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Tosi F, Roatsch T, Galli A, Hauber E, Lucchetti A, Molyneux P, Stephan K, Achilleos N, Bovolo F, Carter J, Cavalié T, Cimò G, D’Aversa E, Gwinner K, Hartogh P, Huybrighs H, Langevin Y, Lellouch E, Migliorini A, Palumbo P, Piccioni G, Plaut JJ, Postberg F, Poulet F, Retherford K, Rezac L, Roth L, Solomonidou A, Tobie G, Tortora P, Tubiana C, Wagner R, Wirström E, Wurz P, Zambon F, Zannoni M, Barabash S, Bruzzone L, Dougherty M, Gladstone R, Gurvits LI, Hussmann H, Iess L, Wahlund JE, Witasse O, Vallat C, Lorente R. Characterization of the Surfaces and Near-Surface Atmospheres of Ganymede, Europa and Callisto by JUICE. SPACE SCIENCE REVIEWS 2024; 220:59. [PMID: 39132056 PMCID: PMC11310297 DOI: 10.1007/s11214-024-01089-8] [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: 07/14/2023] [Accepted: 07/01/2024] [Indexed: 08/13/2024]
Abstract
We present the state of the art on the study of surfaces and tenuous atmospheres of the icy Galilean satellites Ganymede, Europa and Callisto, from past and ongoing space exploration conducted with several spacecraft to recent telescopic observations, and we show how the ESA JUICE mission plans to explore these surfaces and atmospheres in detail with its scientific payload. The surface geology of the moons is the main evidence of their evolution and reflects the internal heating provided by tidal interactions. Surface composition is the result of endogenous and exogenous processes, with the former providing valuable information about the potential composition of shallow subsurface liquid pockets, possibly connected to deeper oceans. Finally, the icy Galilean moons have tenuous atmospheres that arise from charged particle sputtering affecting their surfaces. In the case of Europa, plumes of water vapour have also been reported, whose phenomenology at present is poorly understood and requires future close exploration. In the three main sections of the article, we discuss these topics, highlighting the key scientific objectives and investigations to be achieved by JUICE. Based on a recent predicted trajectory, we also show potential coverage maps and other examples of reference measurements. The scientific discussion and observation planning presented here are the outcome of the JUICE Working Group 2 (WG2): "Surfaces and Near-surface Exospheres of the Satellites, dust and rings".
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Affiliation(s)
- Federico Tosi
- Istituto Nazionale di Astrofisica – Istituto di Astrofisica e Planetologia Spaziali (INAF-IAPS), Rome, Italy
| | - Thomas Roatsch
- Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany
| | - André Galli
- Physics Institute, Space Research and Planetary Sciences, University of Bern, Bern, Switzerland
| | - Ernst Hauber
- Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany
| | - Alice Lucchetti
- Istituto Nazionale di Astrofisica – Osservatorio Astronomico di Padova (INAF-OAPd), Padua, Italy
| | | | - Katrin Stephan
- Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany
| | - Nicholas Achilleos
- Department of Physics & Astronomy, University College London, London, UK
| | - Francesca Bovolo
- Center for Digital Society, Fondazione Bruno Kessler (FBK), Trento, Italy
| | - John Carter
- Institut d’Astrophysique Spatiale (IAS), CNRS/Université Paris-Saclay, Orsay, France
| | - Thibault Cavalié
- Laboratoire d’Astrophysique de Bordeaux, Université de Bordeaux, CNRS, Pessac, France
- LESIA, Observatoire de Paris, Meudon, France
| | - Giuseppe Cimò
- Joint Institute for VLBI ERIC, Dwingeloo, The Netherlands
| | - Emiliano D’Aversa
- Istituto Nazionale di Astrofisica – Istituto di Astrofisica e Planetologia Spaziali (INAF-IAPS), Rome, Italy
| | - Klaus Gwinner
- Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany
| | - Paul Hartogh
- Max Planck Institute for Solar System Research, Göttingen, Germany
| | - Hans Huybrighs
- Space and Planetary Science Center, Khalifa University, Abu Dhabi, UAE
- School of Cosmic Physics, Dunsink Observatory, Dublin Institute for Advanced Studies (DIAS), Dublin, Ireland
| | - Yves Langevin
- Institut d’Astrophysique Spatiale (IAS), CNRS/Université Paris-Saclay, Orsay, France
| | | | - Alessandra Migliorini
- Istituto Nazionale di Astrofisica – Istituto di Astrofisica e Planetologia Spaziali (INAF-IAPS), Rome, Italy
| | - Pasquale Palumbo
- Istituto Nazionale di Astrofisica – Istituto di Astrofisica e Planetologia Spaziali (INAF-IAPS), Rome, Italy
| | - Giuseppe Piccioni
- Istituto Nazionale di Astrofisica – Istituto di Astrofisica e Planetologia Spaziali (INAF-IAPS), Rome, Italy
| | | | - Frank Postberg
- Department of Earth Sciences, Freie Universität Berlin, Berlin, Germany
| | - François Poulet
- Institut d’Astrophysique Spatiale (IAS), CNRS/Université Paris-Saclay, Orsay, France
| | | | - Ladislav Rezac
- Max Planck Institute for Solar System Research, Göttingen, Germany
| | - Lorenz Roth
- Division of Space and Plasma Physics, KTH Royal Institute of Technology, Stockholm, Sweden
| | | | - Gabriel Tobie
- Laboratoire de Planétologie et Géosciences, Nantes Université, Nantes, France
| | - Paolo Tortora
- Department of Industrial Engineering (DIN), Università di Bologna, Forlì, Italy
| | - Cecilia Tubiana
- Istituto Nazionale di Astrofisica – Istituto di Astrofisica e Planetologia Spaziali (INAF-IAPS), Rome, Italy
| | - Roland Wagner
- Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany
| | - Eva Wirström
- Chalmers University of Technology, Onsala, Sweden
| | - Peter Wurz
- Physics Institute, Space Research and Planetary Sciences, University of Bern, Bern, Switzerland
| | - Francesca Zambon
- Istituto Nazionale di Astrofisica – Istituto di Astrofisica e Planetologia Spaziali (INAF-IAPS), Rome, Italy
| | - Marco Zannoni
- Department of Industrial Engineering (DIN), Università di Bologna, Forlì, Italy
| | | | - Lorenzo Bruzzone
- Dipartimento di Ingegneria e Scienza dell’Informazione, Università degli Studi di Trento, Trento, Italy
| | | | | | - Leonid I. Gurvits
- Joint Institute for VLBI ERIC, Dwingeloo, The Netherlands
- Faculty of Aerospace Engineering, Delft University of Technology, Delft, The Netherlands
| | - Hauke Hussmann
- Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany
| | - Luciano Iess
- Dipartimento di Ingegneria Meccanica e Aerospaziale (DIMA), Università degli Studi di Roma “La Sapienza”, Rome, Italy
| | | | - Olivier Witasse
- European Space Agency – European Space Research and Technology Centre (ESA-ESTEC), Noordwijk, The Netherlands
| | - Claire Vallat
- European Space Agency – European Space Astronomy Centre (ESA-ESAC), Madrid, Spain
| | - Rosario Lorente
- European Space Agency – European Space Astronomy Centre (ESA-ESAC), Madrid, Spain
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Blankenship DD, Moussessian A, Chapin E, Young DA, Wesley Patterson G, Plaut JJ, Freedman AP, Schroeder DM, Grima C, Steinbrügge G, Soderlund KM, Ray T, Richter TG, Jones-Wilson L, Wolfenbarger NS, Scanlan KM, Gerekos C, Chan K, Seker I, Haynes MS, Barr Mlinar AC, Bruzzone L, Campbell BA, Carter LM, Elachi C, Gim Y, Hérique A, Hussmann H, Kofman W, Kurth WS, Mastrogiuseppe M, McKinnon WB, Moore JM, Nimmo F, Paty C, Plettemeier D, Schmidt BE, Zolotov MY, Schenk PM, Collins S, Figueroa H, Fischman M, Tardiff E, Berkun A, Paller M, Hoffman JP, Kurum A, Sadowy GA, Wheeler KB, Decrossas E, Hussein Y, Jin C, Boldissar F, Chamberlain N, Hernandez B, Maghsoudi E, Mihaly J, Worel S, Singh V, Pak K, Tanabe J, Johnson R, Ashtijou M, Alemu T, Burke M, Custodero B, Tope MC, Hawkins D, Aaron K, Delory GT, Turin PS, Kirchner DL, Srinivasan K, Xie J, Ortloff B, Tan I, Noh T, Clark D, Duong V, Joshi S, Lee J, Merida E, Akbar R, Duan X, Fenni I, Sanchez-Barbetty M, Parashare C, Howard DC, Newman J, Cruz MG, Barabas NJ, Amirahmadi A, Palmer B, Gawande RS, Milroy G, Roberti R, Leader FE, West RD, Martin J, Venkatesh V, Adumitroaie V, Rains C, Quach C, Turner JE, O’Shea CM, Kempf SD, Ng G, Buhl DP, Urban TJ. Radar for Europa Assessment and Sounding: Ocean to Near-Surface (REASON). SPACE SCIENCE REVIEWS 2024; 220:51. [PMID: 38948073 PMCID: PMC11211191 DOI: 10.1007/s11214-024-01072-3] [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: 08/01/2023] [Accepted: 04/29/2024] [Indexed: 07/02/2024]
Abstract
The Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON) is a dual-frequency ice-penetrating radar (9 and 60 MHz) onboard the Europa Clipper mission. REASON is designed to probe Europa from exosphere to subsurface ocean, contributing the third dimension to observations of this enigmatic world. The hypotheses REASON will test are that (1) the ice shell of Europa hosts liquid water, (2) the ice shell overlies an ocean and is subject to tidal flexing, and (3) the exosphere, near-surface, ice shell, and ocean participate in material exchange essential to the habitability of this moon. REASON will investigate processes governing this material exchange by characterizing the distribution of putative non-ice material (e.g., brines, salts) in the subsurface, searching for an ice-ocean interface, characterizing the ice shell's global structure, and constraining the amplitude of Europa's radial tidal deformations. REASON will accomplish these science objectives using a combination of radar measurement techniques including altimetry, reflectometry, sounding, interferometry, plasma characterization, and ranging. Building on a rich heritage from Earth, the moon, and Mars, REASON will be the first ice-penetrating radar to explore the outer solar system. Because these radars are untested for the icy worlds in the outer solar system, a novel approach to measurement quality assessment was developed to represent uncertainties in key properties of Europa that affect REASON performance and ensure robustness across a range of plausible parameters suggested for the icy moon. REASON will shed light on a never-before-seen dimension of Europa and - in concert with other instruments on Europa Clipper - help to investigate whether Europa is a habitable world.
