DOCSLIB.ORG

An Astrobiology Strategy for the Search for Life in the Universe

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
An Astrobiology Strategy for the Search for Life in the Universe Prepublication Copy – Subject to Further Editorial Correction An Astrobiology Strategy for the Search for Life in the Universe ADVANCE COPY NOT FOR PUBLIC RELEASE BEFORE October 10, 2018 at 11:00 a.m. ___________________________________________________________________________________ PLEASE CITE AS A REPORT OF THE NATIONAL ACADEMIES OF SCIENCES, ENGINEERING, AND MEDICINE Committee on the Astrobiology Science Strategy for the Search for Life in the Universe Space Studies Board Division on Engineering and Physical Sciences A Consensus Study Report of PREPUBLICATION COPY – SUBJECT TO FURTHER EDITORIAL CORRECTION THE NATIONAL ACADEMIES PRESS 500 Fifth Street, NW Washington, DC 20001 This study is based on work supported by the Contract NNH17CB02B with the National Aeronautics and Space Administration. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of any organization or agency that provided support for the project. International Standard Book Number-13: 978-0-309-XXXXX-X International Standard Book Number-10: 0-309-XXXXX-X Digital Object Identifier: https://doi.org/10.17226/25252 Copies of this report are available free of charge from: Space Studies Board National Academies of Sciences, Engineering, and Medicine 500 Fifth Street, NW Washington, DC 20001 Additional copies of this report are available from the National Academies Press, 500 Fifth Street, NW, Keck 360, Washington, DC 20001; (800) 624-6242 or (202) 334-3313; http://www.nap.edu. Copyright 2018 by the National Academy of Sciences. All rights reserved. Printed in the United States of America Suggested Citation: National Academies of Sciences, Engineering, and Medicine. 2018. An Astrobiology Science Strategy for the Search for Life in the Universe. The National Academies Press, Washington, D.C. https://doi.org/10.17226/25252. PREPUBLICATION COPY – SUBJECT TO FURTHER EDITORIAL CORRECTION The National Academy of Sciences was established in 1863 by an Act of Congress, signed by President Lincoln, as a private, nongovernmental institution to advise the nation on issues related to science and technology. Members are elected by their peers for outstanding contributions to research. Dr. Marcia McNutt is president. The National Academy of Engineering was established in 1964 under the charter of the National Academy of Sciences to bring the practices of engineering to advising the nation. Members are elected by their peers for extraordinary contributions to engineering. Dr. C. D. Mote, Jr., is president. The National Academy of Medicine (formerly the Institute of Medicine) was established in 1970 under the charter of the National Academy of Sciences to advise the nation on medical and health issues. Members are elected by their peers for distinguished contributions to medicine and health. Dr. Victor J. Dzau is president. The three Academies work together as the National Academies of Sciences, Engineering, and Medicine to provide independent, objective analysis and advice to the nation and conduct other activities to solve complex problems and inform public policy decisions. The National Academies also encourage education and research, recognize outstanding contributions to knowledge, and increase public understanding in matters of science, engineering, and medicine. Learn more about the National Academies of Sciences, Engineering, and Medicine at www.national-academies.org. PREPUBLICATION COPY – SUBJECT TO FURTHER EDITORIAL CORRECTION Consensus Study Reports published by the National Academies of Sciences, Engineering, and Medicine document the evidence-based consensus on the study’s statement of task by an authoring committee of experts. Reports typically include findings, conclusions, and recommendations based on information gathered by the committee and the committee’s deliberations. Each report has been subjected to a rigorous and independent peer-review process and it represents the position of the National Academies on the statement of task. Proceedings published by the National Academies of Sciences, Engineering, and Medicine chronicle the presentations and discussions at a workshop, symposium, or other event convened by the National Academies. The statements and opinions contained in proceedings are those of