomaleonitrile and polyimine in liquid HCN using ab initio molecular dynamics simulations. Both materials are proposed as key intermediates for driving further chemical evolution. The formation of these materials is predicted to proceed at similar rates, thereby offering an explanation of how HCN's self-reactions can diversify quickly under kinetic control. Knowledge of these reaction routes provides a basis for rationalizing subsequent reactivity in astrochemical environments such as on Saturn's moon Titan, in the subsurface of comets, in exoplanet atmospheres, and on the early Earth.

Molecular Structure, Dynamics, and Vibrational Spectroscopy of the Acetylene:Ammonia (1:1) Plastic Co-Crystal at Titan Conditions

The Saturnian moon Titan has a thick, organic-rich atmosphere, and condensed phases of small organic molecules are anticipated to be stable on its surface. Of particular importance are crystalline phases of organics, known as cryominerals, which can play important roles in surface chemistry and geological processes on Titan. Many of these cryominerals could exhibit rich phase behavior, especially multicomponent cryominerals whose component molecules have multiple solid phases. One such cryomineral is the acetylene:ammonia (1:1) co-crystal, and here we use density functional theory-based ab initio molecular dynamics simulations to quantify its structure and dynamics at Titan conditions. We show that the acetylene:ammonia (1:1) co-crystal is a plastic co-crystal (or rotator phase) at Titan conditions because the ammonia molecules are orientationally disordered. Moreover, the ammonia molecules within this co-crystal rotate on picosecond time scales, and this rotation is accompanied by the breakage and reformation of hydrogen bonds between the ammonia hydrogens and the π-system of acetylene. The robustness of our predictions is supported by comparing the predictions of two density functional approximations at different levels of theory, as well as through the prediction of infrared and Raman spectra that agree well with experimental measurements. We anticipate that these results will aid in understanding geochemistry on the surface of Titan.

Deformation characteristics of solid-state benzene as a step towards understanding planetary geology

Small organic molecules, like ethane and benzene, are ubiquitous in the atmosphere and surface of Saturn’s largest moon Titan, forming plains, dunes, canyons, and other surface features. Understanding Titan’s dynamic geology and designing future landing missions requires sufficient knowledge of the mechanical characteristics of these solid-state organic minerals, which is currently lacking. To understand the deformation and mechanical properties of a representative solid organic material at space-relevant temperatures, we freeze liquid micro-droplets of benzene to form ~10 μm-tall single-crystalline pyramids and uniaxially compress them in situ. These micromechanical experiments reveal contact pressures decaying from ~2 to ~0.5 GPa after ~1 μm-reduction in pyramid height. The deformation occurs via a series of stochastic (~5-30 nm) displacement bursts, corresponding to densification and stiffening of the compressed material during cyclic loading to progressively higher loads. Molecular dynamics simulations reveal predominantly plastic deformation and densified region formation by the re-orientation and interplanar shear of benzene rings, providing a two-step stiffening mechanism. This work demonstrates the feasibility of in-situ cryogenic nanomechanical characterization of solid organics as a pathway to gain insights into the geophysics of planetary bodies.

Life on Titan May Signal Early Life in the Universe

The temperature of the cosmic microwave background was equal to the surface temperature of Saturn’s moon Titan, 94 K, at a redshift z = 33.5, after the first galaxies formed. Titan-like objects would have maintained this surface temperature for tens of Myr irrespective of their distance from a star. Titan has the potential for the chemistry of familiar life in its subsurface water ocean, as well new forms of life in the rivers, lakes and seas of liquid methane and ethane on its surface. The potential future discovery of life on Titan would open the possibility that the earliest lifeforms emerged in metal-rich environments of the earliest galaxies in the universe, merely 100 Myr after the big bang.

Potential Caves: Inventory of Subsurface Access Points on the Surface of Titan

AbstractWe propose that cycling hydrocarbon rains on Saturn's moon Titan are likely to create subsurface conduits through dissolution geology of the extensive organic and largely‐soluble substrate. In this work we inventory different terrains and locations on Titan that could host potential subsurface access points or caves. Using Cassini data, we identified and enumerated a cryovolcanic construct, filled and empty lake basins that may have formed through karstic processes, estimates of closed valleys in organic plateaux, and enigmatic equatorial pits. Our preliminary survey identified over 21,000 estimated locations for future exploration to identify potential caves and cave forming processes on that world. We speculate that the exploration of these caves could teach us about the cave forming processes, as well as the past climate history and perhaps even chemical deposition history on Titan.