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Affiliation(s)
| | - Alina Moussessian
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Elaine Chapin
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Duncan A. Young
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
| | | | - Jeffrey J. Plaut
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Adam P. Freedman
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Dustin M. Schroeder
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305 USA
- Department of Geophysics, Stanford University, Stanford, CA 94305 USA
| | - Cyril Grima
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
| | - Gregor Steinbrügge
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Krista M. Soderlund
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
| | - Trina Ray
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Thomas G. Richter
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
| | - Laura Jones-Wilson
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | | | - Kirk M. Scanlan
- Geodesy & Earth Observation Division, DTU Space, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Christopher Gerekos
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
| | - Kristian Chan
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
- Department of Earth and Planetary Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78712 USA
| | - Ilgin Seker
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Mark S. Haynes
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | | | | | - Bruce A. Campbell
- Smithsonian Institution, Center for Earth & Planetary Studies, MRC 315, Washington, DC 20013-7012 USA
| | - Lynn M. Carter
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 USA
| | - Charles Elachi
- California Institute of Technology, Pasadena, CA 91125 USA
| | - Yonggyu Gim
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Alain Hérique
- University Grenoble Alpes, CNRS, CNES, IPAG, 38000 Grenoble, France
| | - Hauke Hussmann
- Institute of Planetary Research, German Aerospace Center, Berlin, Germany
| | - Wlodek Kofman
- University Grenoble Alpes, CNRS, CNES, IPAG, 38000 Grenoble, France
- Centrum Badan Kosmicznych Polskiej Akademii Nauk (CBK PAN), Warsaw, Poland
| | - William S. Kurth
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 USA
| | | | | | | | - Francis Nimmo
- Dept. Earth and Planetary Sciences, University of California, Santa Cruz, CA 95064 USA
| | - Carol Paty
- Department of Earth Sciences, University of Oregon, Eugene, OR 97403 USA
| | | | - Britney E. Schmidt
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY USA
- Department of Astronomy, Cornell University, Ithaca, NY USA
| | - Mikhail Y. Zolotov
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 USA
| | | | - Simon Collins
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Harry Figueroa
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Mark Fischman
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Eric Tardiff
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Andy Berkun
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Mimi Paller
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | | | | | - Gregory A. Sadowy
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Kevin B. Wheeler
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Emmanuel Decrossas
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Yasser Hussein
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Curtis Jin
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Frank Boldissar
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Neil Chamberlain
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Brenda Hernandez
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Elham Maghsoudi
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Jonathan Mihaly
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303 USA
| | - Shana Worel
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Vik Singh
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Kyung Pak
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Jordan Tanabe
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Robert Johnson
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Mohammad Ashtijou
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Tafesse Alemu
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Michael Burke
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Brian Custodero
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Michael C. Tope
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - David Hawkins
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Kim Aaron
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | | | | | - Donald L. Kirchner
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 USA
| | - Karthik Srinivasan
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Julie Xie
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Brad Ortloff
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Ian Tan
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Tim Noh
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Duane Clark
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Vu Duong
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Shivani Joshi
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Jeng Lee
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Elvis Merida
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Ruzbeh Akbar
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Xueyang Duan
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Ines Fenni
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | | | - Chaitali Parashare
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Duane C. Howard
- Center for Quantum Computing, Amazon Web Services, Pasadena, CA 91125 USA
| | | | - Marvin G. Cruz
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | | | - Ahmadreza Amirahmadi
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Brendon Palmer
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Rohit S. Gawande
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Grace Milroy
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Rick Roberti
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Frank E. Leader
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Richard D. West
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Jan Martin
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Vijay Venkatesh
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Virgil Adumitroaie
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Christine Rains
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Cuong Quach
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Jordi E. Turner
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723 USA
| | - Colleen M. O’Shea
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723 USA
| | - Scott D. Kempf
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
| | - Gregory Ng
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
| | - Dillon P. Buhl
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
| | - Timothy J. Urban
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
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3
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Styczinski MJ, Cooper ZS, Glaser DM, Lehmer O, Mierzejewski V, Tarnas J. Chapter 7: Assessing Habitability Beyond Earth. ASTROBIOLOGY 2024; 24:S143-S163. [PMID: 38498826 DOI: 10.1089/ast.2021.0097] [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: 03/20/2024]
Abstract
All known life on Earth inhabits environments that maintain conditions between certain extremes of temperature, chemical composition, energy availability, and so on (Chapter 6). Life may have emerged in similar environments elsewhere in the Solar System and beyond. The ongoing search for life elsewhere mainly focuses on those environments most likely to support life, now or in the past-that is, potentially habitable environments. Discussion of habitability is necessarily based on what we know about life on Earth, as it is our only example. This chapter gives an overview of the known and presumed requirements for life on Earth and discusses how these requirements can be used to assess the potential habitability of planetary bodies across the Solar System and beyond. We first consider the chemical requirements of life and potential feedback effects that the presence of life can have on habitable conditions, and then the planetary, stellar, and temporal requirements for habitability. We then review the state of knowledge on the potential habitability of bodies across the Solar System and exoplanets, with a particular focus on Mars, Venus, Europa, and Enceladus. While reviewing the case for the potential habitability of each body, we summarize the most prominent and impactful studies that have informed the perspective on where habitable environments are likely to be found.
