International Journal of Astrobiology最新文献_第2页

Detection of dsrAB operon expression in Desulfotalea psychrophila cells subjected to simulated Martian conditions of temperature and regolith's sulphate minerals composition 模拟火星温度和风化层硫酸盐矿物组成条件下嗜冷Desulfotalea细胞中dsrAB操纵子表达的检测

IF 1.7 4区物理与天体物理 Q2 Physics and Astronomy

International Journal of Astrobiology

Pub Date : 2023-09-07 DOI: 10.1017/s1473550423000198

Sergio Mosquera, Mack Ivey, Vincent F. Chevrier

Discoveries of transient liquid water in the Martian polar caps and the presence of liquid lakes and subsurface oceans in icy satellites have increased the interest of scientists in the capabilities of terrestrial extremophiles to grow and remain metabolically active in these extreme environments. The principal goal of this research is to understand the metabolic capacity of the anaerobic psychrophile, Desulfotalea psychrophila, cultured at subfreezing temperatures in media containing various concentrations of sulphate minerals. In this regard, our experiments focused on the detection of D. psychrophila survival and active metabolism, employing a biochamber that can recreate Martian temperatures. Using standard bacteriological methods for determining growth, combined with molecular and enzymatic determination of sulphate reduction, we have found that D. psychrophila is capable to carry out biological processes at temperatures down to −5°C, at concentrations that range from 0.35 to 18 wt% of MgSO4, 0.1 wt% of CaSO4 and 10 to 14 wt% of FeSO4 in which the highest sulphate concentration gradually returned the biosynthetic rate to basal limits, and the lowest temperature decreased bacterial cell division. These chemical salts, whose ions are classified as chaotropes, are known to act by maintaining water molecules in liquid state at subfreezing temperatures and by altering the stability of cellular components. This ‘chaotropic effect’ could potentially benefit the microbial metabolic activity up to a concentration in which cellular viability is jeopardized. Consequently, our hypothesis is directed towards the detection of metabolic activity as an indirect measurement of the potential influence of these ions in the flexibility/functionality of biological structures that at cold temperatures are highly rigid, compact and partially/non-functional due to water freezing. Studies of this type of microorganism are critical considering the possibility of survival and colonization of psychrophilic sulphate reducers in other planets and icy satellites.

火星极地冰盖中瞬态液态水的发现，以及结冰卫星中液态湖和地下海洋的存在，增加了科学家对陆地极端微生物在这些极端环境中生长和保持代谢活性的能力的兴趣。本研究的主要目标是了解厌氧嗜冷菌脱硫嗜冷菌的代谢能力，该菌在低于冰点的温度下，在含有不同浓度硫酸盐矿物质的培养基中培养。在这方面，我们的实验重点是检测嗜冷D.嗜冷菌的生存和活性代谢，使用了一种可以重现火星温度的生物琥珀。使用测定生长的标准细菌学方法，结合硫酸盐还原的分子和酶法测定，我们发现嗜冷假单胞菌能够在低至−5°C的温度下，在0.35至18wt%的MgSO4浓度范围内进行生物过程，0.1wt%的CaSO4和10-14wt%的FeSO4，其中最高的硫酸盐浓度逐渐使生物合成速率恢复到基础极限，并且最低的温度降低了细菌细胞分裂。众所周知，这些化学盐的离子被归类为超液，其作用是在低于冰点的温度下保持水分子的液态，并改变细胞成分的稳定性。这种“离液效应”可能有利于微生物的代谢活性，达到危及细胞活力的浓度。因此，我们的假设是针对代谢活性的检测，作为对这些离子对生物结构的灵活性/功能性的潜在影响的间接测量，这些生物结构在低温下由于水冻结而高度刚性、紧凑和部分/非功能性。考虑到嗜冷硫酸盐还原剂在其他行星和结冰卫星中生存和定殖的可能性，对这类微生物的研究至关重要。

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引用次数: 0

Astrobioethical reflections on humanity and its consideration as multi- and interplanetary 宇宙生物伦理学对人类的反思及其作为多行星和行星际的考虑

IF 1.7 4区物理与天体物理 Q2 Physics and Astronomy

International Journal of Astrobiology

Pub Date : 2023-08-07 DOI: 10.1017/s1473550423000162

Octavio A. Chon-Torres, J. Chela-Flores

We discuss in the context of astrobiology three aspects of the possible evolution of humanity. In addition, from astrobioethics -the study of the moral implications in astrobiology- we ask whether it is necessary to develop new concepts. Thus, it is concluded that we have already started our transition towards an interplanetary humanity; that our actions in the face of the discovery of extraterrestrial life will depend on the context in which we find ourselves; and that it is important to develop new and updated concepts for the scenarios to be faced by the eventual evolution of humanity in space.

