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Höning D, Spohn T. Land Fraction Diversity on Earth-like Planets and Implications for Their Habitability. ASTROBIOLOGY 2023; 23:372-394. [PMID: 36848252 DOI: 10.1089/ast.2022.0070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
A balanced ratio of ocean to land is believed to be essential for an Earth-like biosphere, and one may conjecture that plate-tectonics planets should be similar in geological properties. After all, the volume of continental crust evolves toward an equilibrium between production and erosion. If the interior thermal states of Earth-sized exoplanets are similar to those of Earth-a straightforward assumption due to the temperature dependence of mantle viscosity-one might expect a similar equilibrium between continental production and erosion to establish, and hence a similar land fraction. We show that this conjecture is not likely to be true. Positive feedback associated with the coupled mantle water-continental crust cycle may rather lead to a manifold of three possible planets, depending on their early history: a land planet, an ocean planet, and a balanced Earth-like planet. In addition, thermal blanketing of the interior by the continents enhances the sensitivity of continental growth to its history and, eventually, to initial conditions. Much of the blanketing effect is, however, compensated by mantle depletion in radioactive elements. A model of the long-term carbonate-silicate cycle shows the land and the ocean planets to differ by about 5 K in average surface temperature. A larger continental surface fraction results both in higher weathering rates and enhanced outgassing, partly compensating each other. Still, the land planet is expected to have a substantially dryer, colder, and harsher climate possibly with extended cold deserts in comparison with the ocean planet and with the present-day Earth. Using a model of balancing water availability and nutrients from continental crust weathering, we find the bioproductivity and the biomass of both the land and ocean planets to be reduced by a third to half of those of Earth. The biosphere on these planets might not be substantial enough to produce a supply of free oxygen.
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Affiliation(s)
- Dennis Höning
- Potsdam-Institute for Climate Impact Research, Potsdam, Germany
| | - Tilman Spohn
- International Space Science Institute, Bern, Switzerland
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2
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Way MJ, Ostberg C, Foley BJ, Gillmann C, Höning D, Lammer H, O’Rourke J, Persson M, Plesa AC, Salvador A, Scherf M, Weller M. Synergies Between Venus & Exoplanetary Observations: Venus and Its Extrasolar Siblings. SPACE SCIENCE REVIEWS 2023; 219:13. [PMID: 36785654 PMCID: PMC9911515 DOI: 10.1007/s11214-023-00953-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 01/11/2023] [Indexed: 06/18/2023]
Abstract
Here we examine how our knowledge of present day Venus can inform terrestrial exoplanetary science and how exoplanetary science can inform our study of Venus. In a superficial way the contrasts in knowledge appear stark. We have been looking at Venus for millennia and studying it via telescopic observations for centuries. Spacecraft observations began with Mariner 2 in 1962 when we confirmed that Venus was a hothouse planet, rather than the tropical paradise science fiction pictured. As long as our level of exploration and understanding of Venus remains far below that of Mars, major questions will endure. On the other hand, exoplanetary science has grown leaps and bounds since the discovery of Pegasus 51b in 1995, not too long after the golden years of Venus spacecraft missions came to an end with the Magellan Mission in 1994. Multi-million to billion dollar/euro exoplanet focused spacecraft missions such as JWST, and its successors will be flown in the coming decades. At the same time, excitement about Venus exploration is blooming again with a number of confirmed and proposed missions in the coming decades from India, Russia, Japan, the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA). Here we review what is known and what we may discover tomorrow in complementary studies of Venus and its exoplanetary cousins.