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Affiliation(s)
- M J Styczinski
- University of Washington, Seattle, Washington, USA
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Z S Cooper
- University of Washington, Seattle, Washington, USA
| | - D M Glaser
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA
| | - O Lehmer
- NASA Ames Research Center, Moffett Field, California, USA
| | - V Mierzejewski
- School of Earth and Space Exploration, Arizona State University, Arizona, USA
| | - J Tarnas
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
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4
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Vance SD, Craft KL, Shock E, Schmidt BE, Lunine J, Hand KP, McKinnon WB, Spiers EM, Chivers C, Lawrence JD, Wolfenbarger N, Leonard EJ, Robinson KJ, Styczinski MJ, Persaud DM, Steinbrügge G, Zolotov MY, Quick LC, Scully JEC, Becker TM, Howell SM, Clark RN, Dombard AJ, Glein CR, Mousis O, Sephton MA, Castillo-Rogez J, Nimmo F, McEwen AS, Gudipati MS, Jun I, Jia X, Postberg F, Soderlund KM, Elder CM. Investigating Europa's Habitability with the Europa Clipper. SPACE SCIENCE REVIEWS 2023; 219:81. [PMID: 38046182 PMCID: PMC10687213 DOI: 10.1007/s11214-023-01025-2] [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: 10/22/2022] [Accepted: 11/03/2023] [Indexed: 12/05/2023]
Abstract
The habitability of Europa is a property within a system, which is driven by a multitude of physical and chemical processes and is defined by many interdependent parameters, so that its full characterization requires collaborative investigation. To explore Europa as an integrated system to yield a complete picture of its habitability, the Europa Clipper mission has three primary science objectives: (1) characterize the ice shell and ocean including their heterogeneity, properties, and the nature of surface-ice-ocean exchange; (2) characterize Europa's composition including any non-ice materials on the surface and in the atmosphere, and any carbon-containing compounds; and (3) characterize Europa's geology including surface features and localities of high science interest. The mission will also address several cross-cutting science topics including the search for any current or recent activity in the form of thermal anomalies and plumes, performing geodetic and radiation measurements, and assessing high-resolution, co-located observations at select sites to provide reconnaissance for a potential future landed mission. Synthesizing the mission's science measurements, as well as incorporating remote observations by Earth-based observatories, the James Webb Space Telescope, and other space-based resources, to constrain Europa's habitability, is a complex task and is guided by the mission's Habitability Assessment Board (HAB).
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Affiliation(s)
- Steven D. Vance
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - Kathleen L. Craft
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD USA
| | - Everett Shock
- School of Earth & Space Exploration and School of Molecular Sciences, Arizona State University, Tempe, AZ USA
| | - Britney E. Schmidt
- Department of Astronomy and Department of Earth & Atmospheric Sciences, Cornell University, Ithaca, NY USA
| | - Jonathan Lunine
- Department of Astronomy and Department of Earth & Atmospheric Sciences, Cornell University, Ithaca, NY USA
| | - Kevin P. Hand
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - William B. McKinnon
- Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University in St. Louis, Saint Louis, MO USA
| | - Elizabeth M. Spiers
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA USA
| | - Chase Chivers
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA USA
- Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, Woods Hole, MA USA
| | - Justin D. Lawrence
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA USA
- Honeybee Robotics, Altadena, CA USA
| | - Natalie Wolfenbarger
- Institute for Geophysics, John A. and Katherine G. Jackson School of Geosciences, University of Texas at Austin, Austin, TX USA
| | - Erin J. Leonard
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | | | | | - Divya M. Persaud
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - Gregor Steinbrügge
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - Mikhail Y. Zolotov
- School of Earth & Space Exploration and School of Molecular Sciences, Arizona State University, Tempe, AZ USA
| | | | | | | | - Samuel M. Howell
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | | | - Andrew J. Dombard
- Dept. of Earth and Environmental Sciences, University of Illinois Chicago, Chicago, USA
| | | | - Olivier Mousis
- Aix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille), Marseille, France
| | - Mark A. Sephton
- Impacts and Astromaterials Research Centre, Department of Earth Science and Engineering, Imperial College London, London, United Kingdom
| | | | - Francis Nimmo
- Department of Earth and Planetary Sciences, University of California, Santa Cruz, CA USA
| | - Alfred S. McEwen
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ USA
| | - Murthy S. Gudipati
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - Insoo Jun
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - Xianzhe Jia
- Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI USA
| | - Frank Postberg
- Institut für Geologische Wissenschaften, Freie Universität Berlin, Berlin, Germany
| | - Krista M. Soderlund
- Institute for Geophysics, John A. and Katherine G. Jackson School of Geosciences, University of Texas at Austin, Austin, TX USA
| | - Catherine M. Elder
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
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5
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Seaton KM, Pozarycki CI, Nuñez N, Stockton AM. A Robust Capillary Electrophoresis with Laser-Induced Fluorescence Detection (CE-LIF) Method for Quantitative Compositional Analysis of Trace Amino Acids in Hypersaline Samples. ACS EARTH & SPACE CHEMISTRY 2023; 7:2214-2221. [PMID: 38026810 PMCID: PMC10658621 DOI: 10.1021/acsearthspacechem.3c00162] [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: 06/09/2023] [Revised: 09/20/2023] [Accepted: 09/28/2023] [Indexed: 12/01/2023]
Abstract
The search for life in our solar system can be enabled by the characterization of extreme environments representing conditions expected on other planets within our solar system. Molecular abundances observed in these environments help establish instrument design requirements, including limits of detection and pH/salt tolerance, and may be used for validation of proposed planetary science instrumentation. Here, we optimize capillary electrophoresis with laser-induced fluorescence detection (CE-LIF) separations for low limit of detection quantitative compositional analysis of amino acids in hypersaline samples using carboxyfluorescein succinimidyl ester (CFSE) as the amine-reactive fluorescent probe. Two methods were optimized for identification and quantification of proteinogenic amino acids, those with and those without acidic side chains, with limits of detection as low as 250 pM, improving on previous CFSE-amino acid CE-LIF methods by an order of magnitude. The resilience of the method to samples with high concentrations of Mg2+ (>4 M diluted to >0.4 M for analysis) is demonstrated on a sample collected from the salt harvesting facility South Bay Salt Works in San Diego, CA, demonstrating the highest Mg2+ tolerance for CE-LIF methods used in amino acid analyses to date. This advancement enables the rapid and robust analysis of trace amino acids and the search for biosignatures in hypersaline systems.
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Affiliation(s)
- K. Marshall Seaton
- School
of Chemistry & Biochemistry, Georgia
Institute of Technology, Atlanta, Georgia 30332, United States
| | - Chad I. Pozarycki
- School
of Chemistry & Biochemistry, Georgia
Institute of Technology, Atlanta, Georgia 30332, United States
| | - Nickie Nuñez
- School
of Chemistry & Biochemistry, Georgia
Institute of Technology, Atlanta, Georgia 30332, United States
| | - Amanda M. Stockton
- School
of Chemistry & Biochemistry, Georgia
Institute of Technology, Atlanta, Georgia 30332, United States
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6
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Villanueva GL, Hammel HB, Milam SN, Faggi S, Kofman V, Roth L, Hand KP, Paganini L, Stansberry J, Spencer J, Protopapa S, Strazzulla G, Cruz-Mermy G, Glein CR, Cartwright R, Liuzzi G. Endogenous CO 2 ice mixture on the surface of Europa and no detection of plume activity. Science 2023; 381:1305-1308. [PMID: 37733858 DOI: 10.1126/science.adg4270] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 08/22/2023] [Indexed: 09/23/2023]
Abstract
Jupiter's moon Europa has a subsurface ocean beneath an icy crust. Conditions within the ocean are unknown, and it is unclear whether it is connected to the surface. We observed Europa with the James Webb Space Telescope (JWST) to search for active release of material by probing its surface and atmosphere. A search for plumes yielded no detection of water, carbon monoxide, methanol, ethane, or methane fluorescence emissions. Four spectral features of carbon dioxide (CO2) ice were detected; their spectral shapes and distribution across Europa's surface indicate that the CO2 is mixed with other compounds and concentrated in Tara Regio. The 13CO2 absorption is consistent with an isotopic ratio of 12C/13C = 83 ± 19. We interpret these observations as indicating that carbon is sourced from within Europa.
