We quantitatively studied the hydration and dehydration behaviour of the three astrobiological model lichens Xanthoria elegans, Buellia frigida and Circinaria gyrosa by thermoanalysis and gravimetric isotherm measurements under close-to-Martian environmental conditions in terms of low temperature and low pressure. Additionally, the impact of UVC exposure on the isolated symbionts of B. frigida and X. elegans was studied by thermoanalysis and mass spectrometry as well as by gravimetric isotherm measurements. The thermal analysis revealed whewellite as a component of C. gyrosa which was not found in B. frigida and X. elegans. Neither the water retention nor the thermal behaviour of symbionts changed when irradiated with UVC under dry conditions. On the other hand, UVC irradiation of the wet mycobiont of B. frigida had a distinct impact on the hydration/dehydration ability which was not observed for the mycobiont of X. elegans. Possibly the melanin of B. frigida's mycobiont, that is not present in X. elegans, or a specifically damaged acetamido group of the chitin of B. frigida may be the sources of additional UVC-induced sorption sites for water associated with the UVC exposure.

Collisions amongst comets create belts of orbiting debris and, by using submillimetre wavelength observations, these collision zones can be imaged around nearby stars. An image of the closest Solar analogue, τ Ceti, shows that it possesses at least 20 times the content of the outer Solar System in cool debris particles. The inferred population of parent colliders is around 1 M[oplus ], also much larger than in the Sun's Kuiper Belt of comets. This system represents a different evolutionary outcome for a Sun-like star, with no Jupiter-like planet but many cometary bodies, and thus a potentially heavy and prolonged history of impacts on any inner terrestrial planets. Since τ Ceti is 10 Gyr old, life would have had to deal with massive bombardment over very long timescales. Furthermore, impactors in the 10 km-upwards class could arrive at intervals of 1 Myr or less, longer than recovery times on Earth, and so similar biology is unlikely. It is presently unknown whether nearby stars typically have comet belts similar to that of the Sun or of τ Ceti; extrapolations of existing data suggest many stars could be at least 2–5 times above the Solar debris level. Future large telescopes will be able to probe down to Solar System levels of cometary debris.

New findings pertinent to the human lineage origin (Ardipithecus ramidus) prompt a new analysis of the extrapolation of the social behavior of our closest relatives, the great apes, into human ‘natural social behavior’. With the new findings it becomes clear that human ancestors had very divergent social arrangements from the ones we observe today in our closest genetic relatives.

The social structure of chimpanzees and gorillas is characterized by male competition. Aggression and the instigation of fear are common place. The morphology of A. ramidus points in the direction of a social system characterized by female-choice instead of male–male competition. This system tends to be characterized by reduced aggression levels, leading to more stable arrangements. It is postulated here that the social stability with accompanying group cohesion propitiated by this setting is favorable to the investment in more complex behaviors, the development of innovative approaches to solve familiar problems, an increase in exploratory behavior, and eventually higher intelligence and the use of sophisticated tools and technology.

The concentration of research efforts into the study of social animals with similar social systems (e.g., New World social monkeys (Callitrichidae), social canids (Canidae) and social rodents (Rodentia)) are likely to provide new insights into the understanding of what factors determined our evolution into an intelligent species capable of advanced technology.

The Solar System passes within 5 pc of star-forming nebulae every ∼50–100 million years, a distance which can be bridged by protected micro-organisms ejected from the Earth by impacts. Such encounters disturb the Oort cloud, and induce episodes of bombardment of the Earth and the ejection of microbiota from its surface. Star-forming regions within the nebulae encountered may thus be seeded by significant numbers of microorganisms. Propagation of life throughout the Galactic habitable zone ‘goes critical’ provided that, in a typical molecular cloud, there are at least 1.1 habitable planets with impact environments similar to that of the Earth. Dissemination of microbiota proceeds most rapidly through the molecular ring of the Galaxy.

Astrobiology's goal of promoting interdisciplinary research is an attempt to reverse a trend that began two centuries ago with the formation of the first specialized scientific disciplines. We have examined this era of discipline formation in order to make a comparison with the situation today in astrobiology. Will astrobiology remain interdisciplinary or is it becoming yet another specialty?

As a case study, we have investigated effects on the scientific literature when a specialized community is formed by analyzing the citations within papers published during 1802–1856 in Philosophical Transactions of the Royal Society (Phil. Trans.), the most important ‘generalist’ journal of its day, and Transactions of the Geological Society of London (Trans. Geol. Soc.), the first important disciplinary journal in the sciences. We find that these two journals rarely cited each other, and papers published in Trans. Geol. Soc. cited fewer interdisciplinary sources than did geology papers in Phil. Trans. After geology had become established as a successful specialized discipline, geologists returned to publishing papers in Phil. Trans., but they wrote in the new, highly specialized style developed in Trans. Geol. Soc. They had succeeded in not only creating a new scientific discipline, but also a new way of doing science with its own modes of research and communication.