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Affiliation(s)
- M. J. Way
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025 USA
- Theoretical Astrophysics, Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
| | - Colby Ostberg
- Department of Earth and Planetary Sciences, University of California, Riverside, CA 92521 USA
| | - Bradford J. Foley
- Department of Geosciences, Pennsylvania State University, University Park, PA USA
| | - Cedric Gillmann
- Department of Earth, Environmental and Planetary Sciences, Rice University, Houston, TX 77005 USA
| | - Dennis Höning
- Potsdam Institute for Climate Impact Research, Potsdam, Germany
- Department of Earth Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Helmut Lammer
- Space Research Institute, Austrian Academy of Sciences, Schmiedlstr. 6, 8042 Graz, Austria
| | - Joseph O’Rourke
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ USA
| | - Moa Persson
- Institut de Recherche en Astrophysique et Planétologie, Centre National de la Recherche Scientifique, Université Paul Sabatier – Toulouse III, Centre National d’Etudes Spatiales, Toulouse, France
| | | | - Arnaud Salvador
- Department of Astronomy and Planetary Science, Northern Arizona University, Box 6010, Flagstaff, AZ 86011 USA
- Habitability, Atmospheres, and Biosignatures Laboratory, University of Arizona, Tucson, AZ USA
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ USA
| | - Manuel Scherf
- Space Research Institute, Austrian Academy of Sciences, Schmiedlstr. 6, 8042 Graz, Austria
- Institute of Physics, University of Graz, Graz, Austria
- Institute for Geodesy, Technical University, Graz, Austria
| | - Matthew Weller
- Lunar and Planetary Institute, 3600 Bay Area Blvd., Houston, TX 77058 USA
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3
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Gebauer S, Grenfell JL, Lammer H, de Vera JPP, Sproß L, Airapetian VS, Sinnhuber M, Rauer H. Atmospheric Nitrogen When Life Evolved on Earth. ASTROBIOLOGY 2020; 20:1413-1426. [PMID: 33121251 DOI: 10.1089/ast.2019.2212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The amount of nitrogen (N2) present in the atmosphere when life evolved on our planet is central for understanding the production of prebiotic molecules and, hence, is a fundamental quantity to constrain. Estimates of atmospheric molecular nitrogen partial surface pressures during the Archean, however, widely vary in the literature. In this study, we apply a model that combines newly gained insights into atmospheric escape, magma ocean duration, and outgassing evolution. Results suggest <420 mbar surface molecular nitrogen at the time when life originated, which is much lower compared with estimates in previous works and hence could impact our understanding of the production rate of prebiotic molecules such as hydrogen cyanide. Our revised values provide new input for atmospheric chamber experiments that simulate prebiotic chemistry on the early Earth. Our results that assume negligible nitrogen escape rates are in agreement with research based on solidified gas bubbles and the oxidation of iron in micrometeorites at 2.7 Gyr ago, which suggest that the atmospheric pressure was probably less than half the present-day value. Our results contradict previous studies that assume N2 partial surface pressures during the Archean were higher than those observed today and suggest that, if the N2 partial pressure were low in the Archean, it would likely be low in the Hadean as well. Furthermore, our results imply a biogenic nitrogen fixation rate from 9 to 14 Teragram N2 per year (Tg N2/year), which is consistent with modern marine biofixation rates and, hence, indicate an oceanic origin of this fixation process.