我们在天体生物学的背景下讨论了人类可能进化的三个方面。此外，从天体生物伦理学——研究天体生物学中的道德含义——我们询问是否有必要发展新的概念。因此，我们得出的结论是，我们已经开始向星际人类过渡；面对外星生命的发现，我们的行动将取决于我们所处的环境；重要的是，为人类在太空的最终进化所面临的情景制定新的和更新的概念。

引用次数: 0

The challenging history of other Earths 其他地球富有挑战性的历史

IF 1.7 4区物理与天体物理 Q2 Physics and Astronomy

International Journal of Astrobiology

Pub Date : 2023-08-03 DOI: 10.1017/s1473550423000174

C. Graney

This paper provides an overview of recent historical research regarding scientifically-informed challenges to the idea that the stars are other suns orbited by other inhabited earths – an idea that came to be known as ‘the Plurality of Worlds’. Johannes Kepler in the 17th century, Jacques Cassini in the 18th and William Whewell in the 19th each argued against ‘pluralism’ based on what in their respective times was solid science. Nevertheless, pluralism remained popular despite these and other scientific challenges. This history will be of interest to the astronomical community so that it is better positioned to avoid difficulties should the historical trajectory of pluralism continue, especially as it persists in the popular imagination.

这篇论文概述了最近的历史研究，这些研究以科学为依据，对恒星是由其他有人居住的地球环绕的其他太阳这一观点提出了挑战——这一观点后来被称为“世界多元论”。17世纪的约翰内斯·开普勒，18世纪的雅克·卡西尼和19世纪的威廉·休厄尔都反对“多元主义”，他们都是基于他们各自时代的坚实科学。然而，尽管面临这些和其他科学挑战，多元主义仍然很受欢迎。这段历史将引起天文学界的兴趣，这样，如果多元主义的历史轨迹继续下去，特别是在大众的想象中，它就能更好地避免困难。

引用次数: 0

Astrovirology: how viruses enhance our understanding of life in the Universe. 天体病毒学：病毒如何增强我们对宇宙生命的理解

IF 1.7 4区物理与天体物理 Q2 Physics and Astronomy

International Journal of Astrobiology

Pub Date : 2023-08-01 Epub Date: 2023-04-05 DOI: 10.1017/s1473550423000058

Gareth Trubl, Kenneth M Stedman, Kathryn F Bywaters, Emily E Matula, Pacifica Sommers, Simon Roux, Nancy Merino, John Yin, Jason T Kaelber, Aram Avila-Herrera, Peter Anto Johnson, John Christy Johnson, Schuyler Borges, Peter K Weber, Jennifer Pett-Ridge, Penelope J Boston

Viruses are the most numerically abundant biological entities on Earth. As ubiquitous replicators of molecular information and agents of community change, viruses have potent effects on the life on Earth, and may play a critical role in human spaceflight, for life-detection missions to other planetary bodies and planetary protection. However, major knowledge gaps constrain our understanding of the Earth's virosphere: (1) the role viruses play in biogeochemical cycles, (2) the origin(s) of viruses and (3) the involvement of viruses in the evolution, distribution and persistence of life. As viruses are the only replicators that span all known types of nucleic acids, an expanded experimental and theoretical toolbox built for Earth's viruses will be pivotal for detecting and understanding life on Earth and beyond. Only by filling in these knowledge and technical gaps we will obtain an inclusive assessment of how to distinguish and detect life on other planetary surfaces. Meanwhile, space exploration requires life-support systems for the needs of humans, plants and their microbial inhabitants. Viral effects on microbes and plants are essential for Earth's biosphere and human health, but virus-host interactions in spaceflight are poorly understood. Viral relationships with their hosts respond to environmental changes in complex ways which are difficult to predict by extrapolating from Earth-based proxies. These relationships should be studied in space to fully understand how spaceflight will modulate viral impacts on human health and life-support systems, including microbiomes. In this review, we address key questions that must be examined to incorporate viruses into Earth system models, life-support systems and life detection. Tackling these questions will benefit our efforts to develop planetary protection protocols and further our understanding of viruses in astrobiology.

