Pub Date : 2021-05-25DOI: 10.1017/S147355042100015X
M. R. Edwards
Assuming that securing the long-term survival of humans and Earth life is a valid goal, we briefly compare the strategies of building standard space colonies, such as on Mars, and embryo space colonization (ESC). In ESC embryos of humans and other Earth species would be sent to exoplanets and raised there via ectogenesis and android assistants. We find that the potential for securing long-term survival is far greater for ESC than for standard colonies, while the bioethical and other risks are far fewer.
{"title":"Space ectogenesis: securing survival of humans and Earth life with minimal risks – reply to Szocik","authors":"M. R. Edwards","doi":"10.1017/S147355042100015X","DOIUrl":"https://doi.org/10.1017/S147355042100015X","url":null,"abstract":"\u0000 Assuming that securing the long-term survival of humans and Earth life is a valid goal, we briefly compare the strategies of building standard space colonies, such as on Mars, and embryo space colonization (ESC). In ESC embryos of humans and other Earth species would be sent to exoplanets and raised there via ectogenesis and android assistants. We find that the potential for securing long-term survival is far greater for ESC than for standard colonies, while the bioethical and other risks are far fewer.","PeriodicalId":13879,"journal":{"name":"International Journal of Astrobiology","volume":"1 1","pages":"1-4"},"PeriodicalIF":1.7,"publicationDate":"2021-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S147355042100015X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45049195","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}
Pub Date : 2021-04-27DOI: 10.1017/S1473550421000082
D. Stevenson
Plate tectonics drives variation in sea-level, over intervals of approximately107–108years. These variations may have significant effects on the pace of (biological) evolution through the elimination of terrestrial niches and the expansion of shallow-water marine niches. However, within the solar system, only the Earth experiences this kind of tectonism. Venus displays regional tectonism, characterized by rising diapirs within the plastic mantle. Impinging on the lithosphere, these plumes produce a range of structures of varying dimensions; the uplift of which would raise sea-level, were Venus to have oceans. Using Magellan observations of Venus, we model the impact of regional tectonism on sea-level for given areas of Venusian ocean, then compare the effect with terrestrial tectonic processes for similar oceanic area. We show that despite variation in the geographical extent of Venusian-style tectonic processes, the styles of regional tectonism on Venus can produce the same order of magnitude changes in sea-level, for a given area of ocean, as plate tectonics. Consequently, we examine some of the impacts of marine transgression on habitability and the evolution of life.
{"title":"The impact of tectonic-style on marine transgression and evolution","authors":"D. Stevenson","doi":"10.1017/S1473550421000082","DOIUrl":"https://doi.org/10.1017/S1473550421000082","url":null,"abstract":"Plate tectonics drives variation in sea-level, over intervals of approximately107–108years. These variations may have significant effects on the pace of (biological) evolution through the elimination of terrestrial niches and the expansion of shallow-water marine niches. However, within the solar system, only the Earth experiences this kind of tectonism. Venus displays regional tectonism, characterized by rising diapirs within the plastic mantle. Impinging on the lithosphere, these plumes produce a range of structures of varying dimensions; the uplift of which would raise sea-level, were Venus to have oceans. Using Magellan observations of Venus, we model the impact of regional tectonism on sea-level for given areas of Venusian ocean, then compare the effect with terrestrial tectonic processes for similar oceanic area. We show that despite variation in the geographical extent of Venusian-style tectonic processes, the styles of regional tectonism on Venus can produce the same order of magnitude changes in sea-level, for a given area of ocean, as plate tectonics. Consequently, we examine some of the impacts of marine transgression on habitability and the evolution of life.","PeriodicalId":13879,"journal":{"name":"International Journal of Astrobiology","volume":" ","pages":"1-15"},"PeriodicalIF":1.7,"publicationDate":"2021-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S1473550421000082","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48913884","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}
Pub Date : 2021-04-22DOI: 10.1017/S1473550421000124
S. Wickramarathna, R. Chandrajith, A. Senaratne, Varun Paul, P. Dash, S. Wickramasinghe, P. Biggs
Previous exploration missions have revealed Mars as a potential candidate for the existence of extraterrestrial life. If life could have existed beneath the Martian subsurface, biosignatures would have been preserved in iron-rich minerals. Prior investigations of terrestrial biosignatures and metabolic processes of geological analogues would be beneficial for identifying past metabolic processes on Mars, particularly morphological and chemical signatures indicative of past life, where biological components could potentially be denatured following continued exposure to extreme conditions. The objective of the research was to find potential implications for Martian subsurface life by characterizing morphological, mineralogical and microbial signatures of hematite deposits, both hematite rock and related soil samples, collected from Highland Complex of Sri Lanka. Rock samples examined through scanning electron