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Affiliation(s)
- Stefanie Gebauer
- Institute for Planetary Research (PF), German Aerospace Centre (DLR), Berlin, Germany
| | - John Lee Grenfell
- Institute for Planetary Research (PF), German Aerospace Centre (DLR), Berlin, Germany
| | - Helmut Lammer
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | | | - Laurenz Sproß
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
- Institute for Physics, University of Graz, Graz, Austria
| | - Vladimir S Airapetian
- NASA Goddard Space Flight Center (GSFC), Greenbelt, Maryland, USA
- American University, NW Washington, District of Columbia, USA
| | - Miriam Sinnhuber
- Institute for Meteorology and Climate Research, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Heike Rauer
- Institute for Planetary Research (PF), German Aerospace Centre (DLR), Berlin, Germany
- Institute for Geological Sciences, Planetology and Remote Sensing, Freie Universität Berlin (FUB), Berlin, Germany
- Centre for Astronomy and Astrophysics, Technische Universität Berlin (TUB), Berlin, Germany
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4
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Osinski G, Cockell C, Pontefract A, Sapers H. The Role of Meteorite Impacts in the Origin of Life. ASTROBIOLOGY 2020; 20:1121-1149. [PMID: 32876492 PMCID: PMC7499892 DOI: 10.1089/ast.2019.2203] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The conditions, timing, and setting for the origin of life on Earth and whether life exists elsewhere in our solar system and beyond represent some of the most fundamental scientific questions of our time. Although the bombardment of planets and satellites by asteroids and comets has long been viewed as a destructive process that would have presented a barrier to the emergence of life and frustrated or extinguished life, we provide a comprehensive synthesis of data and observations on the beneficial role of impacts in a wide range of prebiotic and biological processes. In the context of previously proposed environments for the origin of life on Earth, we discuss how meteorite impacts can generate both subaerial and submarine hydrothermal vents, abundant hydrothermal-sedimentary settings, and impact analogues for volcanic pumice rafts and splash pools. Impact events can also deliver and/or generate many of the necessary chemical ingredients for life and catalytic substrates such as clays as well. The role that impact cratering plays in fracturing planetary crusts and its effects on deep subsurface habitats for life are also discussed. In summary, we propose that meteorite impact events are a fundamental geobiological process in planetary evolution that played an important role in the origin of life on Earth. We conclude with the recommendation that impact craters should be considered prime sites in the search for evidence of past life on Mars. Furthermore, unlike other geological processes such as volcanism or plate tectonics, impact cratering is ubiquitous on planetary bodies throughout the Universe and is independent of size, composition, and distance from the host star. Impact events thus provide a mechanism with the potential to generate habitable planets, moons, and asteroids throughout the Solar System and beyond.
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Affiliation(s)
- G.R. Osinski
- Institute for Earth and Space Exploration, University of Western Ontario, London, Canada
- Department of Earth Sciences, University of Western Ontario, London, Canada
- Address correspondence to: Dr. Gordon Osinski, Department of Earth Sciences, 1151 Richmond Street, University of Western Ontario, London ON, N6A 5B7, Canada
| | - C.S. Cockell
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK
| | - A. Pontefract
- Department of Biology, Georgetown University, Washington, DC, USA
| | - H.M. Sapers
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA
- Department of Earth Sciences, University of Southern California, Los Angeles, California, USA
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5
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Lammer H, Sproß L, Grenfell JL, Scherf M, Fossati L, Lendl M, Cubillos PE. The Role of N 2 as a Geo-Biosignature for the Detection and Characterization of Earth-like Habitats. ASTROBIOLOGY 2019; 19:927-950. [PMID: 31314591 DOI: 10.1089/ast.2018.1914] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Since the Archean, N2 has been a major atmospheric constituent in Earth's atmosphere. Nitrogen is an essential element in the building blocks of life; therefore, the geobiological nitrogen cycle is a fundamental factor in the long-term evolution of both Earth and Earth-like exoplanets. We discuss the development of Earth's N2 atmosphere since the planet's formation and its relation with the geobiological cycle. Then we suggest atmospheric evolution scenarios and their possible interaction with life-forms: first for a stagnant-lid anoxic world, second for a tectonically active anoxic world, and third for an oxidized tectonically active world. Furthermore, we discuss a possible demise of present Earth's biosphere and its effects on the atmosphere. Since life-forms are the most efficient means for recycling deposited nitrogen back into the atmosphere at present, they sustain its surface partial pressure at high levels. Also, the simultaneous presence of significant N2 and O2 is chemically incompatible in an atmosphere over geological timescales. Thus, we argue that an N2-dominated atmosphere in combination with O2 on Earth-like planets within circumstellar habitable zones can be considered as a geo-biosignature. Terrestrial planets with such atmospheres will have an operating tectonic regime connected with an aerobic biosphere, whereas other scenarios in most cases end up with a CO2-dominated atmosphere. We conclude with implications for the search for life on Earth-like exoplanets inside the habitable zones of M to K stars.