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Affiliation(s)
- G L Villanueva
- NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - H B Hammel
- Association of Universities for Research in Astronomy, Washington, DC 20004, USA
| | - S N Milam
- NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - S Faggi
- NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
- American University, Washington, DC 20016, USA
| | - V Kofman
- NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
- American University, Washington, DC 20016, USA
| | - L Roth
- Royal Institute of Technology, Stockholm 104 50, Sweden
| | - K P Hand
- Jet Propulsion Laboratory, Pasadena, CA 91109, USA
| | - L Paganini
- NASA Headquarters, Washington, DC 20546, USA
| | - J Stansberry
- Space Telescope Science Institute, Baltimore, MD 21218, USA
| | - J Spencer
- Southwest Research Institute, Boulder, CO 80302, USA
| | - S Protopapa
- Southwest Research Institute, Boulder, CO 80302, USA
| | - G Strazzulla
- Osservatorio Astrofisico di Catania, Istituto Nazionale di Astrofisica, 95123 Catania, Italy
| | - G Cruz-Mermy
- Universite Paris-Sarclay, 91190 Gif-sur-Yvette, France
| | - C R Glein
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - R Cartwright
- Carl Sagan Center for Research, Search for Extraterrestrial Intelligence Institute, Mountain View, CA 94043, USA
| | - G Liuzzi
- Università degli Studi della Basilicata, 85100 Potenza, Italy
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7
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Collins GC, Patterson GW, Detelich CE, Prockter LM, Kattenhorn SA, Cooper CM, Rhoden AR, Cutler BB, Oldrid SR, Perkins RP, Rezza CA. Episodic Plate Tectonics on Europa: Evidence for Widespread Patches of Mobile-Lid Behavior in the Antijovian Hemisphere. JOURNAL OF GEOPHYSICAL RESEARCH. PLANETS 2022; 127:e2022JE007492. [PMID: 37035521 PMCID: PMC10078521 DOI: 10.1029/2022je007492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 10/25/2022] [Accepted: 11/01/2022] [Indexed: 06/19/2023]
Abstract
A nearly pole-to-pole survey near 140°E longitude on Europa revealed many areas that exhibit past lateral surface motions, and these areas were examined to determine whether the motions can be described by systems of rigid plates moving across Europa's surface. Three areas showing plate-like behavior were examined in detail to determine the sequence of events that deformed the surface. All three areas were reconstructed to reveal the original pre-plate motion surfaces by performing multi-stage rotations of plates in spherical coordinates. Several motions observed along single plate boundaries were also noted in previous works, but this work links together isolated observations of lateral offsets into integrated systems of moving plates. Not all of the surveyed surface could be described by systems of rigid plates. There is evidence that the plate motions did not all happen at the same time, and that they are not happening today. We conclude that plate tectonic-like behavior on Europa occurs episodically, in limited regions, with less than 100 km of lateral motion accommodated along any particular boundary before plate motions cease. Europa may represent a world perched on the theoretical boundary between stagnant and mobile lid convective behavior, or it may represent an additional example of the wide variations in possible planetary convective regimes. Differences in observed strike-slip sense and plate rotation directions between the northern and southern hemispheres raise the question of whether tidal forces may influence plate motions.
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Affiliation(s)
| | | | - Charlene E. Detelich
- Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
- Now at Cornell UniversityIthacaNYUSA
| | | | | | | | | | | | | | - Reid P. Perkins
- Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
- Now at Western UniversityLondonONCanada
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8
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Wolfenbarger NS, Buffo JJ, Soderlund KM, Blankenship DD. Ice Shell Structure and Composition of Ocean Worlds: Insights from Accreted Ice on Earth. ASTROBIOLOGY 2022; 22:937-961. [PMID: 35787145 DOI: 10.1089/ast.2021.0044] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Accreted ice retains and preserves traces of the ocean from which it formed. In this work, we study two classes of accreted ice found on Earth-frazil ice, which forms through crystallization within a supercooled water column, and congelation ice, which forms through directional freezing at an existing interface-and discuss where each might be found in the ice shells of ocean worlds. We focus our study on terrestrial ice formed in low temperature gradient environments (e.g., beneath ice shelves), consistent with conditions expected at the ice-ocean interfaces of Europa and Enceladus, and we highlight the juxtaposition of compositional trends in relation to ice formed in higher temperature gradient environments (e.g., at the ocean surface). Observations from Antarctic sub-ice-shelf congelation ice and marine ice show that the purity of frazil ice can be nearly two orders of magnitude higher than congelation ice formed in the same low temperature gradient environment (∼0.1% vs. ∼10% of the ocean salinity). In addition, where congelation ice can maintain a planar ice-water interface on a microstructural scale, the efficiency of salt rejection is enhanced (∼1% of the ocean salinity) and lattice soluble impurities such as chloride are preferentially incorporated. We conclude that an ice shell that forms by gradual thickening as its interior cools would be composed of congelation ice, whereas frazil ice will accumulate where the ice shell thins on local (rifts and basal fractures) or regional (latitudinal gradients) scales through the operation of an "ice pump."
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Affiliation(s)
| | - Jacob J Buffo
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | - Krista M Soderlund
- Institute for Geophysics, University of Texas at Austin, Austin, Texas, USA
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9
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Leonard EJ, Howell SM, Mills A, Senske DA, Patthoff DA, Hay HCFC, Pappalardo RT. Finding Order in Chaos: Quantitative Predictors of Chaos Terrain Morphology on Europa. GEOPHYSICAL RESEARCH LETTERS 2022; 49:e2021GL097309. [PMID: 35866056 PMCID: PMC9287068 DOI: 10.1029/2021gl097309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 03/23/2022] [Accepted: 03/28/2022] [Indexed: 06/15/2023]
Abstract
The mechanisms for chaos terrain formation on Europa have long been a source of debate in the scientific community. There exist numerous theoretical and numerical models for chaos formation, but to date there has been a lack of quantifiable observations that can be used to constrain models and permit comparison to the outputs of these chaos models. Here, we use mapping and statistical analysis to develop a quantitative description of chaos terrain and their observed morphologies. For nine chaos features, we map every block, or region of pre-existing terrain within disrupted matrix. We demonstrate that chaos terrains follow a continuous spectrum of morphologies between two endmembers, platy and knobby. We find that any given chaos terrain's morphology can be quantified by means of the linearized exponential slope of its cumulative block area distribution. This quantitative metric provides a new diagnostic parameter in future studies of chaos terrain formation and comparison.
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Affiliation(s)
- E. J. Leonard
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - S. M. Howell
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - A. Mills
- University of AlabamaTuscaloosaALUSA
| | - D. A. Senske
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | | | - H. C. F. C. Hay
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - R. T. Pappalardo
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
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10
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Culberg R, Schroeder DM, Steinbrügge G. Double ridge formation over shallow water sills on Jupiter's moon Europa. Nat Commun 2022; 13:2007. [PMID: 35440535 PMCID: PMC9018861 DOI: 10.1038/s41467-022-29458-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 02/24/2022] [Indexed: 11/09/2022] Open
Abstract
Jupiter's moon Europa is a prime candidate for extraterrestrial habitability in our solar system. The surface landforms of its ice shell express the subsurface structure, dynamics, and exchange governing this potential. Double ridges are the most common surface feature on Europa and occur across every sector of the moon, but their formation is poorly understood, with current hypotheses providing competing and incomplete mechanisms for the development of their distinct morphology. Here we present the discovery and analysis of a double ridge in Northwest Greenland with the same gravity-scaled geometry as those found on Europa. Using surface elevation and radar sounding data, we show that this double ridge was formed by successive refreezing, pressurization, and fracture of a shallow water sill within the ice sheet. If the same process is responsible for Europa's double ridges, our results suggest that shallow liquid water is spatially and temporally ubiquitous across Europa's ice shell.
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Affiliation(s)
- Riley Culberg
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA.
| | - Dustin M Schroeder
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA.,Department of Geophysics, Stanford University, Stanford, CA, USA
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11
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Bland MT, Elder CM. Silicate Volcanism on Europa's Seafloor and Implications for Habitability. GEOPHYSICAL RESEARCH LETTERS 2022; 49:e2021GL096939. [PMID: 35866068 PMCID: PMC9286870 DOI: 10.1029/2021gl096939] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 01/27/2022] [Accepted: 01/28/2022] [Indexed: 06/15/2023]
Abstract
Habitable ocean environments on Europa require an influx of reactants to maintain chemical disequilibrium. One possible source of reactants is seafloor volcanism. Modeling has shown that dissipation of tidal energy in Europa's asthenosphere can generate melt, but melt formation cannot be equated with volcanism. Melt must also be transported through Europa's cold lithosphere to erupt at the seafloor. Here, we use two models of dike propagation to show that dikes can only traverse the lithosphere if either the fracture toughness of the lithosphere or the flux into the dike is large (>500 MPa m1/2 or ∼1 m2 s-1, respectively). We conclude that cyclic volcanic episodes might provide reactants to Europa's ocean if magma accumulates at the base of the lithosphere for several thousand years. However, if dikes form too frequently, or are too numerous, the magma flux into each will be insufficient, and volcanism cannot support a habitable ocean environment.
