{"title":"Radiation-induced reactions in comet analogues","authors":"A. López-Islas, A. Negrón-Mendoza","doi":"10.1017/s1473550422000416","DOIUrl":"https://doi.org/10.1017/s1473550422000416","url":null,"abstract":"\u0000 Comets are a source of prebiotic molecules that likely enriched the early Earth during the Late Heavy Bombardment period. Laboratory experiments that replicate cometary conditions may facilitate understanding of the chemical reactions and supplement observational studies of these icy bodies. Prebiotic compounds, such as formic acid and formaldehyde, have been observed in comets. Furthermore, these compounds can easily be formed in experimental models using a variety of gas combinations and energy sources. We conducted experimental cometary simulations using radiation chemistry tools to obtain insight into the possible fate of formic acid and formaldehyde. The main results suggest a redundant system, signifying that the irradiation of formic acid forms formaldehyde molecules and vice versa. This phenomenon ensures the permanence of prebiotic molecules in high-radiation environments. Additionally, the potential role of forsterite and graphite was explored in cometary simulations. Our experimental results show the differential formation of aldehydes and other carbonyl-containing compounds dependent on the mineral phase present.","PeriodicalId":13879,"journal":{"name":"International Journal of Astrobiology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46384142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Extraterrestrial nature reserves (ETNRs)","authors":"Paul L. Smith","doi":"10.1017/s1473550422000398","DOIUrl":"https://doi.org/10.1017/s1473550422000398","url":null,"abstract":"\u0000 If human population growth is not controlled, natural areas must be sacrificed. An alternative is to create more habitat, terraforming Mars. However, this requires establishment of essential, ecosystem services on a planet currently unamenable to Terran species. Shorter term, assembling Terran-type ecosystems within contained environments is conceivable if mutually supportive species complements are determined. Accepting this, an assemblage of organisms that might form an early, forest environment is proposed, with rationale for its selection. A case is made for developing a contained facsimile, old growth forest on Mars, providing an oasis, proffering vital ecosystem functions (a forest bubble). It would serve as an extraterrestrial nature reserve (ETNR), psychological refuge and utilitarian botanic garden, supporting species of value to colonists for secondary metabolites (vitamins, flavours, perfumes, medicines, colours and mood enhancers). The design presented includes organisms that might tolerate local environmental variance and be assembled into a novel, bioregenerative forest ecosystem. This would differ from Earthly forests due to potential impact of local abiotic parameters on ecosystem functions, but it is argued that biotic support for space travel and colonization requires such developments. Consideration of the necessary species complement of an ETNR supports a view that it is not humanity alone that is reaching out to space, it is life, with all its diverse capabilities for colonization and establishment. Humans cannot, and will not, explore space alone because they did not evolve in isolation, being shaped over aeons by other species. Space will be travelled by a mutually supportive system of Terran organisms amongst which humans fit, exchanging metabolites and products of photosynthesis as they have always done.","PeriodicalId":13879,"journal":{"name":"International Journal of Astrobiology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45030744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Brief review about history of astrobiology","authors":"B. Nascimento-Dias, J. Martínez-Frías","doi":"10.1017/s1473550422000386","DOIUrl":"https://doi.org/10.1017/s1473550422000386","url":null,"abstract":"\u0000 The main idea of this work is to develop a chronological and descriptive historical review in a summarized form about content on astrobiology, which is a research area considered as an emerging science. This is exploratory research that was developed from document review from scientific articles and books, that related to the themes of astrobiology, exobiology and the search for life outside the Earth were used. Based on the research developed, it was possible to collect data related to the vision of other worlds beyond Earth from the ancient Greeks to the present day. Finally, it was possible to conclude that although astrobiology is a recent area of scientific research, the concept and search for life outside the Earth already existed long before the development of modern science.","PeriodicalId":13879,"journal":{"name":"International Journal of Astrobiology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44402721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Formalizing