A similar citation analysis was applied to papers published over the period 2001–2008 in the contemporary journals Astrobiology and the International Journal of Astrobiology to test the hypothesis that astrobiologists are in the early stages of creating their own specialized community. Although still too early to reliably detect any but the largest trends, there is no evidence yet that astrobiologists are drifting into their own isolated discipline. Instead, to date they appear to remain interdisciplinary.

Astronomical observations of Centaurs and trans-Neptunian objects (TNOs) yield two characteristic features – near-infrared (NIR) reflectance and low geometric albedo. The first feature apparently originates due to complex organic material on their surfaces, but the origin of the material contributing to low albedo is not well understood. Titan tholins synthesized to simulate aerosols in the atmosphere of Saturn's moon Titan have also been used for simulating the NIR reflectances of several Centaurs and TNOs. Here, we report novel detections of large polycyclic aromatic hydrocarbons, nanoscopic soot aggregates and cauliflower-like graphite within Titan tholins. We put forth a proof of concept stating the surfaces of Centaurs and TNOs may perhaps comprise of highly ‘carbonized’ complex organic material, analogous to the tholins we investigated. Such material would apparently be capable of contributing to the NIR reflectances and to the low geometric albedos simultaneously.

Goal 7 of the NASA Astrobiology Roadmap states: ‘Determine how to recognize signatures of life on other worlds and on early Earth. Identify biosignatures that can reveal and characterize past or present life in ancient samples from Earth, extraterrestrial samples measured in situ, samples returned to Earth, remotely measured planetary atmospheres and surfaces, and other cosmic phenomena.’ The cryptic reference to ‘other cosmic phenomena’ would appear to be broad enough to include the possible identification of biosignatures embedded in the dimensionless constants of physics. The existence of such a set of biosignatures – a life-friendly suite of physical constants – is a retrodiction of the Selfish Biocosm (SB) hypothesis. This hypothesis offers an alternative to the weak anthropic explanation of our indisputably life-friendly cosmos favoured by (1) an emerging alliance of M-theory-inspired cosmologists and advocates of eternal inflation like Linde and Weinberg, and (2) supporters of the quantum theory-inspired sum-over-histories cosmological model offered by Hartle and Hawking. According to the SB hypothesis, the laws and constants of physics function as the cosmic equivalent of DNA, guiding a cosmologically extended evolutionary process and providing a blueprint for the replication of new life-friendly progeny universes.

Creating a unified model of life in the universe – history, extent and future – requires both scientific and humanities research. One way that humanities can contribute is by investigating the relationship between philosophical commitments and data. Making those commitments transparent allows scientists to use the data more fully. Insights in four areas – history, ethics, religion and probability – demonstrate the value of careful, astrobiology-specific humanities research for improving how we talk and think about astrobiology as a whole. First, astrobiology has a long and influential history. Second, astrobiology does not decentre humanity, either physically or ethically. Third, astrobiology is broadly compatible with major world religions. Finally, claims about the probability of life arising or existing elsewhere rest heavily on philosophical priors. In all four cases, identifying philosophical commitments clarifies the ways in which data can tell us about life.

Laser-ablation inductively coupled plasma mass spectroscopy analyses have been performed on carbonaceous filamentous structures that have been interpreted as fossilized microorganisms containing ~10–50 wt% Fe and on non-carbonaceous filamentous structures that have been interpreted to have been formed abiotically containing ~80 wt% Fe. The obtained laser-ablation profiles of the two structural types show a distinct difference in the iron isotopic variations. The centers of the carbonaceous filaments are enriched in 57Fe and 58Fe and depleted in 56Fe. The surficial parts of the filaments display an opposite behavior of the iron isotopes and are thus enriched in 56Fe and depleted in 57Fe and 58Fe. 54Fe usually follows 57Fe and 58Fe but in some cases it follows 56Fe instead. The outer, surficial parts enriched in 56Fe have been interpreted as iron oxides precipitated on the surfaces of the microorganisms as they mediate oxidation of the iron to achieve metabolic energy. The laser-ablation profiles of the abiotically formed non-carbonaceous filamentous structures do not show the same characteristics as the carbonaceous filaments but only irregular elevations of 56Fe. The characteristic profile patterns of the isotope variations in the microfossils suggest that microbially formed iron oxides may be enriched in 56Fe. If that is the case the isotopic profiles could be used to distinguish abiotically formed iron oxides from biologically formed oxides.