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Affiliation(s)
- M. T. Bland
- Astrogeology Science CenterU. S. Geological SurveyFlagstaffAZUSA
| | - C. M. Elder
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
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12
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Thompson SP, Kennedy H, Butler BM, Day SJ, Safi E, Evans A. Laboratory exploration of mineral precipitates from Europa's subsurface ocean. J Appl Crystallogr 2021; 54:1455-1479. [PMID: 34667451 PMCID: PMC8493616 DOI: 10.1107/s1600576721008554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 08/17/2021] [Indexed: 11/10/2022] Open
Abstract
The precipitation of hydrated phases from a chondrite-like Na-Mg-Ca-SO4-Cl solution is studied using in situ synchrotron X-ray powder diffraction, under rapid- (360 K h-1, T = 250-80 K, t = 3 h) and ultra-slow-freezing (0.3 K day-1, T = 273-245 K, t = 242 days) conditions. The precipitation sequence under slow cooling initially follows the predictions of equilibrium thermodynamics models. However, after ∼50 days at 245 K, the formation of the highly hydrated sulfate phase Na2Mg(SO4)2·16H2O, a relatively recent discovery in the Na2Mg(SO4)2-H2O system, was observed. Rapid freezing, on the other hand, produced an assemblage of multiple phases which formed within a very short timescale (≤4 min, ΔT = 2 K) and, although remaining present throughout, varied in their relative proportions with decreasing temperature. Mirabilite and meridianiite were the major phases, with pentahydrite, epsomite, hydrohalite, gypsum, blödite, konyaite and loweite also observed. Na2Mg(SO4)2·16H2O was again found to be present and increased in proportion relative to other phases as the temperature decreased. The results are discussed in relation to possible implications for life on Europa and application to other icy ocean worlds.
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Affiliation(s)
- Stephen P. Thompson
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Hilary Kennedy
- School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey LL59 5AB, United Kingdom
| | - Benjamin M. Butler
- Environmental and Biochemical Sciences, The James Hutton Institute, Craigiebuckler, Aberdeen AB15 8QH, United Kingdom
| | - Sarah J. Day
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Emmal Safi
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
- Astrophysics Group, Lennard-Jones Laboratories, Keele University, Keele, Staffordshire ST5 5BG, United Kingdom
| | - Aneurin Evans
- Astrophysics Group, Lennard-Jones Laboratories, Keele University, Keele, Staffordshire ST5 5BG, United Kingdom
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13
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Seaton KM, Cable ML, Stockton AM. Analytical Chemistry in Astrobiology. Anal Chem 2021; 93:5981-5997. [PMID: 33835785 DOI: 10.1021/acs.analchem.0c04271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This Feature introduces and discusses the findings of key analytical techniques used to study planetary bodies in our solar system in the search for life beyond Earth, future missions planned for high-priority astrobiology targets in our solar system, and the challenges we face in performing these investigations.
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Affiliation(s)
- Kenneth Marshall Seaton
- School of Chemistry & Biochemistry, Georgia Institute of Technology, North Avenue NW, Atlanta, Georgia 30332, United States
| | - Morgan Leigh Cable
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
| | - Amanda Michelle Stockton
- School of Chemistry & Biochemistry, Georgia Institute of Technology, North Avenue NW, Atlanta, Georgia 30332, United States
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14
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Castillo-Rogez JC, Neveu M, Scully JEC, House CH, Quick LC, Bouquet A, Miller K, Bland M, De Sanctis MC, Ermakov A, Hendrix AR, Prettyman TH, Raymond CA, Russell CT, Sherwood BE, Young E. Ceres: Astrobiological Target and Possible Ocean World. ASTROBIOLOGY 2020; 20:269-291. [PMID: 31904989 DOI: 10.1089/ast.2018.1999] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Ceres, the most water-rich body in the inner solar system after Earth, has recently been recognized to have astrobiological importance. Chemical and physical measurements obtained by the Dawn mission enabled the quantification of key parameters, which helped to constrain the habitability of the inner solar system's only dwarf planet. The surface chemistry and internal structure of Ceres testify to a protracted history of reactions between liquid water, rock, and likely organic compounds. We review the clues on chemical composition, temperature, and prospects for long-term occurrence of liquid and chemical gradients. Comparisons with giant planet satellites indicate similarities both from a chemical evolution standpoint and in the physical mechanisms driving Ceres' internal evolution.
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Affiliation(s)
| | - Marc Neveu
- Sciences and Exploration Directorate, NASA Goddard Space Flight Center, Greenbelt, Maryland
- University of Maryland College Park, Greenbelt, Maryland
| | - Jennifer E C Scully
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
| | - Christopher H House
- Department of Geosciences,Penn State Astrobiology Research Center, The Pennsylvania State University, University Park, Pennsylvania
| | - Lynnae C Quick
- Sciences and Exploration Directorate, NASA Goddard Space Flight Center, Greenbelt, Maryland
| | - Alexis Bouquet
- LAM (Laboratoire d'Astrophysique de Marseille), Aix Marseille Université, CNRS, UMR 7326, Marseille, France
| | - Kelly Miller
- Southwest Research Institute, San Antonio, Texas
| | | | | | - Anton Ermakov
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
| | | | | | - Carol A Raymond
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
| | - Christopher T Russell
- Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, California
| | | | - Edward Young
- Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, California
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15
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Cosciotti B, Balbi A, Ceccarelli A, Fagliarone C, Mattei E, Lauro SE, Di Paolo F, Pettinelli E, Billi D. Survivability of Anhydrobiotic Cyanobacteria in Salty Ice: Implications for the Habitability of Icy Worlds. Life (Basel) 2019; 9:life9040086. [PMID: 31766612 PMCID: PMC6958388 DOI: 10.3390/life9040086] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Revised: 11/14/2019] [Accepted: 11/19/2019] [Indexed: 11/16/2022] Open
Abstract
Two anhydrobiotic strains of the cyanobacterium Chroococcidiopsis, namely CCMEE 029 and CCMEE 171, isolated from the Negev Desert in Israel and from the Dry Valleys in Antarctica, were exposed to salty-ice simulations. The aim of the experiment was to investigate the cyanobacterial capability to survive under sub-freezing temperatures in samples simulating the environment of icy worlds. The two strains were mixed with liquid solutions having sub-eutectic concentration of Na2SO4, MgSO4 and NaCl, then frozen down to different final temperatures (258 K, 233 K and 203 K) in various experimental runs. Both strains survived the exposure to 258 K in NaCl solution, probably as they migrated in the liquid veins between ice grain boundaries. However, they also survived at 258 K in Na2SO4 and MgSO4-salty-ice samples-that is, a temperature well below the eutectic temperature of the solutions, where liquid veins should not exist anymore. Moreover, both strains survived the exposure at 233 K in each salty-ice sample, with CCMEE 171 showing an enhanced survivability, whereas there were no survivors at 203 K. The survival limit at low temperature was further extended when both strains were exposed to 193 K as air-dried cells. The results suggest that vitrification might be a strategy for microbial life forms to survive in potentially habitable icy moons, for example in Europa's icy crust. By entering a dried, frozen state, they could be transported from niches, which became non-habitable to new habitable ones, and possibly return to metabolic activity.
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Affiliation(s)
- Barbara Cosciotti
- Department of Mathematics and Physics, University of Rome Tre, 00154 Rome, Italy; (B.C.); (A.C.); (E.M.); (S.E.L.); (F.D.P.); (E.P.)
| | - Amedeo Balbi
- Department of Physics, University of Rome Tor Vergata, 00133 Rome, Italy;
| | - Alessandra Ceccarelli
- Department of Mathematics and Physics, University of Rome Tre, 00154 Rome, Italy; (B.C.); (A.C.); (E.M.); (S.E.L.); (F.D.P.); (E.P.)
| | - Claudia Fagliarone
- Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy;
| | - Elisabetta Mattei
- Department of Mathematics and Physics, University of Rome Tre, 00154 Rome, Italy; (B.C.); (A.C.); (E.M.); (S.E.L.); (F.D.P.); (E.P.)
| | - Sebastian Emanuel Lauro
- Department of Mathematics and Physics, University of Rome Tre, 00154 Rome, Italy; (B.C.); (A.C.); (E.M.); (S.E.L.); (F.D.P.); (E.P.)
| | - Federico Di Paolo
- Department of Mathematics and Physics, University of Rome Tre, 00154 Rome, Italy; (B.C.); (A.C.); (E.M.); (S.E.L.); (F.D.P.); (E.P.)
| | - Elena Pettinelli
- Department of Mathematics and Physics, University of Rome Tre, 00154 Rome, Italy; (B.C.); (A.C.); (E.M.); (S.E.L.); (F.D.P.); (E.P.)