病毒是地球上数量最多的生物实体。作为分子信息的普遍复制者和社区变化的推动者，病毒对地球上的生命有着强大的影响，并可能在载人航天、对其他行星体的生命探测任务和行星保护中发挥关键作用。然而，主要的知识差距限制了我们对地球病毒圈的理解：（1）病毒在生物地球化学循环中的作用，（2）病毒的起源，以及（3）病毒在生命进化、分布和持久性中的参与。由于病毒是唯一跨越所有已知类型核酸的复制因子，为地球病毒构建的扩展实验和理论工具箱将对检测和理解地球内外的生命至关重要。只有填补这些知识和技术空白，我们才能对如何区分和探测其他行星表面的生命进行全面评估。与此同时，太空探索需要生命支持系统来满足人类、植物及其微生物居民的需求。病毒对微生物和植物的影响对地球生物圈和人类健康至关重要，但人们对太空飞行中病毒与宿主的相互作用知之甚少。病毒与宿主的关系以复杂的方式对环境变化做出反应，这很难通过基于地球的代理来预测。这些关系应该在太空中进行研究，以充分了解太空飞行将如何调节病毒对人类健康和生命支持系统（包括微生物组）的影响。在这篇综述中，我们讨论了必须研究的关键问题，以将病毒纳入地球系统模型、生命支持系统和生命检测。解决这些问题将有利于我们制定行星保护协议，并进一步了解天体生物学中的病毒。

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引用次数: 0

Information gain as a tool for assessing biosignature missions 信息获取作为评估生物签名任务的工具

IF 1.7 4区物理与天体物理 Q2 Physics and Astronomy

International Journal of Astrobiology

Pub Date : 2023-07-13 DOI: 10.1017/s1473550423000150

B. Fields, Sohom Gupta, M. Sandora

We propose the mathematical notion of information gain as a way of quantitatively assessing the value of biosignature missions. This makes it simple to determine how mission value depends on design parameters, prior knowledge and input assumptions. We demonstrate the utility of this framework by applying it to a plethora of case examples: the minimal number of samples needed to determine a trend in the occurrence rate of a signal as a function of an environmental variable, and how much cost should be allocated to each class of object; the relative impact of false positives and false negatives, with applications to Enceladus data and how best to combine two signals; the optimum tradeoff between resolution and coverage in the search for lurkers or other spatially restricted signals, with application to our current state of knowledge for solar system bodies; the best way to deduce a habitability boundary; the optimal amount of money to spend on different mission aspects; when to include an additional instrument on a mission; the optimal mission lifetime; and when to follow/challenge the predictions of a habitability model. In each case, we generate concrete, quantitative recommendations for optimizing mission design, mission selection and/or target selection.

我们提出了信息增益的数学概念，作为定量评估生物签名任务价值的一种方法。这使得确定任务价值如何取决于设计参数、先验知识和输入假设变得简单。我们通过将该框架应用于大量案例来证明其实用性：确定作为环境变量函数的信号发生率趋势所需的最小样本数，以及应为每类对象分配多少成本；假阳性和假阴性的相对影响，对恩克拉多斯数据的应用，以及如何最好地组合两个信号；在寻找潜伏者或其他空间受限信号的过程中，分辨率和覆盖率之间的最佳折衷，应用于我们目前对太阳系天体的了解；推断可居住性边界的最佳方法；用于不同任务方面的最佳资金数额；何时在任务中增加一项文书；最佳任务寿命；以及何时遵循/质疑可居住性模型的预测。在每种情况下，我们都会为优化任务设计、任务选择和/或目标选择提出具体、定量的建议。

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引用次数: 0

Iron reduction as a viable metabolic pathway in Enceladus’ ocean 铁还原是土卫二海洋中可行的代谢途径