microscopy-energy dispersive X-ray (SEM-EDX) spectroscopy. Analysis showed globular and spherical growth layers nucleated by bacteria. EDX results showed a higher iron to oxygen ratio in nuclei colonies compared to growth layers, which indicated a compositional variation due to microbial interaction. X-ray diffraction analysis of the hematite samples revealed variations in chemical composition along the vertical soil profile, with the top surface soil layer being particularly enriched with Fe2O3, suggesting internal dissolution of hematite through weathering. Furthermore, inductively coupled plasma-mass spectrometry analyses carried out on both rock and soil samples showed a possible indication of microbially induced mineral-weathering, particularly release of trapped trace metals in the parent rock. Microbial diversity analysis using 16S rRNA gene sequencing revealed that the rock sample was dominated by Actinobacteria and Proteobacteria, specifically, members of iron-metabolizing bacterial genera, including Mycobacterium, Arthrobacter, Amycolatopsis, Nocardia and Pedomicrobium. These results suggest that morphological and biogeochemical clues derived from studying the role of bacterial activity in hematite weathering and precipitation processes can be implemented as potential comparative tools to interpret similar processes that could have occurred on early Mars.
{"title":"Bacterial influence on the formation of hematite: implications for Martian dormant life","authors":"S. Wickramarathna, R. Chandrajith, A. Senaratne, Varun Paul, P. Dash, S. Wickramasinghe, P. Biggs","doi":"10.1017/S1473550421000124","DOIUrl":"https://doi.org/10.1017/S1473550421000124","url":null,"abstract":"\u0000 Previous exploration missions have revealed Mars as a potential candidate for the existence of extraterrestrial life. If life could have existed beneath the Martian subsurface, biosignatures would have been preserved in iron-rich minerals. Prior investigations of terrestrial biosignatures and metabolic processes of geological analogues would be beneficial for identifying past metabolic processes on Mars, particularly morphological and chemical signatures indicative of past life, where biological components could potentially be denatured following continued exposure to extreme conditions. The objective of the research was to find potential implications for Martian subsurface life by characterizing morphological, mineralogical and microbial signatures of hematite deposits, both hematite rock and related soil samples, collected from Highland Complex of Sri Lanka. Rock samples examined through scanning electron microscopy-energy dispersive X-ray (SEM-EDX) spectroscopy. Analysis showed globular and spherical growth layers nucleated by bacteria. EDX results showed a higher iron to oxygen ratio in nuclei colonies compared to growth layers, which indicated a compositional variation due to microbial interaction. X-ray diffraction analysis of the hematite samples revealed variations in chemical composition along the vertical soil profile, with the top surface soil layer being particularly enriched with Fe2O3, suggesting internal dissolution of hematite through weathering. Furthermore, inductively coupled plasma-mass spectrometry analyses carried out on both rock and soil samples showed a possible indication of microbially induced mineral-weathering, particularly release of trapped trace metals in the parent rock. Microbial diversity analysis using 16S rRNA gene sequencing revealed that the rock sample was dominated by Actinobacteria and Proteobacteria, specifically, members of iron-metabolizing bacterial genera, including Mycobacterium, Arthrobacter, Amycolatopsis, Nocardia and Pedomicrobium. These results suggest that morphological and biogeochemical clues derived from studying the role of bacterial activity in hematite weathering and precipitation processes can be implemented as potential comparative tools to interpret similar processes that could have occurred on early Mars.","PeriodicalId":13879,"journal":{"name":"International Journal of Astrobiology","volume":"1 1","pages":"1-15"},"PeriodicalIF":1.7,"publicationDate":"2021-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S1473550421000124","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48343338","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}
Pub Date : 2021-04-14DOI: 10.1017/S1473550421000112
J. Gale, A. Wandel
{"title":"On the border between Science and Science Fiction","authors":"J. Gale, A. Wandel","doi":"10.1017/S1473550421000112","DOIUrl":"https://doi.org/10.1017/S1473550421000112","url":null,"abstract":"","PeriodicalId":13879,"journal":{"name":"International Journal of Astrobiology","volume":"20 1","pages":"251-251"},"PeriodicalIF":1.7,"publicationDate":"2021-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S1473550421000112","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47533497","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}
Pub Date : 2021-04-07DOI: 10.1017/S1473550421000100
Alef dos Santos, E. Rodrigues-Filho, M. Homem
Lipids are among the organic substances that can work as biosignatures, indicating life in an environment. We present an experimental investigation concerning analysis of lipids from a microbial source deposited on the Mars Global Simulant (MGS-1) regolith by geomatrix-assisted laser desorption/ionization-mass spectrometry (GALDI-MS). Our results indicate that lipids from intact microbial cells of a black yeast strain can be detected in these mimetic samples of Martian soil. These lipid molecules are predominantly associated with the occurrence of adducts in the GALDI-MS spectra. The results can be helpful in the planning of future planetary missions.