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Affiliation(s)
- Helmut Lammer
- 1Austrian Academy of Sciences, Space Research Institute, Graz, Austria
| | - Laurenz Sproß
- 1Austrian Academy of Sciences, Space Research Institute, Graz, Austria
- 2Institute of Physics, University of Graz, Graz, Austria
| | - John Lee Grenfell
- 3Department of Extrasolar Planets and Atmospheres, German Aerospace Center, Institute of Planetary Research, Berlin, Germany
| | - Manuel Scherf
- 1Austrian Academy of Sciences, Space Research Institute, Graz, Austria
| | - Luca Fossati
- 1Austrian Academy of Sciences, Space Research Institute, Graz, Austria
| | - Monika Lendl
- 1Austrian Academy of Sciences, Space Research Institute, Graz, Austria
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6
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Myers MR, King GM. Perchlorate-Coupled Carbon Monoxide (CO) Oxidation: Evidence for a Plausible Microbe-Mediated Reaction in Martian Brines. Front Microbiol 2017; 8:2571. [PMID: 29312249 PMCID: PMC5743682 DOI: 10.3389/fmicb.2017.02571] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 12/11/2017] [Indexed: 11/29/2022] Open
Abstract
The presence of hydrated salts on Mars indicates that some regions of its surface might be habitable if suitable metabolizable substrates are available. However, several lines of evidence have shown that Mars' regolith contains only trace levels of the organic matter needed to support heterotrophic microbes. Due to the scarcity of organic carbon, carbon monoxide (CO) at a concentration of about 700 parts per million (about 0.4 Pa) might be the single most abundant readily available substrate that could support near-surface bacterial activity. Although a variety of electron acceptors can be coupled to CO oxidation, perchlorate is likely the most abundant potential oxidant in Mars' brines. Whether perchlorate, a potent chaotrope, can support microbial CO oxidation has not been previously documented. We report here the first evidence for perchlorate-coupled CO oxidation based on assays with two distinct euryarchaeal extreme halophiles. CO oxidation occurred readily in 3.8 M NaCl brines with perchlorate concentrations from 0.01 to 1 M. Both isolates were able to couple CO with perchlorate or chlorate under anaerobic conditions with or without nitrate as an inducer for nitrate reductase, which serves as a perchlorate reductase in extreme halophiles. In the presence of perchlorate, CO concentrations were reduced to levels well below those found in Mars' atmosphere. This indicates that CO could contribute to the survival of microbial populations in hydrated salt formations or brines if water activities are suitably permissive.
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Affiliation(s)
| | - Gary M. King
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, United States
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7
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Foucher F, Hickman-Lewis K, Westall F, Brack A. A Statistical Approach to Illustrate the Challenge of Astrobiology for Public Outreach. Life (Basel) 2017; 7:life7040040. [PMID: 29072614 PMCID: PMC5745553 DOI: 10.3390/life7040040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 10/24/2017] [Accepted: 10/25/2017] [Indexed: 01/08/2023] Open
Abstract
In this study, we attempt to illustrate the competition that constitutes the main challenge of astrobiology, namely the competition between the probability of extraterrestrial life and its detectability. To illustrate this fact, we propose a simple statistical approach based on our knowledge of the Universe and the Milky Way, the Solar System, and the evolution of life on Earth permitting us to obtain the order of magnitude of the distance between Earth and bodies inhabited by more or less evolved past or present life forms, and the consequences of this probability for the detection of associated biosignatures. We thus show that the probability of the existence of evolved extraterrestrial forms of life increases with distance from the Earth while, at the same time, the number of detectable biosignatures decreases due to technical and physical limitations. This approach allows us to easily explain to the general public why it is very improbable to detect a signal of extraterrestrial intelligence while it is justified to launch space probes dedicated to the search for microbial life in the Solar System.
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Affiliation(s)
- Frédéric Foucher
- CNRS, Centre de Biophysique Moléculaire, UPR 4301, Rue Charles Sadron, CS80054, 45071 Orléans CEDEX, France.
| | - Keyron Hickman-Lewis
- CNRS, Centre de Biophysique Moléculaire, UPR 4301, Rue Charles Sadron, CS80054, 45071 Orléans CEDEX, France.
| | - Frances Westall
- CNRS, Centre de Biophysique Moléculaire, UPR 4301, Rue Charles Sadron, CS80054, 45071 Orléans CEDEX, France.
| | - André Brack
- CNRS, Centre de Biophysique Moléculaire, UPR 4301, Rue Charles Sadron, CS80054, 45071 Orléans CEDEX, France.