| | - Daniela Billi
- Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy;
- Correspondence:
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16
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Ashkenazy Y. The surface temperature of Europa. Heliyon 2019; 5:e01908. [PMID: 31294099 PMCID: PMC6595243 DOI: 10.1016/j.heliyon.2019.e01908] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 03/10/2019] [Accepted: 06/03/2019] [Indexed: 11/01/2022] Open
Abstract
Previous estimates of the annual mean surface temperature of Jupiter's moon, Europa, neglected the effect of the eccentricity of Jupiter's orbit around the Sun, the effect of the emissivity and heat capacity of Europa's ice, the effect of the eclipse of Europa (i.e., the relative time that Europa is within the shadow of Jupiter), the effect of Jupiter's radiation, and the effect of Europa's internal heating. Other studies concentrated on the diurnal cycle but neglected some of the above factors. In addition, to our knowledge, the seasonal cycle of the surface temperature of Europa was not estimated. Here we systematically estimate the diurnal, seasonal and annual mean surface temperature of Europa, when Europa's obliquity, emissivity, heat capacity, and eclipse, as well as Jupiter's radiation, internal heating, and eccentricity, are all taken into account. For a typical internal heating rate of 0.05 W m - 2 , the equator, pole, and the global and mean annual mean surface temperatures are 96 K, 46 K, and 90 K, respectively. We found that the temperature at the high latitudes is significantly affected by the internal heating, especially during the winter solstice, suggesting that measurements of high latitude surface temperatures can be used to constrain the internal heating. We also estimate the incoming solar radiation to Enceladus, the moon of Saturn.
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Affiliation(s)
- Yosef Ashkenazy
- Department of Solar Energy and Environmental Physics, BIDR, Ben-Gurion University, Midreshet Ben-Gurion, Israel
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17
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Russell MJ, Murray AE, Hand KP. The Possible Emergence of Life and Differentiation of a Shallow Biosphere on Irradiated Icy Worlds: The Example of Europa. ASTROBIOLOGY 2017; 17:1265-1273. [PMID: 29016193 PMCID: PMC5729856 DOI: 10.1089/ast.2016.1600] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 04/28/2017] [Indexed: 05/17/2023]
Abstract
Irradiated ice-covered ocean worlds with rocky mafic mantles may provide the conditions needed to drive the emergence and maintenance of life. Alkaline hydrothermal springs-relieving the geophysical, thermal, and chemical disequilibria between oceans and tidally stressed crusts-could generate inorganic barriers to the otherwise uncontrolled and kinetically disfavored oxidation of hydrothermal hydrogen and methane. Ionic gradients imposed across these inorganic barriers, comprising iron oxyhydroxides and sulfides, could drive the hydrogenation of carbon dioxide and the oxidation of methane through thermodynamically favorable metabolic pathways leading to early life-forms. In such chemostatic environments, fuels may eventually outweigh oxidants. Ice-covered oceans are primarily heated from below, creating convection that could transport putative microbial cells and cellular cooperatives upward to congregate beneath an ice shell, potentially giving rise to a highly focused shallow biosphere. It is here where electron acceptors, ultimately derived from the irradiated surface, could be delivered to such life-forms through exchange with the icy surface. Such zones would act as "electron disposal units" for the biosphere, and occupants might be transferred toward the surface by buoyant diapirs and even entrained into plumes. Key Words: Biofilms-Europa-Extraterrestrial life-Hydrothermal systems. Astrobiology 17, 1265-1273.
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Affiliation(s)
- Michael J. Russell
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
| | - Alison E. Murray
- Division of Earth and Ecosystem Sciences, Desert Research Institute, Reno, Nevada
| | - Kevin P. Hand
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
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Loeffler MJ, Hudson RL. Descent without Modification? The Thermal Chemistry of H2O2 on Europa and Other Icy Worlds. ASTROBIOLOGY 2015; 15:453-461. [PMID: 26060983 DOI: 10.1089/ast.2014.1195] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The strong oxidant H2O2 is known to exist in solid form on Europa and is suspected to exist on several other Solar System worlds at temperatures below 200 K. However, little is known of the thermal chemistry that H2O2 might induce under these conditions. Here, we report new laboratory results on the reactivity of solid H2O2 with eight different compounds in H2O-rich ices. Using infrared spectroscopy, we monitored compositional changes in ice mixtures during warming. The compounds CH4 (methane), C3H4 (propyne), CH3OH (methanol), and CH3CN (acetonitrile) were unaltered by the presence of H2O2 in ices, showing that exposure to either solid H2O2 or frozen H2O+H2O2 at cryogenic temperatures will not oxidize these organics, much less convert them to CO2. This contrasts strongly with the much greater reactivity of organics with H2O2 at higher temperatures, and particularly in the liquid and gas phases. Of the four inorganic compounds studied, CO, H2S, NH3, and SO2, only the last two reacted in ices containing H2O2, NH3 making NH4+ and SO2 making SO(4)2- by H+ and e- transfer, respectively. An important astrobiological conclusion is that formation of surface H2O2 on Europa and that molecule's downward movement with H2O-ice do not necessarily mean that all organics encountered in icy subsurface regions will be destroyed by H2O2 oxidation.
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Affiliation(s)
- Mark J Loeffler
- Astrochemistry Laboratory, NASA Goddard Space Flight Center , Greenbelt, Maryland
| | - Reggie L Hudson
- Astrochemistry Laboratory, NASA Goddard Space Flight Center , Greenbelt, Maryland
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Fujii Y, Kimura J, Dohm J, Ohtake M. Geology and photometric variation of solar system bodies with minor atmospheres: implications for solid exoplanets. ASTROBIOLOGY 2014; 14:753-68. [PMID: 25238324 PMCID: PMC4172389 DOI: 10.1089/ast.2014.1165] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 07/19/2014] [Indexed: 05/21/2023]
Abstract
A reasonable basis for future astronomical investigations of exoplanets lies in our best knowledge of the planets and satellites in the Solar System. Solar System bodies exhibit a wide variety of surface environments, even including potential habitable conditions beyond Earth, and it is essential to know how they can be characterized from outside the Solar System. In this study, we provide an overview of geological features of major Solar System solid bodies with minor atmospheres (i.e., the terrestrial Moon, Mercury, the Galilean moons, and Mars) that affect surface albedo at local to global scale, and we survey how they influence point-source photometry in the UV/visible/near IR (i.e., the reflection-dominant range). We simulate them based on recent mapping products and also compile observed light curves where available. We show a 5-50% peak-to-trough variation amplitude in one spin rotation associated with various geological processes including heterogeneous surface compositions due to igneous activities, interaction with surrounding energetic particles, and distribution of grained materials. Some indications of these processes are provided by the amplitude and wavelength dependence of variation in combinations of the time-averaged spectra. We also estimate the photometric precision needed to detect their spin rotation rates through periodogram analysis. Our survey illustrates realistic possibilities for inferring the detailed properties of solid exoplanets with future direct imaging observations. Key Words: Planetary environments-Planetary geology-Solar System-Extrasolar terrestrial planets.
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Affiliation(s)
- Yuka Fujii
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan
| | - Jun Kimura
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan
| | - James Dohm
- The University Museum, The University of Tokyo, Tokyo, Japan
| | - Makiko Ohtake
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Kanagawa, Japan
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Pappalardo RT, Vance S, Bagenal F, Bills BG, Blaney DL, Blankenship DD, Brinckerhoff WB, Connerney JEP, Hand KP, Hoehler TM, Leisner JS, Kurth WS, McGrath MA, Mellon MT, Moore JM, Patterson GW, Prockter LM, Senske DA, Schmidt BE, Shock EL, Smith DE, Soderlund KM. Science potential from a Europa lander. ASTROBIOLOGY 2013; 13:740-773. [PMID: 23924246 DOI: 10.1089/ast.2013.1003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The prospect of a future soft landing on the surface of Europa is enticing, as it would create science opportunities that could not be achieved through flyby or orbital remote sensing, with direct relevance to Europa's potential habitability. Here, we summarize the science of a Europa lander concept, as developed by our NASA-commissioned Science Definition Team. The science concept concentrates on observations that can best be achieved by in situ examination of Europa from its surface. We discuss the suggested science objectives and investigations for a Europa lander mission, along with a model planning payload of instruments that could address these objectives. The highest priority is active sampling of Europa's non-ice material from at least two different depths (0.5-2 cm and 5-10 cm) to understand its detailed composition and chemistry and the specific nature of salts, any organic materials, and other contaminants. A secondary focus is geophysical prospecting of Europa, through seismology and magnetometry, to probe the satellite's ice shell and ocean. Finally, the surface geology can be characterized in situ at a human scale. A Europa lander could take advantage of the complex radiation environment of the satellite, landing where modeling suggests that radiation is about an order of magnitude less intense than in other regions. However, to choose a landing site that is safe and would yield the maximum science return, thorough reconnaissance of Europa would be required prior to selecting a scientifically optimized landing site.