IF 1.7 4区物理与天体物理 Q2 Physics and Astronomy

International Journal of Astrobiology

Pub Date : 2023-07-06 DOI: 10.1017/s1473550423000125

Matthew J. Roche, M. Fox‐Powell, R. Hamp, J. Byrne

Recent studies postulated the viability of a suite of metabolic pathways in Enceladus’ ocean motivated by the detection of H2 and CO2 in the plumes – evidence for available free energy for methanogenesis driven by hydrothermal activity at the moon's seafloor. However, these have not yet been explored in detail. Here, a range of experiments were performed to investigate whether microbial iron reduction could be a viable metabolic pathway in the ocean by iron-reducing bacteria such as Geobacter sulfurreducens. This study has three main outcomes: (i) the successful reduction of a number of crystalline Fe(III)-bearing minerals predicted to be present at Enceladus was shown to take place to differing extents using acetate as an electron donor; (ii) substantial bacterial growth in a simulated Enceladus ocean medium was demonstrated using acetate and H2(g) separately as electron donors; (iii) microbial iron reduction of ferrihydrite was shown to partially occur at pH 9, the currently accepted value for Enceladus’ ocean, whilst being severely hindered at the ambient ocean temperature of 0°. This study proposes the possibilities for biogeochemical iron cycling in Enceladus’ ocean, suggesting that a strain of iron-reducing bacteria can effectively function under Enceladus-like conditions.

最近的研究假设了土卫二海洋中一系列代谢途径的可行性，这些代谢途径是由探测到的羽流中的H2和CO2驱动的——这是由土卫二海底热液活动驱动的甲烷生成的可用自由能量的证据。然而，这些尚未被详细探讨。在这里，进行了一系列实验来研究微生物铁还原是否可能是海洋中铁还原细菌(如硫还原地杆菌)的一种可行的代谢途径。这项研究有三个主要结果:(i)使用醋酸盐作为电子供体，预测在土卫二上存在的一些含铁(III)矿物晶体的成功还原被证明在不同程度上发生;(ii)分别使用乙酸和H2(g)作为电子供体，证明了细菌在模拟的Enceladus海洋培养基中可以大量生长;(iii)水合铁的微生物铁还原部分发生在目前公认的土卫二海洋pH值为9时，而在环境海洋温度为0°时则严重受阻。这项研究提出了土卫二海洋中生物地球化学铁循环的可能性，表明一种铁还原细菌可以在类似土卫二的条件下有效地发挥作用。

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引用次数: 1

Dehydrated thin film media to rapidly estimate bioburden for planetary protection flight implementation 脱水薄膜介质快速估算生物负荷，实现行星保护飞行

IF 1.7 4区物理与天体物理 Q2 Physics and Astronomy

International Journal of Astrobiology

Pub Date : 2023-07-03 DOI: 10.1017/s1473550423000149

Zachary S. Dean, Kristina Stott, W. Schubert, E. Seto, S. Chandrapati

Planetary Protection (PP) is the practice of safeguarding solar system bodies from terrestrial biological contamination and screening the Earth against potentially harmful extraterrestrial biological contamination. On Earth, cleanrooms and spacecraft surfaces are assayed using swabs and wipes that are then heat shocked for 15 min at 80°C to select for spores. The samples are further processed using the pour-plate method and Petri plates (TSA plates), with trypticase soy agar (TSA) serving as the growth medium. This sampling and processing procedure, called the NASA Standard Assay (NSA), is used by PP engineers around the world. Recent years have seen an increase in the incorporation of state-of-the-art technology, such as membrane filtration, into the NSA, with a push for implementing environmentally friendly technology into day-to-day activities. Dehydrated thin film media, such as Petrifilm Rapid Aerobic Count (RAC) plates, suit these goals as an alternative method to TSA plates. RAC plates show bacterial growth (and distinguish colonies from foreign particles such as bubbles) faster than TSA plates due to the incorporation of chromogenic colour indicators in the media. RAC plates also possess a much smaller environmental footprint than TSA plates, and are designed to evaluate even some of the challenging-to-detect environmental organisms, including spreaders that fill over 25% of the plate area in only a few hours. With these benefits in mind the PP Group at the NASA Jet Propulsion Laboratory took on the task of comparing RAC plates directly to TSA plates within the context of the NSA. Not only were the RAC plates able to detect surface environmental samples and in vitro spiked samples equivalent to NSA-processed TSA plates, but spreader organisms were countable on RAC plates at culture densities 10- to 100-fold greater than on TSA plates. In addition, RAC plates showed a robust, linear detection capability when challenged with membrane filter incorporation and organisms were easily acquired from RAC plates for archiving or post-processing experiments including MALDI-TOF bacterial identification. With their ease of use, small footprint, and both rapid and accurate bioburden measurements, RAC plates have the potential to overcome limitations posed by current PP culturing protocols.