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8
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Carbon monoxide as a metabolic energy source for extremely halophilic microbes: implications for microbial activity in Mars regolith. Proc Natl Acad Sci U S A 2015; 112:4465-70. [PMID: 25831529 DOI: 10.1073/pnas.1424989112] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Carbon monoxide occurs at relatively high concentrations (≥800 parts per million) in Mars' atmosphere, where it represents a potentially significant energy source that could fuel metabolism by a localized putative surface or near-surface microbiota. However, the plausibility of CO oxidation under conditions relevant for Mars in its past or at present has not been evaluated. Results from diverse terrestrial brines and saline soils provide the first documentation, to our knowledge, of active CO uptake at water potentials (-41 MPa to -117 MPa) that might occur in putative brines at recurrent slope lineae (RSL) on Mars. Results from two extremely halophilic isolates complement the field observations. Halorubrum str. BV1, isolated from the Bonneville Salt Flats, Utah (to our knowledge, the first documented extremely halophilic CO-oxidizing member of the Euryarchaeota), consumed CO in a salt-saturated medium with a water potential of -39.6 MPa; activity was reduced by only 28% relative to activity at its optimum water potential of -11 MPa. A proteobacterial isolate from hypersaline Mono Lake, California, Alkalilimnicola ehrlichii MLHE-1, also oxidized CO at low water potentials (-19 MPa), at temperatures within ranges reported for RSL, and under oxic, suboxic (0.2% oxygen), and anoxic conditions (oxygen-free with nitrate). MLHE-1 was unaffected by magnesium perchlorate or low atmospheric pressure (10 mbar). These results collectively establish the potential for microbial CO oxidation under conditions that might obtain at local scales (e.g., RSL) on contemporary Mars and at larger spatial scales earlier in Mars' history.
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9
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Cady LP, Brack A, Bueno Prieto JE, Cockell C, Horneck G, Kasting JF, Lineweaver CH, Raulin F, Schopf JW, Sleep N, von Bloh W, Westall F, Deamer D, Lehman N, Pérez-Mercader J. Where do we go from here? Astrobiology editorial board opinions. ASTROBIOLOGY 2014; 14:629-644. [PMID: 25102138 DOI: 10.1089/ast.2014.1405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
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10
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Ruiz-Mirazo K, Briones C, de la Escosura A. Prebiotic Systems Chemistry: New Perspectives for the Origins of Life. Chem Rev 2013; 114:285-366. [DOI: 10.1021/cr2004844] [Citation(s) in RCA: 563] [Impact Index Per Article: 51.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Kepa Ruiz-Mirazo
- Biophysics
Unit (CSIC-UPV/EHU), Leioa, and Department of Logic and Philosophy
of Science, University of the Basque Country, Avenida de Tolosa 70, 20080 Donostia−San Sebastián, Spain
| | - Carlos Briones
- Department
of Molecular Evolution, Centro de Astrobiología (CSIC−INTA, associated to the NASA Astrobiology Institute), Carretera de Ajalvir, Km 4, 28850 Torrejón de Ardoz, Madrid, Spain
| | - Andrés de la Escosura
- Organic
Chemistry Department, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
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11
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Spitzer J. Emergence of life from multicomponent mixtures of chemicals: the case for experiments with cycling physicochemical gradients. ASTROBIOLOGY 2013; 13:404-413. [PMID: 23577817 DOI: 10.1089/ast.2012.0924] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The emergence of life from planetary multicomponent mixtures of chemicals is arguably the most complicated and least understood natural phenomenon. The fact that living cells are non-equilibrium systems suggests that life can emerge only from non-equilibrium chemical systems. From an astrobiological standpoint, non-equilibrium chemical systems arise naturally when solar irradiation strikes rotating surfaces of habitable planets: the resulting cycling physicochemical gradients persistently drive planetary chemistries toward "embryonic" living systems and an eventual emergence of life. To better understand the factors that lead to the emergence of life, I argue for cycling non-equilibrium experiments with multicomponent chemical systems designed to represent the evolving chemistry of Hadean Earth ("prebiotic soups"). Specifically, I suggest experimentation with chemical engineering simulators of Hadean Earth to observe and analyze (i) the appearances and phase separations of surface active and polymeric materials as precursors of the first "cell envelopes" (membranes) and (ii) the accumulations, commingling, and co-reactivity of chemicals from atmospheric, oceanic, and terrestrial locations.