the participants and are not endorsed by other participants, the planning committee, or the National Academies. For information about other products and activities of the National Academies, please visit www.nationalacademies.org/about/whatwedo. PREPUBLICATION COPY – SUBJECT TO FURTHER EDITORIAL CORRECTION COMMITTEE ON ASTROBIOLOGY SCIENCE STRATEGY FOR THE SEARCH FOR LIFE IN THE UNIVERSE BARBARA SHERWOOD LOLLAR, C.C., FRSC,1 University of Toronto , Chair SUSHIL K. ATREYA, University of Michigan ALAN P. BOSS, Carnegie Institution of Washington PAUL G. FALKOWSKI, NAS,2 Rutgers, The State University of New Jersey, New Brunswick JACK D. FARMER, Arizona State University OLIVIER GUYON, University of Arizona GERALD F. JOYCE, NAS/NAM,3Salk Institute for Biological Studies JAMES F. KASTING, NAS, Pennsylvania State University VICTORIA S. MEADOWS, University of Washington PHILIP M. NECHES, NAE,4 Entrepreneurs Roundtable Accelerator CARL B. PILCHER, Blue Marble Space Institute of Science NILTON O. RENNO, University of Michigan KARYN L. ROGERS, Rensselaer Polytechnic Institute BRITNEY E. SCHMIDT, Georgia Institute of Technology ROGER SUMMONS, Massachusetts Institute of Technology FRANCES WESTALL, Centre National de la Recherche Scientifique SHELLEY A. WRIGHT, University of San Diego Staff DAVID H. SMITH, Senior Program Officer, Study Director SARAH C. BROTHERS, Associate Program Officer ANESIA WILKS, Program Coordinator MIA BROWN, Research Associate LAURA CUMMINGS, Lloyd V. Berkner Space Policy Intern CARSON BULLOCK, Lloyd V. Berkner Space Policy Intern 1 FRSC, Fellow, Royal Society of Canada. 2 NAS, Member, National Academy of Sciences. 3 NAM, Member, National Academy of Medicine. 4 NAE, Member, National Academy of Engineering. PREPUBLICATION COPY – SUBJECT TO FURTHER EDITORIAL CORRECTION v SPACE STUDIES BOARD FIONA HARRISON, NAS, California Institute of Technology, Chair ROBERT D. BRAUN, NAE, University of Colorado, Boulder, Vice Chair JAMES G. ANDERSON, NAS, Harvard University JEFF M. BINGHAM, Consultant JAY C. BUCKEY, Geisel School of Medicine at Dartmouth ADAM S. BURROWS, NAS, Princeton University MARY LYNNE DITTMAR, Dittmar Associates, Inc. JOSEPH FULLER, JR., Futron Corporation THOMAS R. GAVIN, California Institute of Technology SARAH GIBSON, National Center for Atmospheric Research VICTORIA E. HAMILTON, Southwest Research Institute ANTHONY C. JANETOS, Boston University CHRYSSA KOUVELIOTOU, NAS, The George Washington University DENNIS P. LETTENMAIER, NAE, University of California, Los Angeles ROSALY M. LOPES, Jet Propulsion Laboratory DAVID J. McCOMAS, Princeton University LARRY PAXTON, Johns Hopkins University, Applied Physics Laboratory ELIOT QUATAERT, University of California, Berkeley BARBARA SHERWOOD LOLLAR, University of Toronto HARLAN E. SPENCE, University of New Hampshire MARK THIEMENS, NAS, University of California, San Diego EDWARD L. WRIGHT, NAS, University of California, Los Angeles Staff MICHAEL H. MOLONEY, Director (until March 2, 2018) RICHARD ROWBERG, Interim Director (after March 2, 2018) CARMELA J. CHAMBERLAIN, Administrative Coordinator TANJA PILZAK, Manager, Program Operations CELESTE A. NAYLOR, Information Management Associate MARGARET KNEMEYER, Financial Officer PREPUBLICATION COPY – SUBJECT TO FURTHER EDITORIAL CORRECTION vi Preface Astrobiology is the study of the origin, evolution, distribution, and future of life in the universe. It is an inherently interdisciplinary field that encompasses astronomy, biology, geology, heliophysics, and planetary science, including complementary laboratory activities and field studies conducted in a wide range of terrestrial environments. Combining inherent scientific interest and public appeal, the search for life in the solar system and beyond provides a scientific rationale for many current and future activities carried out by the National Aeronautics and Science Administration (NASA) and other national and international agencies and organizations. In 2017, Congress directed NASA to enter into an arrangement with the National Academies of Sciences, Engineering, and Medicine to develop a science strategy for astrobiology that would outline key scientific questions, identify the most promising research in the field, and indicate the extent to which the mission priorities in existing decadal surveys address the search for life’s origin, evolution, distribution, and future in the universe (see Appendix A). In