行星保护(PP)是保护太阳系天体免受地球生物污染和保护地球免受潜在有害的外星生物污染的实践。在地球上，用棉签和湿巾对洁净室和航天器表面进行分析，然后在80°C下加热15分钟，以选择孢子。以胰酶大豆琼脂(TSA)为生长培养基，采用倒板法和皮氏板(TSA板)对样品进行进一步处理。这种采样和处理程序被称为NASA标准分析(NSA)，被世界各地的PP工程师使用。近年来，美国国家安全局越来越多地采用最先进的技术，如膜过滤，并推动将环保技术应用于日常活动。脱水薄膜介质，如石化膜快速好氧计数(RAC)板，适合这些目标，作为TSA板的替代方法。由于在培养基中加入了显色指示剂，RAC板比TSA板显示细菌生长(并区分菌落和外来颗粒，如气泡)更快。RAC板的环境足迹也比TSA板小得多，并且设计用于评估甚至一些难以检测的环境生物，包括在几个小时内填满超过25%的板面积的扩散器。考虑到这些好处，NASA喷气推进实验室的PP小组承担了在NSA背景下直接比较RAC板和TSA板的任务。RAC板不仅能够检测表面环境样品和相当于nsa处理过的TSA板的体外加标样品，而且在RAC板上可以计数到传播菌，其培养密度比TSA板高10到100倍。此外，RAC板在加入膜过滤器时表现出强大的线性检测能力，并且很容易从RAC板上获得生物体用于存档或后处理实验，包括MALDI-TOF细菌鉴定。RAC板具有易于使用，占地面积小，快速准确的生物负荷测量，具有克服当前PP培养方案所带来的限制的潜力。

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引用次数: 0

Houston, we have a problem…or do we? The trajectory of astrobioethics and Indigenous thought 休斯顿，我们有问题…还是我们有问题？天体生物伦理学的轨迹与本土思想

IF 1.7 4区物理与天体物理 Q2 Physics and Astronomy

International Journal of Astrobiology

Pub Date : 2023-06-26 DOI: 10.1017/s1473550423000137

Ried Mackay

At the 2022 meeting of the American Society for Bioethics and Medical Humanities, a new affinity group was formed: astrobioethics. This is the branch of bioethics for space exploration, extraterrestrial environments and possible extraterrestrial organisms. Bioethics has traditionally operated from Western/Global North dominated thought structures and it is difficult to introduce alternative frameworks. However, astrobioethics is forming and is primed to include alternative frameworks, such as pre-Columbian Indigenous American philosophy/ethics and Global South frameworks and knowledge. The methods utilized include Indigenous research methodologies and standpoint, an overview of Indigenous American philosophy/ethics, and reflection on how this may impact astrobioethical considerations of space exploration. Indigenous philosophies and ethics consider space exploration and its associated risks and impacts on potential extraterrestrial lifeforms, systems and environments. The nuances of using terms like ‘colonization’ are considered and the paper concludes by considering how Méxica philosophical concepts and the four main Indigenous pragmatic dimensions can interact with established bioethical principles to guide future space exploration.

在2022年美国生命伦理学和医学人文学会的会议上，成立了一个新的亲密团体:天体生物伦理学。这是空间探索、地外环境和可能的地外生物的生物伦理学的一个分支。生物伦理学传统上是由西方/全球北方主导的思想结构运作的，很难引入替代框架。然而，天体生物伦理学正在形成，并准备纳入其他框架，如前哥伦布美洲土著哲学/伦理学和全球南方框架和知识。所使用的方法包括土著研究方法和观点，对美洲土著哲学/伦理的概述，以及对这可能如何影响空间探索的天体生物伦理考虑的思考。土著哲学和伦理考虑空间探索及其对潜在的地外生命形式、系统和环境的相关风险和影响。使用“殖民化”等术语的细微差别被考虑在内，论文的结论是考虑了m西卡哲学概念和四个主要的土著实用主义维度如何与已建立的生物伦理原则相互作用，以指导未来的太空探索。

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引用次数: 0

Astrobiology: resolution of the statistical Drake equation by Maccone's lognormal method in 50 steps 天体生物学：用Maccone的对数正态方法在50步中解析统计Drake方程