{"title":"Analysis of microbial lipids deposited on Mars Global Simulant (MGS-1) by geomatrix-assisted laser desorption/ionization-mass spectrometry","authors":"Alef dos Santos, E. Rodrigues-Filho, M. Homem","doi":"10.1017/S1473550421000100","DOIUrl":"https://doi.org/10.1017/S1473550421000100","url":null,"abstract":"Lipids are among the organic substances that can work as biosignatures, indicating life in an environment. We present an experimental investigation concerning analysis of lipids from a microbial source deposited on the Mars Global Simulant (MGS-1) regolith by geomatrix-assisted laser desorption/ionization-mass spectrometry (GALDI-MS). Our results indicate that lipids from intact microbial cells of a black yeast strain can be detected in these mimetic samples of Martian soil. These lipid molecules are predominantly associated with the occurrence of adducts in the GALDI-MS spectra. The results can be helpful in the planning of future planetary missions.","PeriodicalId":13879,"journal":{"name":"International Journal of Astrobiology","volume":"1 1","pages":"1-7"},"PeriodicalIF":1.7,"publicationDate":"2021-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S1473550421000100","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47515108","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}
Pub Date : 2021-04-01DOI: 10.1017/S1473550421000057
Binod Prasad, Peter H. Richter, Nithya Vadakedath, Ferdinand W. M. Haag, S. M. Strauch, R. Mancinelli, Achim Schwarzwälder, Emmanuel Etcheparre, Nicolas Gaume, M. Lebert
Abstract The unique environment of space is characterized by several stress factors, including intense radiation, microgravity, high vacuum and extreme temperatures, among others. These stress conditions individually or in-combination influence genetics and gene regulation and bring potential evolutionary changes in organisms that would not occur under the Earth's gravity regime (1 × g). Thus, space can be explored to support the emergence of new varieties of microbes and plants, that when selected for, can exhibit increased growth and yield, improved resistance to pathogens, enhanced tolerance to drought, low nutrient and disease, produce new metabolites and others. These properties may be more difficult to achieve using other approaches under 1 × g. This review provides an overview of the space microgravity and ionizing radiation conditions that significantly influence organisms. Changes in the genomics, physiology, phenotype, growth and metabolites of organisms in real and simulated microgravity and radiation conditions are illustrated. Results of space biological experiments show that the space environment has significant scientific, technological and commercial potential. Combined these potentials can help address the future of life on Earth, part of goal e of astrobiology.
{"title":"How the space environment influences organisms: an astrobiological perspective and review","authors":"Binod Prasad, Peter H. Richter, Nithya Vadakedath, Ferdinand W. M. Haag, S. M. Strauch, R. Mancinelli, Achim Schwarzwälder, Emmanuel Etcheparre, Nicolas Gaume, M. Lebert","doi":"10.1017/S1473550421000057","DOIUrl":"https://doi.org/10.1017/S1473550421000057","url":null,"abstract":"Abstract The unique environment of space is characterized by several stress factors, including intense radiation, microgravity, high vacuum and extreme temperatures, among others. These stress conditions individually or in-combination influence genetics and gene regulation and bring potential evolutionary changes in organisms that would not occur under the Earth's gravity regime (1 × g). Thus, space can be explored to support the emergence of new varieties of microbes and plants, that when selected for, can exhibit increased growth and yield, improved resistance to pathogens, enhanced tolerance to drought, low nutrient and disease, produce new metabolites and others. These properties may be more difficult to achieve using other approaches under 1 × g. This review provides an overview of the space microgravity and ionizing radiation conditions that significantly influence organisms. Changes in the genomics, physiology, phenotype, growth and metabolites of organisms in real and simulated microgravity and radiation conditions are illustrated. Results of space biological experiments show that the space environment has significant scientific, technological and commercial potential. Combined these potentials can help address the future of life on Earth, part of goal e of astrobiology.","PeriodicalId":13879,"journal":{"name":"International Journal of Astrobiology","volume":"20 1","pages":"159 - 177"},"PeriodicalIF":1.7,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S1473550421000057","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44257531","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}