response to this congressional mandate, NASA’s associate administrator for the Science Mission Directorate approached the Space Studies Board (SSB) with a request to carry out this study (Appendix B). While retaining the core language of the law, the statement of task ultimately agreed upon between SSB and NASA incorporated additional tasks relating to the specific programmatic and scientific context of the agency’s various astrobiology-related endeavors, which are most prominently detailed in the 2015 NASA Astrobiology Strategy.1 Indeed, both the SSB and NASA regarded the nature and timing of the request to be particularly fortuitous in that the results of the study would provide important input to the next decadal surveys in astronomy and astrophysics and planetary sciences, due to start in 2018 and
Load more

Recommended publications
  • SETI Is Part of Astrobiology
    SETI is Part of Astrobiology Jason T. Wright Department of Astronomy & Physics Center for Exoplanets and Habitable Worlds Penn State University Phone: (814) 863-8470 [email protected] I. SETI is Part of Astrobiology “Traditional SETI is not part of astrobiology” declares the NASA Astrobiology Strategy 2015 document (p. 150). This is incorrect.1 Astrobiology is the study of life in the universe, in particular its “origin, evolution, distribution, and future in the universe.” [emphasis mine] Searches for biosignatures are searches for the results of interactions between life and its environment, and could be sensitive to even primitive life on other worlds. As such, these searches focus on the origin and evolution of life, using past life on Earth as a guide. But some of the most obvious ways in which Earth is inhabited today are its technosignatures such as radio transmissions, alterations of its atmosphere by industrial pollutants, and probes throughout the Solar System. It seems clear that the future of life on Earth includes the development of ever more obvious technosignatures. Indeed, the NASA Astrobiology Strategy 2015 document acknowledges “the possibility” that such technosignatures exist, but erroneously declares them to be “not part of contemporary SETI,” and mentions them only to declare that we should “be aware of the possibility” and to “be sure to include [technosignatures] as a possible kind of interpretation we should consider as we begin to get data on the exoplanets.” In other words, while speculation on the nature of biosignatures and the design of multi-billion dollar missions to find those signatures is consistent with NASA’s vision for astrobiology, speculation on the nature of technosignatures and the design of observations to find them is not.
    [Show full text]
  • Lecture-29 (PDF)
    Life in the Universe Orin Harris and Greg Anderson Department of Physics & Astronomy Northeastern Illinois University Spring 2021 c 2012-2021 G. Anderson., O. Harris Universe: Past, Present & Future – slide 1 / 95 Overview Dating Rocks Life on Earth How Did Life Arise? Life in the Solar System Life Around Other Stars Interstellar Travel SETI Review c 2012-2021 G. Anderson., O. Harris Universe: Past, Present & Future – slide 2 / 95 Dating Rocks Zircon Dating Sedimentary Grand Canyon Life on Earth How Did Life Arise? Life in the Solar System Life Around Dating Rocks Other Stars Interstellar Travel SETI Review c 2012-2021 G. Anderson., O. Harris Universe: Past, Present & Future – slide 3 / 95 Zircon Dating Zircon, (ZrSiO4), minerals incorporate trace amounts of uranium but reject lead. Naturally occuring uranium: • U-238: 99.27% • U-235: 0.72% Decay chains: • 238U −→ 206Pb, τ =4.47 Gyrs. • 235U −→ 207Pb, τ = 704 Myrs. 1956, Clair Camron Patterson dated the Canyon Diablo meteorite: τ =4.55 Gyrs. c 2012-2021 G. Anderson., O. Harris Universe: Past, Present & Future – slide 4 / 95 Dating Sedimentary Rocks • Relative ages: Deeper layers were deposited earlier • Absolute ages: Decay of radioactive isotopes old (deposited last) oldest (depositedolder first) c 2012-2021 G. Anderson., O. Harris Universe: Past, Present & Future – slide 5 / 95 Grand Canyon: Earth History from 200 million - 2 billion yrs ago. Dating Rocks Life on Earth Earth History Timeline Late Heavy Bombardment Hadean Shark Bay Stromatolites Cyanobacteria Q: Earliest Fossils? Life on Earth O2 History Q: Life on Earth How Did Life Arise? Life in the Solar System Life Around Other Stars Interstellar Travel SETI Review c 2012-2021 G.