IF 1.7 4区物理与天体物理 Q2 Physics and Astronomy

International Journal of Astrobiology

Pub Date : 2023-06-14 DOI: 10.1017/s1473550423000113

E. Mieli, A. Valli, C. Maccone

The authors use the mathematical tool of Maccone's lognormal distribution to further factor the Drake equation, which calculates the number of advanced civilizations in the galaxy, from the seven original levels of the Drake equation to 49 levels of overall analysis. The Maccone approach, in fact, supported by the central limit theorem, becomes more reliable the more levels are introduced. The resulting study necessarily draws upon an array of disciplines ranging from astronomy, chemistry and geology to biology, palaeontology and futurology. The final result calculates the number of planetary systems suitable for life in its various stages of development: those which have probably hosted life in the past and those which still host it at its various evolutionary levels. The final evolutionary level is the so-called galactic civilization (often called ETC, or extraterrestrial civilizations). The number of resulting galactic civilizations is divided between static civilizations, which do not move around the galaxy and whose Kardašëv rating is still low (<1.4), of which we find three examples (we ourselves plus, perhaps, two others), and potentially dynamic civilizations, which move around the galaxy and have a sufficiently high Kardašëv rating (≥1.4), of which we find 2000.

作者使用Maccone的对数正态分布这一数学工具，将计算银河系中先进文明数量的德雷克方程从最初的7个层次进一步分解为49个层次的整体分析。事实上，在中心极限定理的支持下，Maccone方法引入的层次越多越可靠。由此产生的研究必然涉及一系列学科，从天文学、化学、地质学到生物学、古生物学和未来学。最后的结果计算出适合生命在不同发展阶段的行星系统的数量:那些在过去可能有生命存在的行星系统，以及那些在不同进化阶段仍有生命存在的行星系统。最后一个进化层次是所谓的银河文明(通常被称为ETC，或外星文明)。由此产生的星系文明的数量分为静态文明，它们不会在星系周围移动，其Kardašëv评级仍然很低(<1.4)，我们发现了三个例子(我们自己加上，也许，另外两个)，以及潜在的动态文明，它们在星系周围移动，并且具有足够高的Kardašëv评级(≥1.4)，我们发现了2000个。

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引用次数: 0

The future of intelligence in the Universe: a call for humility 宇宙智慧的未来：谦逊的呼唤

IF 1.7 4区物理与天体物理 Q2 Physics and Astronomy

International Journal of Astrobiology

Pub Date : 2023-06-01 DOI: 10.1017/s1473550423000101

S. Friederich, S. Wenmackers

Recent astrophysical findings suggest that the era during which the Universe is habitable has just begun. This raises the question whether the entire Universe may at some point in the future be filled with intelligent life. Hanson et al. (2021, The Astrophysical Journal922, 182) argued that we can be confident that the Universe will, by cosmic standards, soon be dominated by imperialist civilizations which expand rapidly, persist long and make drastic changes to the volumes they control. The main motivation for this ‘grabby civilizations’ hypothesis is that it supposedly provides a good explanation of why we are so early in cosmic history. In this paper, we criticize this motivation and suggest that it fails, for reasons analogous to why the notorious Doomsday argument fails. In the last part of the paper we broaden our discussion and argue that it may be rational to assign a rather low prior probability to the grabby civilizations hypothesis. For instance, if there are any civilizations that expand rapidly and indefinitely, they may well not make any drastic changes to the volumes they inhabit, potentially for strategic reasons. Hence, we call for epistemic caution and humility regarding the question of the long-term evolution of intelligence in the Universe.

最近的天体物理学发现表明，宇宙宜居的时代才刚刚开始。这就提出了一个问题，即整个宇宙是否在未来的某个时刻充满了智慧生命。汉森等人（2021，《天体物理杂志》922182）认为，我们可以相信，按照宇宙标准，宇宙很快就会被帝国主义文明所主宰，这些文明迅速扩张，长期存在，并对其控制的体积做出巨大改变。这种“贪婪文明”假说的主要动机是，它被认为为我们为什么处于宇宙历史的早期提供了一个很好的解释。在本文中，我们批评了这种动机，并认为它失败了，原因类似于臭名昭著的末日论失败的原因。在论文的最后一部分，我们扩大了我们的讨论范围，并认为将相当低的先验概率分配给grabby文明假说可能是合理的。例如，如果有任何文明快速而无限期地扩张，它们很可能不会对其居住的数量做出任何剧烈的改变，这可能是出于战略原因。因此，我们呼吁对宇宙中智力的长期进化问题保持认识上的谨慎和谦逊。

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引用次数: 0