Pub Date : 2021-03-29DOI: 10.1017/S1473550421000070
R. C. Pereira, B. S. Teixeira, A. C. D. da Costa, D. Zaia
The modification of minerals with metals can promote changes in their surface and, consequently, in their physicochemical properties. Minerals could have played an important role in the origin of life as they can protect molecules against degradation by radiation and hydrolysis, pre-concentrate molecules from dilute solutions and catalyse the formation of polymers. Thus, the current work studied the modification of montmorillonite with Cu2+ and Fe3+ ions. These modified montmorillonites were used to study the interaction with adenine dissolved in distilled water and artificial seawater 4.0 Gy (Gy = billion years ago). The most important result of this work is that the adsorption of adenine onto modified montmorillonites is a complex interaction among adenine, salts in seawater and Cu2+/Fe3+-montmorillonite (Cu2+/Fe3+-Mont) . The adsorption of Cu2+ and Fe3+ onto montmorillonite decreased its surface area and pore volume. The Sips isotherm model showed the best fit of the data and n values indicate that the adenine adsorption process was homogeneous. The highest adenine adsorption was obtained in artificial seawater 4.0 Gy onto Fe3+-Mont at 60°C and the lowest in distilled water or artificial seawater 4.0 Gy onto montmorillonite [montmorillonite washed with distilled water (Mont-STD)] at 60°C. Adenine adsorption onto Mont-STD/montmorillonite modified with 500 ml of 0.1 mol l−1 of CuCl2 and Fe3+-Mont was an exothermic process and an endothermic process, respectively. For all adsorptions ΔG was negative. The adsorption of adenine onto Fe3+-Mont was ruled out by entropy and the other samples by enthalpy and entropy, being a major contribution for Gibbs free energy from enthalpy. The Fourier transform-infrared data indicate that the interaction of adenine with minerals may occur through the NH2 functional group.
用金属修饰矿物可以促进其表面的变化,从而改变其物理化学性质。矿物质可能在生命起源中发挥了重要作用,因为它们可以保护分子免受辐射和水解的降解,从稀释溶液中预先浓缩分子,并催化聚合物的形成。因此,本文研究了Cu2+和Fe3+离子对蒙脱土的改性。利用这些改性蒙脱石研究了在蒸馏水和人工海水中溶解的腺嘌呤(Gy =十亿年前)的相互作用。本工作最重要的结果是,腺嘌呤在改性蒙脱土上的吸附是腺嘌呤、海水中的盐和Cu2+/Fe3+-蒙脱土(Cu2+/Fe3+-Mont)之间的复杂相互作用。Cu2+和Fe3+在蒙脱土上的吸附减小了蒙脱土的表面积和孔隙体积。Sips等温线模型拟合最佳,n值表明腺嘌呤吸附过程是均匀的。60℃时,4.0 Gy的人工海水对Fe3+-Mont的腺嘌呤吸附量最高,60℃时,蒸馏水或4.0 Gy的人工海水对蒙脱土[蒸馏水洗涤蒙脱土(Mont-STD)]的腺嘌呤吸附量最低。用500 ml 0.1 mol l−1 CuCl2和Fe3+-Mont改性Mont-STD/蒙脱土对腺嘌呤的吸附分别为放热过程和吸热过程。对于所有吸附,ΔG为负。腺嘌呤在Fe3+-Mont上的吸附被熵排除,其他样品被焓和熵排除,是来自焓的吉布斯自由能的主要贡献。傅里叶变换红外数据表明,腺嘌呤与矿物质的相互作用可能是通过NH2官能团发生的。
{"title":"Interaction between adenine and Cu2+ and Fe3+-montmorillonites: a prebiotic chemistry experiment","authors":"R. C. Pereira, B. S. Teixeira, A. C. D. da Costa, D. Zaia","doi":"10.1017/S1473550421000070","DOIUrl":"https://doi.org/10.1017/S1473550421000070","url":null,"abstract":"The modification of minerals with metals can promote changes in their surface and, consequently, in their physicochemical properties. Minerals could have played an important role in the origin of life as they can protect molecules against degradation by radiation and hydrolysis, pre-concentrate molecules from dilute solutions and catalyse the formation of polymers. Thus, the current work studied the modification of montmorillonite with Cu2+ and Fe3+ ions. These modified montmorillonites were used to study the interaction with adenine dissolved in distilled water and artificial seawater 4.0 Gy (Gy = billion years ago). The most important result of this work is that the adsorption of adenine onto modified montmorillonites is a complex interaction among adenine, salts in seawater and Cu2+/Fe3+-montmorillonite (Cu2+/Fe3+-Mont) . The adsorption of Cu2+ and Fe3+ onto montmorillonite decreased its surface area and pore volume. The Sips isotherm model showed the best fit of the data and n values indicate that the adenine adsorption process was homogeneous. The highest adenine adsorption was obtained in artificial seawater 4.0 Gy onto Fe3+-Mont at 