    [Show full text]
  • The Eastern Outlet of Valles Marineris: a Window Into the Ancient Geologic and Hydrologic Evolution of Mars
    First Landing Site/Exploration Zone Workshop for Human Missions to the Surface of Mars (2015) 1054.pdf The Eastern Outlet of Valles Marineris: A Window into the Ancient Geologic and Hydrologic Evolution of Mars Stephen M. Clifford, David A. Kring, and Allan H. Treiman, Lunar and Planetary Institute/USRA, 3600 Bay Area Bvld., Houston, TX 77058 Over its 3,500 km length, Valles Marineris exhibits enormous range of geologic and environmental diversity. At its western end, the canyon is dominated by the tectonic complex of Noctis Labyrinthus while, in the east, it grades into an extensive region of chaos - where scoured channels and streamlined islands provide evidence of catastrophic floods that spilled into the northern plains [1-4]. In the central portion of the system, debris derived from the massive interior layered deposits of Candor, Ophir and Hebes Chasmas spills into the central trough have been identified as possible lucustrine sediments that may have been laid down in long-standing ice-covered lakes [3-6]. The potential survival and growth of Martian organisms in such an environment, or in the aquifers whose disruption gave birth to the chaotic terrain at the east end of the canyon, raises the possibility that fossil indicators of life may be present in the local sediment and rock. In other areas, 6 km-deep exposures of Hesperian and Noachian-age canyon wall stratigraphy have collapsed in massive landslides that extend many tens of kilometers across the canyon floor. Ejecta from interior craters, aeolian sediments, and possible volcanics (which appear to have emanated from structurally controlled vents along the base of the scarps), further contribute to the canyon's geologic complexity [2,3].
    [Show full text]
  • The Copernican Principle Rules out BLC1 As a Technological Radio Signal from the Alpha Centauri System
    Draft version January 13, 2021 Typeset using LATEX twocolumn style in AASTeX62 The Copernican Principle Rules Out BLC1 as a Technological Radio Signal from the Alpha Centauri System Amir Siraj1 and Abraham Loeb1 1Department of Astronomy, Harvard University, 60 Garden Street, Cambridge, MA 02138, USA ABSTRACT Without evidence for occupying a special time or location, we should not assume that we inhabit privileged circumstances in the Universe. As a result, within the context of all Earth-like planets orbiting Sun-like stars, the origin of a technological civilization on Earth should be considered a single outcome of a random process. We show that in such a Copernican framework, which is inherently optimistic about the prevalence of life in the Universe, the likelihood of the nearest star system, Alpha Centauri, hosting a radio-transmitting civilization is ∼ 10−8. This rules out, a priori, Breakthrough Listen Candidate 1 (BLC1) as a technological radio signal from the Alpha Centauri system, as such a scenario would violate the Copernican principle by about eight orders of magnitude. We also show that the Copernican principle is consistent with the vast majority of Fast Radio Bursts being natural in origin. Keywords: technosignatures; astrobiology; search for extraterrestrial intelligence; biosignatures 1. INTRODUCTION lihood of searches for primitive and intelligent life, us- The Copernican principle asserts that we are not priv- ing a Drake-type approach. Westby & Conselice(2020) ileged observers of the Universe. Successes of its appli- applied the Copernican principle to the search for intel- cation include the rejection of Ptolemaic geocentrism ligent life, but in forms that featured strict boundaries and the adoption of the modern cosmological princi- in time, thereby not reflecting a truly random process.
    [Show full text]
  • Astrobiology and the Search for Life Beyond Earth in the Next Decade
    Astrobiology and the Search for Life Beyond Earth in the Next Decade Statement of Dr. Andrew Siemion Berkeley SETI Research Center, University of California, Berkeley ASTRON − Netherlands Institute for Radio Astronomy, Dwingeloo, Netherlands Radboud University, Nijmegen, Netherlands to the Committee on Science, Space and Technology United States House of Representatives 114th United States Congress September 29, 2015 Chairman Smith, Ranking Member Johnson and Members of the Committee, thank you for the opportunity to testify today. Overview Nearly 14 billion years ago, our universe was born from a swirling quantum soup, in a spectacular and dynamic event known as the \big bang." After several hundred million years, the first stars lit up the cosmos, and many hundreds of millions of years later, the remnants of countless stellar explosions coalesced into the first planetary systems. Somehow, through a process still not understood, the laws of physics guiding the unfolding of our universe gave rise to self-replicating organisms − life. Yet more perplexing, this life eventually evolved a capacity to know its universe, to study it, and to question its own existence. Did this happen many times? If it did, how? If it didn't, why? SETI (Search for ExtraTerrestrial Intelligence) experiments seek to determine the dis- tribution of advanced life in the universe through detecting the presence of technology, usually by searching for electromagnetic emission from communication technology, but also by searching for evidence of large scale energy usage or interstellar propulsion. Technology is thus used as a proxy for intelligence − if an advanced technology exists, so to does the ad- vanced life that created it.