I argue that the attempts of astrobiologists and philosophers to provide an ethical justification for planetary protection policies (in particular, those aspects of policy concerning forward contamination) suffer from a ‘life bias’ in that reasons for protection are regarded as genuinely ethical only when they include some kind of direct moral consideration for extraterrestrial life. There are, I maintain, good reasons for the protection of space environments, including the protection of sites of interest to disciplines other than astrobiology. These reasons are no less ethical simply because their aim is something other than the protection of extraterrestrial life. While the possible existence of such reasons has been recognized, they have yet to be developed in a philosophically satisfying way. This paper aims to fill this lacuna by motivating and articulating an ethical perspective which recommends broader protection of the space environment. Long-range implications for such a broadening of planetary protection are considered, including implications for interstellar exploration.

We live in a scientific world; paradoxically, the scientific literacy of the population is minimal at best. Science is an ongoing process, a human endeavour; paradoxically, students tend to believe that science is a finished enterprise. Many non-science major students are not motivated in science classes; paradoxically, there is a public fascination with the possibility of life in the Universe, which is nowadays a scientific endeavour. An astrobiology course was developed at the Center for Science and Mathematics Education at The University of Texas at Austin to address these paradoxes and includes the following objectives: (a) to improve scientific literacy; (b) to demonstrate that science is a work in progress; (c) to enhance the inherent interdisciplinary aspect of science; (d) to demonstrate that science is embedded in society and relates with several social sciences; (e) to improve the content knowledge about the nature of science; (f) to illustrate how engaging learning science can be; and (g) to draw from the intrinsic motivation already incorporated in the general population. The course has been offered, taught and revised for the past three years. The informal course student feedback has been very positive and encouraging. The purpose of this paper is to provide a general overview of the course. In addition, the course's background, content, themes and mode of delivery are outlined, discussed and analysed in this paper. This paper subscribes to an educational philosophy that focuses on the multidisciplinary nature of science and includes critical thinking-based teaching strategies using the dynamic discipline of astrobiology.

A new concept is proposed, according to which the plasma and collision processes accompanying hypervelocity impacts of meteorites can contribute to the arising of the conditions on early Earth, which are necessary for the appearance of primary forms of living matter. It was shown that the processes necessary for the emergence of living matter could have started in a plasma torch of meteorite impact and have continued in an impact crater in the case of the arising of the simplest life form.

It is generally accepted that planets are the optimal place for the origin and evolution of life. In the process of forming the planetary systems the meteorites, space bodies feeding planet growth, appear around stars. In the process of Earth's formation, meteorite sizes ranged from hundreds and thousands of kilometres. These space bodies consisted mostly of the planetesimals and comet nucleus. During acceleration in Earth's gravitational field they reached hypervelocity and, hitting the surface of planet, generated powerful blowouts of hot plasma in the form of a torch. They also created giant-size craters and dense dust clouds. These bodies were composed of all elements needed for the synthesis of organic compounds, with the content of carbon being up to 5%–15%.

A new idea of possible synthesis of the complex organic compounds in the hypervelocity impact-generated plasma torch was proposed and experimentally confirmed. A previously unknown and experimentally corroborated feature of the impact-generated plasma torch allowed a new concept of the prehistory of life to be developed. According to this concept the intensive synthesis of complex organic compounds arose during meteoritic bombardment in the first 0.5 billion years at the stage of the planet's formation. This most powerful and destructive action in Earth's history could have played a key role and prepared conditions for the origin of life.

In the interstellar gas–dust clouds, the synthesis of simple organic matter could have been explained by an identical process occurring in the plasma torch of hypervelocity collisions between submicron size dust particles. It is assumed that the processes occurred in the highly unbalanced hot plasma simultaneously with the synthesis of simple and complicated organic compounds, thereby ensuring their ordering and assembly.

Bona fide experimental evidence presented below indicates that the physical fields generated in the plasma environment in the process of the formation and expansion of the torch meet the main requirements toward “true” local chiral fields. These fields were very likely to be capable to trigger the initial, weak breaking of enantiomer symmetry and determine the “sign” of the asymmetry of the bioorganic world.

These fields could have worked as “trapping” fields influencing spontaneous processes occurring in highly overheated and nonequilibrium plasma in the state that is far from the thermodynamical branch of equilibrium and may have contributed to the formation of an environment needed for the synthesis of homochiral molecular structures, which, in turn, were needed for the emergence of the primary forms of living matter.