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Affiliation(s)
- R T Pappalardo
- Planetary Sciences Section, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA.
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Dachwald B, Ulamec S, Biele J. Clean In Situ Subsurface Exploration of Icy Environments in the Solar System. ACTA ACUST UNITED AC 2013. [DOI: 10.1007/978-94-007-6546-7_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
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Active formation of 'chaos terrain' over shallow subsurface water on Europa. Nature 2011; 479:502-5. [PMID: 22089135 DOI: 10.1038/nature10608] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2011] [Accepted: 10/04/2011] [Indexed: 11/08/2022]
Abstract
Europa, the innermost icy satellite of Jupiter, has a tortured young surface and sustains a liquid water ocean below an ice shell of highly debated thickness. Quasi-circular areas of ice disruption called chaos terrains are unique to Europa, and both their formation and the ice-shell thickness depend on Europa's thermal state. No model so far has been able to explain why features such as Conamara Chaos stand above surrounding terrain and contain matrix domes. Melt-through of a thin (few-kilometre) shell is thermodynamically improbable and cannot raise the ice. The buoyancy of material rising as either plumes of warm, pure ice called diapirs or convective cells in a thick (>10 kilometres) shell is insufficient to produce the observed chaos heights, and no single plume can create matrix domes. Here we report an analysis of archival data from Europa, guided by processes observed within Earth's subglacial volcanoes and ice shelves. The data suggest that chaos terrains form above liquid water lenses perched within the ice shell as shallow as 3 kilometres. Our results suggest that ice-water interactions and freeze-out give rise to the diverse morphologies and topography of chaos terrains. The sunken topography of Thera Macula indicates that Europa is actively resurfacing over a lens comparable in volume to the Great Lakes in North America.
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Greenberg R. Exploration and protection of Europa's biosphere: implications of permeable ice. ASTROBIOLOGY 2011; 11:183-191. [PMID: 21417946 DOI: 10.1089/ast.2011.0608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Europa has become a high-priority objective for exploration because it may harbor life. Strategic planning for its exploration has been predicated on an extreme model in which the expected oceanic biosphere lies under a thick ice crust, buried too deep to be reached in the foreseeable future, which would beg the question of whether other active satellites might be more realistic objectives. However, Europa's ice may in fact be permeable, with very different implications for the possibilities for life and for mission planning. A biosphere may extend up to near the surface, making life far more readily accessible to exploration while at the same time making it vulnerable to contamination. The chances of finding life on Europa are substantially improved while the need for planetary protection becomes essential. The new National Research Council planetary protection study will need to go beyond its current mandate if meaningful standards are to be put in place.
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Affiliation(s)
- Richard Greenberg
- Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona 85719, USA.
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Pauer M, Musiol S, Breuer D. Gravity signals on Europa from silicate shell density variations. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2010je003595] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
AbstractGalileo spacecraft data suggest that a global ocean exists beneath the frozen ice surface Jupiter's moon Europa. Since the early 1970s, planetary scientists have used theoretical and observational arguments to deliberate the existence of an ocean within Europa and other large icy satellites. Galileo magnetometry data indicates an induced magnetic field at Europa, implying a salt water ocean. A paucity of large craters argues for a surface on average only ~40-90 Myr old. Two multi-ring structures suggest that impacts punched through an ice shell ~20 km thick. Europa's ocean and surface are inherently linked through tidal deformation of the floating ice shell, and tidal flexing and nonsynchronous rotation generate stresses that fracture and deform the surface to create ridges and bands. Dark spots, domes, and chaos terrain are probably related to tidally driven ice convection along with partial melting within the ice shell. Europa's geological activity and probable mantle contact permit the chemical ingredients necessary for life to be present within the satellite's ocean. Astonishing geology and high astrobiological potential make Europa a top priority for future spacecraft exploration, with a primary goal of assessing its habitability.
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Hand KP, Carlson RW, Chyba CF. Energy, chemical disequilibrium, and geological constraints on Europa. ASTROBIOLOGY 2007; 7:1006-1022. [PMID: 18163875 DOI: 10.1089/ast.2007.0156] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Europa is a prime target for astrobiology. The presence of a global subsurface liquid water ocean and a composition likely to contain a suite of biogenic elements make it a compelling world in the search for a second origin of life. Critical to these factors, however, may be the availability of energy for biological processes on Europa. We have examined the production and availability of oxidants and carbon-containing reductants on Europa to better understand the habitability of the subsurface ocean. Data from the Galileo Near-Infrared Mapping Spectrometer were used to constrain the surface abundance of CO(2) to 0.036% by number relative to water. Laboratory results indicate that radiolytically processed CO(2)-rich ices yield CO and H(2)CO(3); the reductants H(2)CO, CH(3)OH, and CH(4) are at most minor species. We analyzed chemical sources and sinks and concluded that the radiolytically processed surface of Europa could serve to maintain an oxidized ocean even if the surface oxidants (O(2), H(2)O(2), CO(2), SO(2), and SO(4) (2)) are delivered only once every approximately 0.5 Gyr. If delivery periods are comparable to the observed surface age (30-70 Myr), then Europa's ocean could reach O(2) concentrations comparable to those found in terrestrial surface waters, even if approximately 10(9) moles yr(1) of hydrothermally delivered reductants consume most of the oxidant flux. Such an ocean would be energetically hospitable for terrestrial marine macrofauna. The availability of reductants could be the limiting factor for biologically useful chemical energy on Europa.
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Affiliation(s)
- Kevin P Hand
- Department of Geological & Environmental Sciences, Stanford University, Stanford, California, USA.
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Ruiz J, Montoya L, López V, Amils R. Thermal diapirism and the habitability of the icy shell of Europa. ORIGINS LIFE EVOL B 2007; 37:287-95. [PMID: 17361321 DOI: 10.1007/s11084-007-9068-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2007] [Accepted: 02/19/2007] [Indexed: 10/23/2022]
Abstract
Europa's chaos and lenticulae features may have originated by thermal diapirs related to convective plumes. Warm ice plumes could be habitable, since their temperature is close to the ice melting temperature. Moreover, thermal plumes intruding into the lower stagnant lid warm several kilometers of country ice above 230 K for periods of 10(5) years, and hundreds of meters above 240 K for periods of 10(4) years. Diapir coalescence generating chaos areas should provide a large zone with temperature above approximately 240 K for thousands of years. A temperature above approximately 230 K is potentially interesting for astrobiology, since it corresponds to the lowest temperature at which microbial metabolic activity in Antarctic ice has been reported. So, the warming by thermal plumes could cause an aureole of biological activation/reactivation in the country ice. Adaptation of life to either high salinity or low temperature is similar: it requires the synthesis of compatible solutes, like trehalose or glycerol, which are efficient cryoprotectants. We therefore propose that the future astrobiological exploration of Europa should include the search for compatible solutes in chaos and lenticulae features.
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Affiliation(s)
- Javier Ruiz
- Instituto de Astrofísica de Andalucía, CSIC, Camino Bajo de Huétor 50, 18008 Granada, Spain.
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Nimmo F, Spencer JR, Pappalardo RT, Mullen ME. Shear heating as the origin of the plumes and heat flux on Enceladus. Nature 2007; 447:289-91. [PMID: 17507976 DOI: 10.1038/nature05783] [Citation(s) in RCA: 196] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2006] [Accepted: 03/22/2007] [Indexed: 11/10/2022]
Abstract
Enceladus, a small icy satellite of Saturn, has active plumes jetting from localized fractures ('tiger stripes') within an area of high heat flux near the south pole. The plume characteristics and local high heat flux have been ascribed either to the presence of liquid water within a few tens of metres of the surface, or the decomposition of clathrates. Neither model addresses how delivery of internal heat to the near-surface is sustained. Here we show that the most likely explanation for the heat and vapour production is shear heating by tidally driven lateral (strike-slip) fault motion with displacement of approximately 0.5 m over a tidal period. Vapour produced by this heating may escape as plumes through cracks reopened by the tidal stresses. The ice shell thickness needed to produce the observed heat flux is at least 5 km. The tidal displacements required imply a Love number of h2 > 0.01, suggesting that the ice shell is decoupled from the silicate interior by a subsurface ocean. We predict that the tiger-stripe regions with highest relative temperatures will be the lower-latitude branch of Damascus, Cairo around 60 degrees W longitude and Alexandria around 150 degrees W longitude.