    [Show full text]
  • Tiny ASTERIA Satellite Achieves a First for Cubesats 16 August 2018, by Lauren Hinkel and Mary Knapp
    Tiny ASTERIA satellite achieves a first for CubeSats 16 August 2018, by Lauren Hinkel And Mary Knapp The ASTERIA project is a collaboration between MIT and NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, funded through JPL's Phaeton Program. The project started in 2010 as an undergraduate class project in 16.83/12.43 (Space Systems Engineering), involving a technology demonstration of astrophysical measurements using a Cubesat, with a primary goal of training early-career engineers. The ASTERIA mission—of which Department of Earth, Atmospheric and Planetary Sciences Class of 1941 Professor of Planetary Sciences Sara Seager is the Principal Investigator—was designed to demonstrate key technologies, including very Members of the ASTERIA team prepare the petite stable pointing and thermal control for making satellite for its journey to space. Credit: NASA/JPL- extremely precise measurements of stellar Caltech brightness in a tiny satellite. Earlier this year, ASTERIA achieved pointing stability of 0.5 arcseconds and thermal stability of 0.01 degrees Celsius. These technologies are important for A miniature satellite called ASTERIA (Arcsecond precision photometry, i.e., the measurement of Space Telescope Enabling Research in stellar brightness over time. Astrophysics) has measured the transit of a previously-discovered super-Earth exoplanet, 55 Cancri e. This finding shows that miniature satellites, like ASTERIA, are capable of making of sensitive detections of exoplanets via the transit method. While observing 55 Cancri e, which is known to transit, ASTERIA measured a miniscule change in brightness, about 0.04 percent, when the super- Earth crossed in front of its star. This transit measurement is the first of its kind for CubeSats (the class of satellites to which ASTERIA belongs) which are about the size of a briefcase and hitch a ride to space as secondary payloads on rockets used for larger spacecraft.
    [Show full text]
  • From Hayabusa to Hayabusa2: Present Status and Plans for Sample Curations of Asteroidal Sample Return Missions by Jaxa
    81st Annual Meeting of The Meteoritical Society 2018 (LPI Contrib. No. 2067) 6117.pdf FROM HAYABUSA TO HAYABUSA2: PRESENT STATUS AND PLANS FOR SAMPLE CURATIONS OF ASTEROIDAL SAMPLE RETURN MISSIONS BY JAXA. T. Yada1, K. Sakamoto1, M. Yoshitake1, K. Kumagai2, M. Nishimura2, Y. Nakano1, S. Furuya1, M. Abe1, T. Okada1, S. Tachibana3, H. Yurimoto1,4, and M. Fujimoto1,5, 1Astromat. Sci. Res. Group, Inst. Space Astronaut. Sci., Japan Aerosp. Explor. Agnecy, 3-1-1 Yoshinodai, Chuo, Sagamihara, Kanagawa 252-5210, Japan ([email protected]), 2 Marine Works Japan Ltd., 3-54-1 Oppamahigashi, Yokosuka 237-0063 Japan, 3Dept. Earth Planet. Sci., Grad. Sch. Science, Univ. Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan, 4Dept. Earth Science, Grad. Sch. Science, Hokkaido Univ., Kita 8, Nishi 5, Kita, Sapporo, Hokkaido 060-0808, Japan, 5Earth-Life Sci. Inst., Tokyo Inst. Tech., 2-12-1-1E-1 Ookayama, Meguro, Tokyo 152-8550, Japan. Introduction: The new era of sample return missions had started since the Stardust returned samples from com- et 81P/Wild 2 in 2006 [1], followed by the Hayabusa spacecraft from the near-Earth S-type asteroid 25143 Itokawa in 2010 [2,3]. In this year, Hayabusa2 will reach its target body, the near-Earth C-type asteroid 162173 Ryugu [4], and also OSIRIS-REx toward the near-Earth B-type asteroid 101955 Bennu [5]. Additionally, several other sample return missions have been planned recently, such as the Martian Moons eXplorer (MMX) for the Phobos and/or Deimos [6], the CAESAR for 67P/Churyumov-Gerasimenko [7], and the HELACLES for the the Moon [8].