It has been shown experimentally that the plasma-chemical processes in the torch have high catalytic properties and assure the rise of the chemical reaction rates by 10–100 million times. In the process of the plasma flyaway this in turn can assure the fast formation of simple and complicated organic compounds, including hyper-branched polymers. It is possible to assume that predominantly inorganic substances from meteorites were used for the synthesis of complicated organic compounds on early Earth.

A laboratory experiment with hypervelocity impact plasma torch modelling by a laser with a Q-switch mode has shown the possibility of high-molecular organic compound synthesis, with mass of approximately 5000 a.m.u. by meteorite impact with an effective diameter of 100 mkm. The target contained only H, C, N and O elements in inorganic forms. The approximation of the curve received in these experiments has shown that molecular structures comparable in mass with the protoviroid (a hypothetical primogenitor of the biosphere) and could have been synthesized as a result of the impact of a meteorite of a millimetre-size range.

Observable characteristics of the synthesis processes suggest high catalytic activity of the plasma medium and high speed of plasma-chemical reactions, combined with ordering and assemblage processes. This suggests that the plasma torch with a huge local density of energy and matter may be the optimal medium for the synthesis of complex organic compounds needed for prebiotic evolution and the development of the primary form of living matter.

A new view of the impact crater provides the most interesting and unexpected consequence of the concept proposed. When considering the problem, it became evident that at a prebiotic stage of evolution there should be an environment in which a photogenic creature could have survived. The crater of the meteoric impact, which is capable of producing ‘a primogenitor of the biosphere’ environment sated with organic matter, moderate temperature and water for considerable time and becoming ‘a life cradle’, appears to be such an environment.

Having enormous energy, the meteorite impact is capable of injecting the newly created complicated organic compounds deep into the space body surfaces, including subsurface water reservoirs, such as Europe, Enchilada and Titan. In this case the meteorite impact has no natural alternative in the creation of initial conditions for the origin of extraterrestrial life. This possibility was confirmed by a laboratory impact model experiment, in which the plasma torch was created under the water surface.

The concept proposed is based on physical processes occurring in nature and on experimental results of impact experiments and subsequent modelling of their analogues in laboratory conditions. Thus, the realizability and survivability of this concept should be taken as well grounded due to the simplicity and clarity of the physical processes.

In Mars-analogous hyperarid soils of the Atacama Desert, phospholipid fatty acids (PLFAs) as the main component of biomembrane play a role in reliably determining viable microbes. PLFA analyses illustrated a rise of the microbial abundance (from 5.0 × 106 to 4.2 × 107 cells g−1) and biodiversity (from 7 to 15 different individual PLFAs) from the north hyperarid core of the Atacama Desert to the southern arid region. Abundant cyclopropyl PLFAs (47.2 ± 4.6%) suggested the resistance to oligotrophic and hypersaline environments by Atacama microbial communities. The southernmost arid site had the highest proportion (8.7%) of eukaryotic and fungal lipid biomarkers. Different precipitations (ranging from 0.7 to 2 mm year−1) in the hyperarid core exerted different effects on microbial biomass, PLFA diversity, bacteria and microeukaryotes. By principal component analysis (cumulative 74.6% of variance), the dominance of PLFA hydroxylation was associated with the microbial viability; bacteria rich in C16:0, C18:0 and C16:1ω9 favoured higher soil conductivity and nitrate; and other PLFAs contributed more to the organic content. Additionally by comparing the ratios of PLFAs to well-preserved organics (e.g., mineral-bound organic carbon and microbial phosphorus), I found that the degradation of PLFAs decreased to a minimum when the mean annual precipitation is lower than 2 mm. These findings may further specify identifiable biomarkers on Mars, if potentially extant Martian microbes possess comparable phospholipid membrane structure.

A high research priority in astrobiology is the search and eventual identification of biomarkers in the Solar System. In spite of numerous steps forward, lunar science remains largely disjoint from the main stream of astrobiology, but in recent years the Moon has begun to emerge as a novel target for astrobiologists. We discuss an overlap between lunar geology and terrestrial geomicrobiology that arises from analysis of lunar soils and some uncertainties in chemical evolution and the origin of life scenarios. Unexpected isotopic heterogeneity of nitrogen (N) was found to be remarkable in samples from Apollo and the Luna programme. Both the stable isotope geochemical data of the biogenic elements, as well as the noble gases trapped in lunar soils added valuable new and relevant data. These discoveries are potential sources of information on early Earth evolution. The elusive ratio of N's two stable isotopes 15N/14N has played a fundamental role in this research. The analysis of individual grains of ilmenite suggests that 90% of all the trapped N does not originate from solar wind (SW). We discuss the significance of these stable isotopes from the point of view of astrobiology in the light of the next generation of lunar exploration. We underline the high priority of testing the origin of non-solar N source trapped in the regolith of the lunar farside. In the proposals of new lunar missions, the characterization of the geochemistry at several lunar sites is a major objective. Some arguments are presented in favour of using novel space technologies in a search for biomarkers in geographical distinct lunar landing sites. We restrict our attention to one aspect of the science requirements for the forthcoming missions by focusing on a very limited objective: to take a closer look at the geochemical characterization of the chemical element N on the soils of the lunar farside.