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Affiliation(s)
- Jan Spitzer
- R&D Department, MCP Inc., Charlotte, North Carolina 29262, USA.
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12
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Abstract
Ionizing radiation is a ubiquitous feature of the Cosmos, from exogenous cosmic rays (CR) to the intrinsic mineral radioactivity of a habitable world, and its influences on the emergence and persistence of life are wide-ranging and profound. Much attention has already been focused on the deleterious effects of ionizing radiation on organisms and the complex molecules of life, but ionizing radiation also performs many crucial functions in the generation of habitable planetary environments and the origins of life. This review surveys the role of CR and mineral radioactivity in star formation, generation of biogenic elements, and the synthesis of organic molecules and driving of prebiotic chemistry. Another major theme is the multiple layers of shielding of planetary surfaces from the flux of cosmic radiation and the various effects on a biosphere of violent but rare astrophysical events such as supernovae and gamma-ray bursts. The influences of CR can also be duplicitous, such as limiting the survival of surface life on Mars while potentially supporting a subsurface biosphere in the ocean of Europa. This review highlights the common thread that ionizing radiation forms between the disparate component disciplines of astrobiology.
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Affiliation(s)
- Lewis R Dartnell
- UCL Institute for Origins, University College London, London, UK.
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13
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Tessera M. Origin of evolution versus origin of life: a shift of paradigm. Int J Mol Sci 2011; 12:3445-58. [PMID: 21747687 PMCID: PMC3131571 DOI: 10.3390/ijms12063445] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 05/24/2011] [Accepted: 05/25/2011] [Indexed: 11/26/2022] Open
Abstract
The question of the primordial ancestor must be approached through the search for the origin of evolution, not through the search for the origin of life. There is a major issue with the concept of life because it is impossible to define, thus is not a scientific but a metaphysical concept. On the contrary, evolution may be defined by as few as three conditions. These do not necessarily involve biopolymers. However, such an approach must give clues to explain the emergence of distinct lineages to allow Darwinian natural selection. A plausible solution exists within an autotrophic lipidic vesicle-based model that is presented. The model requires the existence of hydrothermal sites such as the Lost City Hydrothermal Field leading to specific constraints. For this reason Mars and Europa may be questioned as possible cradles of evolution. If we replace the search for the origin of life by the one for the origin of evolution our priority first is to find a consensus on the minimal conditions that would allow evolution to emerge and persist anywhere in the universe.
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Affiliation(s)
- Marc Tessera
- 2 Avenue du 11 Novembre 1918, Meudon 92190, France; E-Mail: ; Tel.: +33-6-86-46-60-94
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14
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Brack A. From the love of peptides to the search for life on Mars, an astrobiology itinerary. ASTROBIOLOGY 2011; 11:275-279. [PMID: 21545269 DOI: 10.1089/ast.2011.0616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Affiliation(s)
- André Brack
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique, Orléans, France.
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15
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Fridlund M, Lammer H. The astrobiology habitability primer. ASTROBIOLOGY 2010; 10:1-4. [PMID: 20307178 DOI: 10.1089/ast.2009.0382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Affiliation(s)
- Malcolm Fridlund
- Research and Scientific Support Department, ESA, European Space Research and Technology Centre, Noordwijk, the Netherlands.
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