the Fermi paradox and combining consistent explanatory hypotheses","authors":"Alexandre Costa-Leite","doi":"10.1017/s1473550422000374","DOIUrl":"https://doi.org/10.1017/s1473550422000374","url":null,"abstract":"\u0000 A formalization of Fermi paradox inside the environment of classical propositional logic is proposed. The notion of Silentium Universi set is launched in order to establish that the Fermi paradox is truly paradoxical. Combining consistent explanatory hypotheses is taken into consideration and discussed inside this framework explaining what would count as a solution to the paradox. By the end, it is argued that Fermi paradox is an unsolvable problem in the domain of science.","PeriodicalId":13879,"journal":{"name":"International Journal of Astrobiology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44428650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Solid grains ejected from terrestrial exoplanets as a probe of the abundance of life in the Milky Way","authors":"T. Totani","doi":"10.1017/S147355042300006X","DOIUrl":"https://doi.org/10.1017/S147355042300006X","url":null,"abstract":"\u0000 Searching for extrasolar biosignatures is important to understand life on Earth and its origin. Astronomical observations of exoplanets may find such signatures, but it is difficult and may be impossible to claim unambiguous detection of life by remote sensing of exoplanet atmospheres. Here, another approach is considered: collecting grains ejected by asteroid impacts from exoplanets in the Milky Way and then travelling to the Solar System. The optimal grain size for this purpose is around 1 μm, and though uncertainty is large, about 105 such grains are expected to be accreting on Earth every year, which may contain biosignatures of life that existed on their home planets. These grains may be collected by detectors placed in space, or extracted from Antarctic ice or deep-sea sediments, depending on future technological developments.","PeriodicalId":13879,"journal":{"name":"International Journal of Astrobiology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41457089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Cavalazzi, F. Westall, L. Noack, R. Taubner, T. Milojevic, K. Finster
{"title":"Special issue: Open questions and next steps in astrobiology in Europe – celebrating 20 years of EANA","authors":"B. Cavalazzi, F. Westall, L. Noack, R. Taubner, T. Milojevic, K. Finster","doi":"10.1017/S1473550422000362","DOIUrl":"https://doi.org/10.1017/S1473550422000362","url":null,"abstract":"(origin and evolution of planetary systems; origins of organic compounds in space; rock – water – carbon interactions, as on the surface of Mars and of about 13 million years at 2 metres depth. In addition, they highlight that chitin may also be included in the list of robust biosignature molecules for which one could search for during life-seeking missions.","PeriodicalId":13879,"journal":{"name":"International Journal of Astrobiology","volume":"21 1","pages":"261 - 267"},"PeriodicalIF":1.7,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45257619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Microbial protocols for spacecraft: 2. Biocidal effects of Delrin and nylon in sealed compartments may enhance bioburden reductions in planetary spacecraft","authors":"A. Schuerger, P. Schwendner, R. Tucker","doi":"10.1017/s1473550422000349","DOIUrl":"https://doi.org/10.1017/s1473550422000349","url":null,"abstract":"\u0000 Interplanetary spacecraft are assembled with thousands of parts composed of many diverse materials. Little is known on whether any of the spacecraft materials are biocidal to the typical microbiomes that develop on spacecraft during pre-launch processing. During ongoing experiments to examine the interactive effects of solar UV irradiation, solar heating, ionizing radiation, and vacuum, we observed that bacterial spores of three Bacillus spp. were killed when incubated within small vacuum chambers for 5 days – without exposure to the aforementioned factors. Eight potential spacecraft materials were tested within the vacuum chambers for biocidal activities against spores of B. atrophaeus ATCC 9372, B. pumilus SAFR-032 and B. subtilis 168. All three species were fully inactivated (i.e., no survivors detected) by machined parts manufactured from Delrin®; a thermoplastic polyacetal polymer. Although not tested here, it is known that Delrin can off-gas formaldehyde, and thus, we hypothesize that this volatile organic compound (VOC) was responsible for the biocidal activity of the material. Knowledge of the biocidal nature of routinely used spacecraft materials might offer diverse methods to inactivate deeply embedded or shielded microbiota within spacecraft via the release of biocidal VOCs.","PeriodicalId":13879,"journal":{"name":"International Journal of Astrobiology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42578742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Abiogenesis: the Carter argument reconsidered","authors":"D. Whitmire","doi":"10.1017/s1473550422000350","DOIUrl":"https://doi.org/10.1017/s1473550422000350","url":null,"abstract":"\u0000 The observation of life on Earth is commonly believed to be uninformative regarding the probability of abiogenesis on other Earth-like planets. This belief is based on the selection effect of our existence. We necessarily had to find ourselves on a planet where abiogenesis occurred, thus nothing can be inferred about the probability of abiogenesis from this observation alone. This argument was first formalized in a Bayesian framework by Brandon Carter. Though we definitely had to find ourselves on a planet where abiogenesis occurred, I argue here that (1) the Carter conclusion is based on what is known as the ‘Old Evidence Problem’ in Bayesian Confirmation Theory and that (2) taking this into account, the observation of life on Earth is not neutral but evidence that abiogenesis on Earth-like planets is relatively easy. I then give an independent timescale argument that quantifies the prior probabilities, leading to the inference that the timescale for abiogenesis is less than the planetary habitability timescale and therefore the occurrence of abiogenesis on Earth-like planets is not rare.","PeriodicalId":13879,"journal":{"name":"International Journal of Astrobiology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44703893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Stromatolite photomorphogenesis: lighting up their shape","authors":"G. Ojakangas, S. Awramik, M. Storrie-Lombardi","doi":"10.1017/s1473550422000313","DOIUrl":"https://doi.org/10.1017/s1473550422000313","url":null,"abstract":"\u0000 Most stromatolites are built by photosynthetic organisms, for which sunlight is a driving factor. We examine stromatolite morphogenesis with modelling that incorporates the growth rate of cyanobacteria (the dominant stromatolite-builder today, and presumably through much of the past), as a function of the amount of irradiance received. This function is known to be non-monotonic, with a maximum beyond which growth rate decreases. We define optimal irradiance as that which generates maximal growth, and we find fundamentally different morphologies are predicted under suboptimal and superoptimal direct irradiance. When the direct irradiance is suboptimal, narrow widely spaced columns are predicted, with sharp apices resembling conical stromatolites. When it is superoptimal, broad, closely spaced, flattened domical forms appear. Such disparate morphologies could also occur as a result of other vector-flux-dependent growth factors (e.g. currents). A differential equation is developed that describes the rate of change of the radius of curvature R at the apex of a growing stromatolite column, allowing simple simulations of the time evolution of R for model stromatolites. The term photomorphism is proposed to describe the disparate morphologies that may arise due to the effects described here (and photomorphogenesis as the process). Model results appear to explain, at least qualitatively, the morphologies of a number of stromatolites. If stromatolites are encountered on Mars, our model suggests that they are quite likely to be conical in form, owing to likely suboptimal irradiance since Mars has always received less irradiance than Earth.","PeriodicalId":13879,"journal":{"name":"International Journal of Astrobiology","volume":"15 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41310564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Extraterrestrial intelligence and moral standing","authors":"M. Ćirković, Ana Katić","doi":"10.1017/s1473550422000337","DOIUrl":"https://doi.org/10.1017/s1473550422000337","url":null,"abstract":"\u0000 We consider the Search for ExtraTerrestrial Intelligence (SETI) activities from a bioethical standpoint. In particular, we argue that there is a moral duty to search for other intelligent beings in the Universe. Some of them could – and are likely to be – morally enhanced in the sense that they are not only capable of unmistakable moral reasoning but are also capable of consistently acting upon the results of such deliberations. Even if the probability of finding such morally superior beings is small, it is higher than zero in any case; in fact, our astrobiological knowledge suggests that this probability is significant. Hence, there are both deductive and inductive arguments for the proposition that our duty is to search for such morally superior extraterrestrial beings. In other words, there is a duty to undertake and support our SETI efforts. The argument to that effect runs parallel to some of the arguments deployed in current debates on human moral enhancement.","PeriodicalId":13879,"journal":{"name":"International Journal of Astrobiology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42838890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}