60°C and the lowest in distilled water or artificial seawater 4.0 Gy onto montmorillonite [montmorillonite washed with distilled water (Mont-STD)] at 60°C. Adenine adsorption onto Mont-STD/montmorillonite modified with 500 ml of 0.1 mol l−1 of CuCl2 and Fe3+-Mont was an exothermic process and an endothermic process, respectively. For all adsorptions ΔG was negative. The adsorption of adenine onto Fe3+-Mont was ruled out by entropy and the other samples by enthalpy and entropy, being a major contribution for Gibbs free energy from enthalpy. The Fourier transform-infrared data indicate that the interaction of adenine with minerals may occur through the NH2 functional group.","PeriodicalId":13879,"journal":{"name":"International Journal of Astrobiology","volume":"1 1","pages":"1-11"},"PeriodicalIF":1.7,"publicationDate":"2021-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S1473550421000070","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44323923","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}
Pub Date : 2021-03-29DOI: 10.1017/S1473550421000094
M. R. Edwards
Gale and Wandel (2021) describe my paper in IJA (Edwards, 2021) as having crossed the border of scientific plausibility into the realm of ‘science fiction.’ By science fiction, they presumably mean the ‘bad’ kind based on implausible or unsupported scientific concepts, such as time reversal, multiverses and indeed the warp drives of Star Trek they mention. As my paper is based only on current medical and scientific research, it does not make the transgression they imply. In it, I first reviewed artificial uterus systems and embryo cryopreservation as to whether they could potentially be used in space colonization or in recolonizing Earth after mass extinction events. While complete ectogenesis – the development of early-stage embryos to birth entirely outside the natural womb – is not yet available to serve this purpose, in the near future it likely will be (Bulletti et al., 2011; Räsänen and Smajdor, 2020). To illustrate the power and flexibility of the approach, I then discussed how such systems might be deployed in a comprehensive survival plan to handle a variety of extinction events, ranging from brief events in the very near future to the final, total extinction due to solar expansion (Ward and Brownlee, 2003; Klee, 2017). Gale and Wandel direct their criticisms primarily at these example survival missions, not the feasibility of ectogenesis with cryopreserved embryos per se. On one hand, they argue that near-term extinction events could be better handled by establishing colonies on Mars, on Jupiter’s moons or in O’Neill-type space colonies. Such colonies have dim prospects indeed. Recently it was shown, for example, that insufficient CO2 exists in known reservoirs on Mars to enable terraforming (Jakosky and Edwards, 2018), a sine qua non for Martian colonies. Jupiter’s moon Europa has indeed been proposed as a possible candidate for a space colony (e.g., the Artemis Project), but the extremely harsh radiation environment due to Jupiter’s magnetic storms and the ultra-frigid surface conditions there render such a colony as pure fantasy. Gerard O’Neill’s space colonies – city-sized structures holding up to a million people – rely on such notions as harvesting raw materials for manufacturing from the Moon or asteroids and constructing a totally self-supporting internal ecosystem. Such achievements again go far beyond what is technically feasible in the foreseeable future. Moreover, if by some miracle such colonies were in fact built, it would be Earth which would have to continually sustain them, rather than they protecting us from possible extinction. After a major extinction event, the vital connection with Earth for everything from medicines to spare parts would be lost and the colony would quickly collapse. In the model scheme I proposed, however, smaller spacecraft or space stations orbiting the Earth and carrying just a small number of astronauts/colonists would be one of the first lines of defence in short-duration events. These missio