Astrobiology has been gaining increasing scientific prominence and public attention as the search for life beyond Earth continues to make significant headway on multiple fronts. In view of these recent developments, the fascinating and dynamic etymology of astrobiology is elucidated, and thus shown to encompass a plethora of vivid characters drawn from different continents, religions, ideologies and centuries.

In this paper we consider efficiency of self-reproducing extraterrestrial Von-Neumann micro scale robots and analyse the observational characteristics. By examining the natural scenario of moving in the HII clouds, it has been found that the timescale of replication might be several years and even less – making the process of observation quite promising. We have shown that by encountering the interstellar protons the probes might be visible at least in the infrared energy band and the corresponding luminosities might reach enormous values.

High-temperature submarine hydrothermal fields on Earth's mid-ocean ridges play host to exotic ecosystems with fauna previously unknown to science. Because these systems draw significant energy from chemosynthesis rather than photosynthesis, it has been postulated that the study of such systems could have relevance to the origins of life and, hence, astrobiology. A major flaw to that argument, however, is that modern basalt-hosted submarine vents are too oxidizing and lack the abundant free hydrogen required to drive abiotic organic synthesis and/or the energy yielding reactions that the most primitive anaerobic thermophiles isolated from submarine vent-sites apparently require. Here, however, the progress over the past decade in which systematic search strategies have been used to identify previously overlooked venting on the slow-spreading Mid-Atlantic Ridge and the ultra-slow spreading Arctic and SW Indian Ridges is described. Preliminary identification of fault-controlled venting in a number of these sites has led to the discovery of at least two high-temperature hydrothermal fields hosted in ultramafic rocks which emit complex organic molecules in their greater than 360 °C vent-fluids. Whether these concentrations represent de novo organic synthesis within the hydrothermal cell remains open to debate but it is probable that many more such sites exist throughout the Atlantic, Arctic and SW Indian Oceans. One particularly intriguing example is the Gakkel Ridge, which crosses the floor of the Arctic Ocean. On-going collaborations between oceanographers and astrobiologists are actively seeking to develop a new class of free-swimming autonomous underwater vehicle, equipped with appropriate chemical sensors, to conduct long-range missions that will seek out, locate and investigate new sites of hydrothermal venting at the bottom of this, and other, ice-covered oceans.

Xanthoria parietina is a widespread foliose lichen growing on barks and rocks showing a broad spectrum of tolerance to air pollutants such as NOX and heavy metals, and resistance to UV-radiation because of the screening properties provided by the secondary metabolite parietin. The aim of this study was to evaluate the ability of this lichen species to survive in the following simulated space conditions, UV-radiation in N2 atmosphere and UV-radiation in vacuum. The efficiency of the photosynthetic apparatus was used as an indicator of vitality, and was expressed in terms of chlorophyll a fluorescence (FV/FM) and Normalized Difference Vegetation Index (NDVI), which were measured within 72 h from the exposure. Additionally, during the irradiation, the IR reflectance spectrum of the lichen was monitored in situ to assess changes in spectral bands. The results showed significant differences in physiological recovery trends between the treatments, highlighting that UV-radiation in vacuum causes stronger effects on FV/FM values. The IR analysis revealed several spectral band changes in the fingerprint region. The most visible variation was the 5200 cm−1 water band that disappeared in the overtone region. Nevertheless, X. parietina was able to survive UV-radiation in N2 atmosphere and in vacuum, and for this reason it may be considered a candidate for further evaluations on its survival capacity in extreme conditions.

The current advances in our exploration of Mars have made us think of the human species as a multiplanetary species. However, we have certain challenges before we can truly consider ourselves such a species, especially moral ones. Therefore, astrobioethics would be the right one to examine what it takes to consider ourselves a multiplanetary species. The purpose of this paper is to analyse the meaning and significance of being an inter- and multiplanetary species. To achieve this, a philosophical and critical analysis will be made, using as input aspects of biology, ethics and moral community. We conclude that to be a truly multiplanetary species, more than the technological aspects that allow us to reach other planets, a change at different levels will be needed.