    [Show full text]
  • Monday, November 13, 2017 WHAT DOES IT MEAN to BE HABITABLE? 8:15 A.M. MHRGC Salons ABCD 8:15 A.M. Jang-Condell H. * Welcome C
    Monday, November 13, 2017 WHAT DOES IT MEAN TO BE HABITABLE? 8:15 a.m. MHRGC Salons ABCD 8:15 a.m. Jang-Condell H. * Welcome Chair: Stephen Kane 8:30 a.m. Forget F. * Turbet M. Selsis F. Leconte J. Definition and Characterization of the Habitable Zone [#4057] We review the concept of habitable zone (HZ), why it is useful, and how to characterize it. The HZ could be nicknamed the “Hunting Zone” because its primary objective is now to help astronomers plan observations. This has interesting consequences. 9:00 a.m. Rushby A. J. Johnson M. Mills B. J. W. Watson A. J. Claire M. W. Long Term Planetary Habitability and the Carbonate-Silicate Cycle [#4026] We develop a coupled carbonate-silicate and stellar evolution model to investigate the effect of planet size on the operation of the long-term carbon cycle, and determine that larger planets are generally warmer for a given incident flux. 9:20 a.m. Dong C. F. * Huang Z. G. Jin M. Lingam M. Ma Y. J. Toth G. van der Holst B. Airapetian V. Cohen O. Gombosi T. Are “Habitable” Exoplanets Really Habitable? A Perspective from Atmospheric Loss [#4021] We will discuss the impact of exoplanetary space weather on the climate and habitability, which offers fresh insights concerning the habitability of exoplanets, especially those orbiting M-dwarfs, such as Proxima b and the TRAPPIST-1 system. 9:40 a.m. Fisher T. M. * Walker S. I. Desch S. J. Hartnett H. E. Glaser S. Limitations of Primary Productivity on “Aqua Planets:” Implications for Detectability [#4109] While ocean-covered planets have been considered a strong candidate for the search for life, the lack of surface weathering may lead to phosphorus scarcity and low primary productivity, making aqua planet biospheres difficult to detect.
    [Show full text]
  • Pre-Vetted False Positives for TESS
    Swarthmore College Works Physics & Astronomy Faculty Works Physics & Astronomy 11-1-2018 The KELT Follow-Up Network And Transit False-Positive Catalog: Pre-Vetted False Positives For TESS K. A. Collins K. I. Collins FJ.ollow Pepper this and additional works at: https://works.swarthmore.edu/fac-physics J. Labadie-Bar Part of the Astrtz ophysics and Astronomy Commons Let us know how access to these works benefits ouy K. G. Stassun See next page for additional authors Recommended Citation K. A. Collins, K. I. Collins, J. Pepper, J. Labadie-Bartz, K. G. Stassun, B. S. Gaudi, D. Bayliss, J. Bento, K. D. Colón, D. Feliz, D. James, M. C. Johnson, R. B. Kuhn, M. B. Lund, M. T. Penny, J. E. Rodriguez, R. J. Siverd, D. J. Stevens, X. Yao, G. Zhou, M. Akshay, G. F. Aldi, C. Ashcraft, S. Awiphan, Ö. Baştürk, D. Baker, T. G. Beatty, P. Benni, P. Berlind, G. B. Berriman, Z. Berta-Thompson, A. Bieryla, V. Bozza, S. C. Novati, M. L. Calkins, J. M. Cann, D. R. Ciardi, W. D. Cochran, David H. Cohen, D. Conti, J. R. Crepp, I. A. Curtis, G. D'Ago, K. A. Diazeguigure, C. D. Dressing, F. Dubois, E. Ellington, T. G. Ellis, G. A. Esquerdo, P. Evans, A. Friedli, A. Fukui, B. J. Fulton, E. J. Gonzales, J. C. Good, J. Gregorio, T. Gumusayak, D. A. Hancock, C. K. Harada, R. Hart, E. G. Hintz, H. Jang-Condell, E. J. Jeffery, Eric L.N. Jensen, E. Jofré, M. D. Joner, A. Kar, D. H. Kasper, B. Keten, J.