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Affiliation(s)
- F Nimmo
- Department of Earth and Planetary Sciences, University of California Santa Cruz, 1156 High Street, Santa Cruz, California 95064, USA.
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Hand KP, Chyba CF, Carlson RW, Cooper JF. Clathrate hydrates of oxidants in the ice shell of Europa. ASTROBIOLOGY 2006; 6:463-82. [PMID: 16805702 DOI: 10.1089/ast.2006.6.463] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Europa's icy surface is radiolytically modified by high-energy electrons and ions, and photolytically modified by solar ultraviolet photons. Observations from the Galileo Near Infrared Mapping Spectrometer, ground-based telescopes, the International Ultraviolet Explorer, and the Hubble Space Telescope, along with laboratory experiment results, indicate that the production of oxidants, such as H2O2, O2, CO2, and SO2, is a consequence of the surface radiolytic chemistry. Once created, some of the products may be entrained deeper into the ice shell through impact gardening or other resurfacing processes. The temperature and pressure environments of regions within the europan hydrosphere are expected to permit the formation of mixed clathrate compounds. The formation of carbon dioxide and sulfur dioxide clathrates has been examined in some detail. Here we add to this analysis by considering oxidants produced radiolytically on the surface of Europa. Our results indicate that the bulk ice shell could have a approximately 1.7-7.6% by number contamination of oxidants resulting from radiolysis at the surface. Oxidant-hosting clathrates would consequently make up approximately 12-53% of the ice shell by number relative to ice, if oxidants were entrained throughout. We examine, in brief, the consequences of such contamination on bulk ice shell thickness and find that clathrate formation could lead to substantially thinner ice shells on Europa than otherwise expected. Finally, we propose that double occupancy of clathrate cages by O2 molecules could serve as an explanation for the observation of condensed-phase O2 on Europa. Clathrate-sealed, gas-filled bubbles in the near surface ice could also provide an effective trapping mechanism, though they cannot explain the 5771 A (O2)2 absorption.
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Affiliation(s)
- Kevin P Hand
- Department of Geological & Environmental Sciences, Stanford University, Stanford, California 94305, USA.
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Tung HC, Price PB, Bramall NE, Vrdoljak G. Microorganisms metabolizing on clay grains in 3-km-deep Greenland basal ice. ASTROBIOLOGY 2006; 6:69-86. [PMID: 16551227 DOI: 10.1089/ast.2006.6.69] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
We have discovered > 10(8) microbial cells/cm3 attached to clay grains in the bottom 13 m of the GISP2 (Greenland Ice Sheet Project) ice core. Their concentration correlates with huge excesses of CO2 and CH4. We show that Fe-reducing bacteria produce most of the excess CO2 and methanogenic archaea produce the excess CH4. The number of attached cells per clay grain is proportional to grain perimeter rather than to area, which implies that nutrients are accessed at grain edges. We conclude that Fe-reducing microbes immobilized on clay surfaces metabolize via "shuttle" molecules that transport electrons to grain edges, where they reduce Fe(III) ions at edges to Fe(II) while organic acid ions are oxidized to CO2. Driven by the concentration gradient, electrons on Fe(II) ions at grain edges "hop" to Fe(III) ions inward in the same edges and oxidize them. The original Fe(III) ions can then attach new electrons from shuttle molecules at the edges. Our mechanism explains how Fe-reducers can reduce essentially all Fe(III) in clay minerals. We estimate that the Fe(III) in clay grains in the GISP2 silty ice can sustain Fe-reducing bacteria at the ambient temperature of -9 degrees C for approximately 10(6) years. F420 autofluorescence imaging shows that > 2.4% of the cells are methanogens, which account for the excess methane.
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Affiliation(s)
- H C Tung
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, California 94720, USA
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Durham WB, Stern LA, Kubo T, Kirby SH. Flow strength of highly hydrated Mg- and Na-sulfate hydrate salts, pure and in mixtures with water ice, with application to Europa. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2005je002475] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Barr AC, Pappalardo RT. Onset of convection in the icy Galilean satellites: Influence of rheology. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2004je002371] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Goodman JC. Hydrothermal plume dynamics on Europa: Implications for chaos formation. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2003je002073] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Manga M. Formation of bands and ridges on Europa by cyclic deformation: Insights from analogue wax experiments. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2004je002249] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Nimmo F. Stresses generated in cooling viscoelastic ice shells: Application to Europa. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2004je002347] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Showman AP. Numerical simulations of convection in Europa's ice shell: Implications for surface features. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2003je002103] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Fagents SA. Considerations for effusive cryovolcanism on Europa: The post-Galileo perspective. ACTA ACUST UNITED AC 2003. [DOI: 10.1029/2003je002128] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Sarah A. Fagents
- Hawaii Institute of Geophysics and Planetology, School of Ocean and Earth Sciences and Technology; University of Hawaii at Manoa; Honolulu Hawaii USA
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41
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Ice-volcanism due to tidal stress on Europa. CHINESE SCIENCE BULLETIN-CHINESE 2003. [DOI: 10.1007/bf03184185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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42
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Tobie G. Tidally heated convection: Constraints on Europa's ice shell thickness. ACTA ACUST UNITED AC 2003. [DOI: 10.1029/2003je002099] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
Life as we know it on Earth depends on liquid water, a suite of 'biogenic' elements (most famously carbon) and a useful source of free energy. Here we review Europa's suitability for life from the perspective of these three requirements. It is likely, though not yet certain, that Europa harbors a subsurface ocean of liquid water whose volume is about twice that of Earth's oceans. Little is known about Europa's inventory of carbon, nitrogen, and other biogenic elements, but lower bounds on these can be placed by considering the role of commentary delivery over Europa's history. Sources of free energy are challenging for a world covered with an ice layer kilometers thick, but it is possible that hydrothermal activity and/or organics and oxidants provided by the action of radiation chemistry at Europa's surface and subsequent mixing into Europa's ocean could provide the electron donors and acceptors needed to power a Europan ecosystem. It is not premature to draw lessons from the search for life on Mars with the Viking spacecraft for planning exobiological missions to Europa.
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Affiliation(s)
- Christopher F Chyba
- Center for the Study of Life in the Universe, SETI Institute, Mountain View, CA, USA
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46
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Prockter LM. Morphology of Europan bands at high resolution: A mid-ocean ridge-type rift mechanism. ACTA ACUST UNITED AC 2002. [DOI: 10.1029/2000je001458] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Khurana KK, Kivelson MG, Russell CT. Searching for liquid water in Europa by using surface observatories. ASTROBIOLOGY 2002; 2:93-103. [PMID: 12449858 DOI: 10.1089/153110702753621376] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Liquid water, as far as we know, is an indispensable ingredient of life. Therefore, locating reservoirs of liquid water in extraterrestrial bodies is a necessary prerequisite to searching for life. Recent geological and geophysical observations from the Galileo spacecraft, though not unambiguous, hint at the possibility of a subsurface ocean in the Jovian moon Europa. After summarizing present evidence for liquid water in Europa, we show that electromagnetic and seismic observations made from as few as two surface observatories comprising a magnetometer and a seismometer offer the best hope of unambiguous characterization of the three-dimensional structure of the ocean and the deeper interior of this icy moon. The observatories would also help us infer the composition of the icy crust and the ocean water.
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Affiliation(s)
- Krishan K Khurana
- Institute of Geophysics and Planetary Physics, University of California at Los Angeles, Los Angeles, CA, USA.
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La Spisa S, Waldheim M, Lintemoot J, Thomas T, Naff J, Robinson M. Infrared and vapor flux studies of vapor-deposited amorphous and crystalline water ice films between 90 and 145 K. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2000je001305] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Abstract
Several impact craters on Jupiter's satellite Europa exhibit central peaks. On the terrestrial planets, central peaks consist of fractured but competent rock uplifted during cratering. Therefore, the observation of central peaks on Europa indicates that an ice layer must be sufficiently thick that the impact events did not completely penetrate it. We conducted numerical simulations of vapor and melt production during cratering of water ice layers overlying liquid water to estimate the thickness of Europa's icy crust. Because impacts disrupt material well beyond the zone of partial melting, our simulations put a lower limit on ice thickness at the locations and times of impact. We conclude that the ice must be more than 3 to 4 kilometers thick.
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Affiliation(s)
- E P Turtle
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA.
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