Gale和Wandel(2021)将我在IJA (Edwards, 2021)上发表的论文描述为跨越了科学合理性的边界,进入了“科幻小说”的领域。他们所说的科幻小说,大概是指那些基于不可信或不受支持的科学概念的“坏”小说,比如时间逆转、多重宇宙,以及他们提到的《星际迷航》中的曲速引擎。由于我的论文仅基于当前的医学和科学研究,因此并没有他们所暗示的违法行为。在这篇文章中,我首先回顾了人工子宫系统和胚胎冷冻保存是否有可能用于太空殖民或在大规模灭绝事件后重新殖民地球。虽然完全的体外生殖——早期胚胎发育到完全在自然子宫外出生——目前还不能实现这一目的,但在不久的将来可能会实现(bullettti等人,2011;Räsänen and Smajdor, 2020)。为了说明这种方法的力量和灵活性,我随后讨论了如何在一个全面的生存计划中部署这样的系统来处理各种灭绝事件,从不久的将来的短暂事件到最终的,由于太阳膨胀而导致的完全灭绝(Ward and Brownlee, 2003;克利,2017)。Gale和Wandel的批评主要针对这些生存任务的例子,而不是用冷冻胚胎本身进行体外生殖的可行性。一方面,他们认为,通过在火星、木星的卫星或奥尼尔式的太空殖民地上建立殖民地,可以更好地应对近期的灭绝事件。这样的殖民地确实前景黯淡。例如,最近有研究表明,火星上已知储层中存在的二氧化碳不足,无法实现地球化(Jakosky和Edwards, 2018),而地球化是火星殖民地的必要条件。木星的卫星木卫二确实被提议作为太空殖民地的可能候选者(例如,阿尔忒弥斯计划),但由于木星磁暴的极端恶劣的辐射环境和那里超冷的表面条件,使得这样的殖民地纯粹是幻想。杰拉德·奥尼尔的太空殖民地——城市大小的建筑,最多可容纳100万人——依赖于从月球或小行星上收集制造原材料,并建立一个完全自给自足的内部生态系统等概念。在可预见的未来,这些成就再次远远超出了技术上可行的范围。此外,如果奇迹发生,这样的殖民地真的建成了,那将是地球必须继续维持它们,而不是它们保护我们免于可能的灭绝。在一次大灭绝事件之后,从药品到备件,与地球的重要联系将会消失,殖民地将迅速崩溃。然而,在我提出的模型方案中,较小的航天器或空间站绕地球运行,只携带少量宇航员/殖民者,将成为短期事件中的第一道防线之一。然后,这些任务可以通过体外生殖来延长,通过先用胚胎代替一些成年机组人员,然后再用胚胎代替所有成年机组人员,来处理规模越来越大、持续时间越来越长的事件。这些轨道任务连同在地下设施中展开的连锁、平行序列将是外生在大规模灭绝生存中最简单、也是最紧迫的应用,我将这个过程称为胚胎地球再殖民化(EER)。虽然这些EER任务对人类的生存来说是最关键的,但盖尔和万德尔把大部分精力都放在了技术上更具挑战性的系外行星殖民任务上,这些任务以前被称为胚胎太空殖民(ESC)。这些任务将需要避免灭绝事件,使地球永远不适合生命,包括最后一个由于太阳膨胀。他们首先认为,现在用现有的推进方法发射ESC航天器是毫无意义的,因为它们只会被具有更快推进力的后代宇宙飞船超越。首先,在通过设计大规模灭绝生存的EER任务获得多年的经验之前,很可能不会执行外行星任务。到那时,推进系统大概已经取得了重大进展。更重要的是,一个先进的文明,如果一再推迟派遣ESC飞船,就有可能在任何飞船发射之前就在灭绝事件中被消灭。在更深层次上,船是快还是慢并不重要。Gale和Wandel认为ESC船上的机械系统不能存活数千年或数百万年的观点是正确的:如果这些系统一直在运行的话。就像我
{"title":"Ectogenesis for survival in deep space and deep time: reply to Gale and Wandel","authors":"M. R. Edwards","doi":"10.1017/S1473550421000094","DOIUrl":"https://doi.org/10.1017/S1473550421000094","url":null,"abstract":"Gale and Wandel (2021) describe my paper in IJA (Edwards, 2021) as having crossed the border of scientific plausibility into the realm of ‘science fiction.’ By science fiction, they presumably mean the ‘bad’ kind based on implausible or unsupported scientific concepts, such as time reversal, multiverses and indeed the warp drives of Star Trek they mention. As my paper is based only on current medical and scientific research, it does not make the transgression they imply. In it, I first reviewed artificial uterus systems and embryo cryopreservation as to whether they could potentially be used in space colonization or in recolonizing Earth after mass extinction events. While complete ectogenesis – the development of early-stage embryos to birth entirely outside the natural womb – is not yet available to serve this purpose, in the near future it likely will be (Bulletti et al., 2011; Räsänen and Smajdor, 2020). To illustrate the power and flexibility of the approach, I then discussed how such systems might be deployed in a comprehensive survival plan to handle a variety of extinction events, ranging from brief events in the very near future to the final, total extinction due to solar expansion (Ward and Brownlee, 2003; Klee, 2017). Gale and Wandel direct their criticisms primarily at these example survival missions, not the feasibility of ectogenesis with cryopreserved embryos per se. On one hand, they argue that near-term extinction events could be better handled by establishing colonies on Mars, on Jupiter’s moons or in O’Neill-type space colonies. Such colonies have dim prospects indeed. Recently it was shown, for example, that insufficient CO2 exists in known reservoirs on Mars to enable terraforming (Jakosky and Edwards, 2018), a sine qua non for Martian colonies. Jupiter’s moon Europa has indeed been proposed as a possible candidate for a space colony (e.g., the Artemis Project), but the extremely harsh radiation environment due to Jupiter’s magnetic storms and the ultra-frigid surface conditions there render such a colony as pure fantasy. Gerard O’Neill’s space colonies – city-sized structures holding up to a million people – rely on such notions as harvesting raw materials for manufacturing from the Moon or asteroids and constructing a totally self-supporting internal ecosystem. Such achievements again go far beyond what is technically feasible in the foreseeable future. Moreover, if by some miracle such colonies were in fact built, it would be Earth which would have to continually sustain them, rather than they protecting us from possible extinction. After a major extinction event, the vital connection with Earth for everything from medicines to spare parts would be lost and the colony would quickly collapse. In the model scheme I proposed, however, smaller spacecraft or space stations orbiting the Earth and carrying just a small number of astronauts/colonists would be one of the first lines of defence in short-duration events. These missio","PeriodicalId":13879,"journal":{"name":"International Journal of Astrobiology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2021-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S1473550421000094","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44848606","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}