    [Show full text]
  • A Comparative Analysis of the Cobb-Douglas Habitability Score (CDHS) with the Earth Similarity Index (ESI)
    A Comparative Analysis of the Cobb-Douglas Habitability Score (CDHS) with the Earth Similarity Index (ESI) Surbhi Agrawal1, Suryoday Basak1, Snehanshu Saha1, Kakoli Bora2 and Jayant Murthy3 I. Introduction and Methods is 1.27 EU, the radius is R = M 0.5 ≡ 1.12 EU1. Accordingly, the escape velocity was calculated by V = p2GM/R ≡ 1.065 (EU), and the density by A sequence of recent explorations by Saha et al. [4] e the usual D = 3M/4πR3 ≡ 0.904 (EU) formula. expanding previous work by Bora et al. [1] on using The manuscript, [4] consists of three related Machine Learning algorithm to construct and test analyses: (i) computation and comparison of ESI planetary habitability functions with exoplanet data and CDHS habitability scores for Proxima-b and raises important questions. The 2018 paper analyzed the Trappist-1 system, (ii) some considerations the elasticity of their Cobb-Douglas Habitability on the computational methods for computing the Score (CDHS) and compared its performance with CDHS score, and (iii) a machine learning exercise other machine learning algorithms. They demon- to estimate temperature-based habitability classes. strated the robustness of their methods to identify The analysis is carefully conducted in each case, potentially habitable planets from exoplanet dataset. and the depth of the contribution to the literature Given our little knowledge on exoplanets and habit- helped unfold the differences and approaches to ability, these results and methods provide one impor- CDHS and ESI. tant step toward automatically identifying objects of interest from large datasets by future ground and Several important characteristics were introduced space observatories.
    [Show full text]
  • Enceladus Life Finder: the Search for Life in a Habitable Moon
    Geophysical Research Abstracts Vol. 17, EGU2015-14923, 2015 EGU General Assembly 2015 © Author(s) 2015. CC Attribution 3.0 License. Enceladus life finder: the search for life in a habitable moon. Jonathan Lunine (1), Hunter Waite (2), Frank Postberg (3), Linda Spilker (4), and Karla Clark (4) (1) Center for Radiophysics and Space Research, Cornell University, Ithaca ([email protected]), (2) Southwest Research Institute,San Antonio, ( [email protected]), (3) U. Stuttgart, Stuttgart, ([email protected]), (4) Jet Propulsion Laboratory, Pasadena CA 91125, ( [email protected]) Is there life elsewhere in the solar system? Guided by the principle that we can most easily recognize life as we know it—life that requires liquid water—Enceladus is particularly attractive because liquid water from its deep interior is actively erupting into space, making sampling of the interior straightforward. The Cassini Saturn Orbiter has provided the motivation. In particular, at high resolution, spatial coincidences between individual geysers and small-scale hot spots revealed the liquid reservoir supplying the eruptions to be not in the near-surface but deeper within the moon [1], putting on a firm foundation the principle that sampling the plume allows us to know the composition of the ocean. Sensitive gravity and topography measurements established the location and dimensions of that reservoir: ∼ 35 km beneath the SPT ice shell and extending out to at least 50 degrees latitude, implying an interior ocean large enough to have been stable over geologic time [2]. The Cassini ion neutral mass spectrometer (INMS) discovered organic and nitrogen-bearing molecules in the plume vapour, and the Cosmic Dust Analyser (CDA) detected salts in the plume icy grains, arguing strongly for ocean water being in con-tact with a rocky core [3], [4].
    [Show full text]
  • Exoplanet Community Report
    JPL Publication 09‐3 Exoplanet Community Report Edited by: P. R. Lawson, W. A. Traub and S. C. Unwin National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California March 2009 The work described in this publication was performed at a number of organizations, including the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (NASA). Publication was provided by the Jet Propulsion Laboratory. Compiling and publication support was provided by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not constitute or imply its endorsement by the United States Government, or the Jet Propulsion Laboratory, California Institute of Technology. © 2009. All rights reserved. The exoplanet community’s top priority is that a line of probe­class missions for exoplanets be established, leading to a flagship mission at the earliest opportunity. iii Contents 1 EXECUTIVE SUMMARY.................................................................................................................. 1 1.1 INTRODUCTION...............................................................................................................................................1 1.2 EXOPLANET FORUM 2008: THE PROCESS OF CONSENSUS BEGINS.....................................................2
    [Show full text]