International Journal of Astrobiology最新文献_第9页

Astrobiologists are rational but not Bayesian 天体生物学家是理性的，但不是贝叶斯

IF 1.7 4区物理与天体物理

International Journal of Astrobiology Pub Date : 2021-08-01 DOI: 10.1017/s1473550421000185

W. Bains, J. Petkowski

{"title":"Astrobiologists are rational but not Bayesian","authors":"W. Bains, J. Petkowski","doi":"10.1017/s1473550421000185","DOIUrl":"https://doi.org/10.1017/s1473550421000185","url":null,"abstract":"\u0000 The search for biosignatures is likely to generate controversial results, with no single biosignature being clear proof of the presence of life. Bayesian statistical frameworks have been suggested as a tool for testing the effect that a new observation has on our belief in the presence of life on another planet. We test this approach here using the tentative discovery of phosphine on Venus as an example of a possible detection of a biosignature on an otherwise well-characterized planet. We report on a survey of astrobiologists' views on the likelihood of life on Enceladus, Europa, Mars, Titan and Venus before the announcement of the detection of phosphine in Venus' atmosphere (the Bayesian Prior Probability) and after the announcement (the Posterior Probability). Survey results show that respondents have a general view on the likelihood of life on any world, independent of the relative ranking of specific bodies, and that there is a distinct ‘fans of icy moons’ sub-community. The announcement of the potential presence of phosphine on Venus resulted in the community showing a small but significant increase in its confidence that there was life on Venus; nevertheless the community still considers Venus to be the least likely abode of life among the five targets considered, last after Titan. We derive a Bayesian formulation that explicitly includes both the uncertainty in the interpretation of the signal as well as uncertainty in whether phosphine on Venus could have been produced by life. We show that although the community has shown rational restraint about a highly unexpected and still tentative detection, their changing expectations do not fit a Bayesian model.","PeriodicalId":13879,"journal":{"name":"International Journal of Astrobiology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/s1473550421000185","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49284101","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}

引用次数: 4

A brief history of the term ‘habitable zone’ in the 19th century 19世纪“宜居带”一词简史

IF 1.7 4区物理与天体物理

International Journal of Astrobiology Pub Date : 2021-06-25 DOI: 10.1017/s1473550421000203

M. Lingam

引用次数: 2

Conceptual discussion around the notion of the human being as an inter and multiplanetary species 围绕人类作为跨行星和多行星物种的概念进行概念性讨论

IF 1.7 4区物理与天体物理

International Journal of Astrobiology Pub Date : 2021-06-22 DOI: 10.1017/s1473550421000197

Octavio A. Chon-Torres, C. Murga-Moreno

引用次数: 0

Communicating extraterrestrial intelligence (CETI) interaction models based on the Drake equation 基于德雷克方程的交流地外智能(CETI)相互作用模型

IF 1.7 4区物理与天体物理

International Journal of Astrobiology Pub Date : 2021-06-19 DOI: 10.1017/S1473550422000404

Reginald D. Smith

引用次数: 1

The Noonday argument: fine-graining, indexicals, and the nature of Copernican reasoning 正午论证:细粒度、指数和哥白尼推理的本质

IF 1.7 4区物理与天体物理

International Journal of Astrobiology Pub Date : 2021-06-14 DOI: 10.1017/S1473550423000071

B. Lacki

{"title":"The Noonday argument: fine-graining, indexicals, and the nature of Copernican reasoning","authors":"B. Lacki","doi":"10.1017/S1473550423000071","DOIUrl":"https://doi.org/10.1017/S1473550423000071","url":null,"abstract":"\u0000 Typicality arguments attempt to use the Copernican Principle to draw conclusions about the cosmos and presently unknown conscious beings within it, including extraterrestrial intelligences (ETI). The most notorious is the Doomsday Argument, which purports to constrain humanity's future from its current lifespan alone. These arguments rest on a likelihood calculation that penalizes models in proportion to the number of distinguishable observers. I argue that such reasoning leads to solipsism, the belief that one is the only being in the world, and is therefore unacceptable. Using variants of the ‘Sleeping Beauty’ thought experiment as a guide, I present a framework for evaluating observations in a large cosmos: Weighted Fine Graining (WFG). WFG requires the construction of specific models of physical outcomes and observations. Valid typicality arguments then emerge from the combinatorial properties of third-person physical microhypotheses. Indexical (observer-relative) facts do not directly constrain physical theories, but instead weight different provisional evaluations of credence. As indexical knowledge changes, the weights shift. I show that the self-applied Doomsday Argument fails in WFG, even though it can work for an external observer. I argue that the Copernican Principle does not let us apply self-observations to constrain ETIs.","PeriodicalId":13879,"journal":{"name":"International Journal of Astrobiology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2021-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46799304","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}