Pub Date : 2021-03-03DOI: 10.1017/S1473550420000427
N. Rcheulishvili, Dimitri Papukashvili, Y. Shakir, Yulin Deng, Ying Zhang
Abstract Corrosion of aluminium (Al) is a potential problem for spacecraft as this metal is used for various mechanical parts due to its strength, durability, etc. However, it can be corroded by certain factors including microbes. Studying microbes which can be implicated in microbiologically influenced corrosion (MIC) due to their extremophilic nature is of vital importance. In this current study, Al and acid-tolerant microbes were isolated from the samples of China space station assembly cleanroom surfaces; acidic environments can accelerate the corrosion process on metal surfaces. Nine bacterial and 10 fungal strains were identified with 16S ribosomal RNA gene/internal transcribed spacer region sequencing and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The dominant bacteria were of Bacillus, fungi of Penicillium and Aspergillus genera. Knowing the microbes which may be conveyed from the cleanrooms to the space stations with a potential capacity of Al degradation is important for long-term maintenance of station components. This study might aid in designing further researches of the aforementioned microorganisms and, therefore, contribute to the prevention of MIC.
{"title":"Acid and aluminium-tolerant microbes isolated from China space station assembly cleanroom surfaces and identified by 16S rRNA/ITS sequencing and MALDI-TOF MS","authors":"N. Rcheulishvili, Dimitri Papukashvili, Y. Shakir, Yulin Deng, Ying Zhang","doi":"10.1017/S1473550420000427","DOIUrl":"https://doi.org/10.1017/S1473550420000427","url":null,"abstract":"Abstract Corrosion of aluminium (Al) is a potential problem for spacecraft as this metal is used for various mechanical parts due to its strength, durability, etc. However, it can be corroded by certain factors including microbes. Studying microbes which can be implicated in microbiologically influenced corrosion (MIC) due to their extremophilic nature is of vital importance. In this current study, Al and acid-tolerant microbes were isolated from the samples of China space station assembly cleanroom surfaces; acidic environments can accelerate the corrosion process on metal surfaces. Nine bacterial and 10 fungal strains were identified with 16S ribosomal RNA gene/internal transcribed spacer region sequencing and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The dominant bacteria were of Bacillus, fungi of Penicillium and Aspergillus genera. Knowing the microbes which may be conveyed from the cleanrooms to the space stations with a potential capacity of Al degradation is important for long-term maintenance of station components. This study might aid in designing further researches of the aforementioned microorganisms and, therefore, contribute to the prevention of MIC.","PeriodicalId":13879,"journal":{"name":"International Journal of Astrobiology","volume":"20 1","pages":"133 - 141"},"PeriodicalIF":1.7,"publicationDate":"2021-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S1473550420000427","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41715180","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}
Pub Date : 2021-02-26DOI: 10.1017/S1473550421000033
A. K. Arora, Pankaj Kumar
Abstract Studies on the interaction of biomolecules with inorganic compounds, mainly mineral surfaces, are of great concern in identifying their role in chemical evolution and origins of life. Metal oxides are the major constituents of earth and earth-like planets. Hence, studies on the interaction of biomolecules with these minerals are the point of concern for the study of the emergence of life on different planets. Zirconium oxide is one of the metal oxides present in earth's crust as it is a part of several types of rocks found in sandy areas such as beaches and riverbeds, e.g. pebbles of baddeleyite. Different metal oxides have been studied for their role in chemical evolution but no studies have been reported about the role of zirconium oxide in chemical evolution and origins of life. Therefore, studies were carried out on the interaction of ribonucleic acid constituents, 5′-CMP (cytidine monophosphate), 5′-UMP (uridine monophosphate), 5′-GMP (guanosine monophosphate) and 5′-AMP (adenosine monophosphate), with zirconium oxide. Synthesized zirconium oxide particles were characterized by using vibrating sample magnetometer, X-Ray Diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy. Zirconia particles were in the nanometre range, from 14 to 27 nm. The interaction of zirconium oxide with ribonucleic acid constituents was performed in the concentration range of 5 × 10−5–300 × 10−5 M. Interaction studies were carried out in three mediums; acidic (pH 4.0), neutral (pH 7.0) and basic (pH 9.0). At neutral pH, maximum interaction was observed. The interaction of zirconium oxide with 5′-UMP was 49.45% and with 5′-CMP 67.98%, while with others it was in between. Interaction studies were Langmurian in nature. Xm and KL values were calculated. Infrared spectral studies of ribonucleotides, metal oxide and ribonucleotide–metal oxide adducts were carried out to find out the interactive sites. It was observed that the nitrogen base and phosphate moiety of ribonucleotides interact with the positive charge surface of metal oxide. SEM was also carried out to study the adsorption. The results of the present study favour the important role of zirconium oxide in concentrating the organic molecules from their dilute aqueous solutions in primeval seas.
{"title":"Prebiotic studies on the interaction of zirconia nanoparticles and ribose nucleotides and their role in chemical evolution","authors":"A. K. Arora, Pankaj Kumar","doi":"10.1017/S1473550421000033","DOIUrl":"https://doi.org/10.1017/S1473550421000033","url":null,"abstract":"Abstract Studies on the interaction of biomolecules with inorganic compounds, mainly mineral surfaces, are of great concern in identifying their role in chemical evolution and origins of life. Metal oxides are the major constituents of earth and earth-like planets. Hence, studies on the interaction of biomolecules with these minerals are the point of concern for the study of the emergence of life on different planets. Zirconium oxide is one of the metal oxides present in earth's crust as it is a part of several types of rocks found in sandy areas such as beaches and riverbeds, e.g. pebbles of baddeleyite. Different metal oxides have been studied for their role in chemical evolution but no studies have been reported about the role of zirconium oxide in chemical evolution and origins of life. Therefore, studies were carried out on the interaction of ribonucleic acid constituents, 5′-CMP (cytidine monophosphate), 5′-UMP (uridine monophosphate), 5′-GMP (guanosine monophosphate) and 5′-AMP (adenosine monophosphate), with zirconium oxide. Synthesized zirconium oxide particles were characterized by using vibrating sample magnetometer, X-Ray Diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy. Zirconia particles were in the nanometre range, from 14 to 27 nm. The interaction of zirconium oxide with ribonucleic acid constituents was performed in the concentration range of 5 × 10−5–300 × 10−5 M. Interaction studies were carried out in three mediums; acidic (pH 4.0), neutral (pH 7.0) and basic (pH 9.0). At neutral pH, maximum interaction was observed. The interaction of zirconium oxide with 5′-UMP was 49.45% and with 5′-CMP 67.98%, while with others it was in between. Interaction studies were Langmurian in nature. Xm and KL values were calculated. Infrared spectral studies of ribonucleotides, metal oxide and ribonucleotide–metal oxide adducts were carried out to find out the interactive sites. It was observed that the nitrogen base and phosphate moiety of ribonucleotides interact with the positive charge surface of metal oxide. SEM was also carried out to study the adsorption. The results of the present study favour the important role of zirconium oxide in concentrating the organic molecules from their dilute aqueous solutions in primeval seas.","PeriodicalId":13879,"journal":{"name":"International Journal of Astrobiology","volume":"20 1","pages":"142 - 149"},"PeriodicalIF":1.7,"publicationDate":"2021-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S1473550421000033","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43953102","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}