引用次数: 1

Galactic traversability: a new concept for extragalactic SETI 星系可穿越性：河外SETI的一个新概念

IF 1.7 4区物理与天体物理

International Journal of Astrobiology Pub Date : 2021-06-14 DOI: 10.1017/S1473550421000252

B. Lacki

引用次数: 1

Presence of water on exomoons orbiting free-floating planets: a case study 绕自由漂浮行星运行的外卫星上水的存在：一个案例研究

IF 1.7 4区物理与天体物理

International Journal of Astrobiology Pub Date : 2021-06-08 DOI: 10.1017/S1473550421000173

P. Ávila, T. Grassi, S. Bovino, A. Chiavassa, B. Ercolano, S. Danielache, E. Simoncini

引用次数: 7

Mars: a free planet? 火星:一个自由的星球?

IF 1.7 4区物理与天体物理

International Journal of Astrobiology Pub Date : 2021-06-07 DOI: 10.1017/S1473550421000161

Octavio A. Chon-Torres

引用次数: 0

Complex structures synthesized in shock processing of nucleobases – implications to the origins of life 核碱基冲击加工合成的复杂结构——对生命起源的启示

IF 1.7 4区物理与天体物理

International Journal of Astrobiology Pub Date : 2021-05-26 DOI: 10.1017/S1473550421000136

V. Surendra, V. Jayaram, M. Muruganantham, T. Vijay, S. Vijayan, P. Samarth, H. Hill, A. Bhardwaj, N. Mason, B. Sivaraman

{"title":"Complex structures synthesized in shock processing of nucleobases – implications to the origins of life","authors":"V. Surendra, V. Jayaram, M. Muruganantham, T. Vijay, S. Vijayan, P. Samarth, H. Hill, A. Bhardwaj, N. Mason, B. Sivaraman","doi":"10.1017/S1473550421000136","DOIUrl":"https://doi.org/10.1017/S1473550421000136","url":null,"abstract":"\u0000 Nucleobases are nitrogenous bases composed of monomers that are a major constituent of RNA and DNA, which are an essential part of any cellular life on the Earth. The search for nucleobases in the interstellar medium remains a major challenge, however, the recent detection of nucleobases in meteorite samples and laboratory synthesis in simulated analogue experiments have confirmed their abiotic origin and a possible route for their delivery to the Earth. Nevertheless, cellular life is based on the interacting network of complex structures, and there is substantial lack of information on the possible routes by which such ordered structures may be formed in the prebiotic environment. In the current study, we present the evidence for the synthesis of complex structures due to shock processing of nucleobases. The nucleobases were subjected to the reflected shock temperature of 3500–7000 K (estimated) and pressure of about 15–34 bar for over ~2 ms timescale. Under such extreme thermodynamic conditions, the nucleobases sample experiences superheating and subsequent cooling. Electron microscopic studies of shock processed residue show that nucleobases result in spontaneous formation of complex structures when subjected to extreme conditions of shock. These results suggest that impact shock processes might have contributed to the self-assembly of biologically relevant structures and the origin of life.","PeriodicalId":13879,"journal":{"name":"International Journal of Astrobiology","volume":"1 1","pages":"1-9"},"PeriodicalIF":1.7,"publicationDate":"2021-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S1473550421000136","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49141510","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}

引用次数: 2

Humanity should colonize space in order to survive but not with embryo space colonization 人类应该在太空殖民以生存，而不是在胚胎太空殖民

IF 1.7 4区物理与天体物理

International Journal of Astrobiology Pub Date : 2021-05-25 DOI: 10.1017/S1473550421000148

K. Szocik

引用次数: 6