DOCSLIB.ORG

PS4: Biosignature Modification in the Oxia Planum Region

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
PS4: Biosignature Modification in the Oxia Planum Region Biosignature modification in the Oxia Planum region. Supervision team: Victoria Pearson, Nisha Ramkissoon, Peter Fawdon and Manish Patel External collaborator: Andrew Coates (UCL), Matt Gunn (Aberystwyth University), Ian Hutchinson (University of Leicester) Lead contact: Victoria Pearson [email protected] Description: ESA’s ExoMars 2020 Rosalind Franklin rover is expected to land on Mars in mid-2021, with a primary objective to search for signs of life. A landing site, Oxia Planum, has been selected that is rich in clay minerals, indicative of an environment that has been subjected to aqueous alteration in the past [1-3]. The prior presence of water may indicate that this region was once habitable, but any biosignatures (geochemical indicators for life) left behind may have been modified or even obliterated by subsequent surface processing, such as impact cratering, desiccation and diagenetic aqueous alteration [4]. This project aims to determine the effects of such processing on biosignatures within an Oxia Planum-like environment. It will combine orbital and rover data to develop an Oxia Planum simulant, which will then be used in laboratory simulation experiments to identify how biosignatures could be modified after they experience the types of processing seen at Oxia Planum. The project will begin with the design and production of a prototype Oxia Planum simulant based on existing data obtained from orbiting spacecraft. This prototype will be characterised and tested using instruments akin to those onboard the rover, specifically the Raman Laser Spectrometer (RLS) and infrared spectrometer for ExoMars (ISEM). Once data is returned from the ISEM, RLS and MicrOMEGA (micro Observatoire pour la Minéralogie l’Eau, la Glace et l’Activite) instruments aboard the ExoMars rover, the simulant will be refined, and a final version produced. The simulant will then be doped or loaded with biosignatures, defined from literature data from existing Mars missions [5] or returned data from ExoMars 2020 rover. It will then be subjected to secondary processing to recreate high pressure and temperature environments that result from impacts. These environments have been shown to cause the degradation of organic molecules, for example long chain hydrocarbons, that are associated with microbial life [6]. These processed samples will then be re-analysed using instruments similar to the those aboard the Rover. The results from this work will help with the interpretation of data returned from the rover and future missions. References: [1] Quantin-Nataf, C. et al. (2018) “The unique and diverse record of Noachian aqueous activity in Oxia Planum, Mars,” in Lunar and Planetary Science Conference, Abstract# 2562. [2] Carter, J. et al. (2016) “Oxia Planum, a clay-laden landing site proposed for the Exomars rover mission: aqueous mineralogy and alteration scenarios.” in Lunar and Planetary Science Conference, Abstract# 2062. [3] Vago, J. L., et al. (2017) Habitability on early Mars and the search for biosignatures with the ExoMars rover, Astrobiology, vol. 17, no. 6–7, pp. 471–510. [4] Quantin-Nataf, C., et al. (2019) ExoMars at Oxia Planum, probing the aqueous-related Noachian environments. 2019, In Prep [5] Eigenbrode, J. L., et al. (2018) Organic matter preserved in 3-billion-year-old mudstones at Gale crater, Mars, Science, no. June, pp. 1–6. [6] W. Montgomery, G. D. Bromiley, and M. A. Sephton (2016) The nature of organic records in impact excavated rocks on Mars, Scientific Reports, vol. 6, Aug. Qualifications required: The ideal candidates will have a minimum 2:1 in geological sciences, geochemistry or a related discipline. .
Load more

Recommended publications
  • Water, Habitability, and Detectability Steve Desch
    Water, Habitability, and Detectability Steve Desch PI, “Exoplanetary Ecosystems” NExSS team School of Earth and Space Exploration, Arizona State University with Ariel Anbar, Tessa Fisher, Steven Glaser, Hilairy Hartnett, Stephen Kane, Susanne Neuer, Cayman Unterborn, Sara Walker, Misha Zolotov Astrobiology Science Strategy NAS Committee, Beckmann Center, Irvine, CA (remotely), January 17, 2018 How to look for life on (Earth-like) exoplanets: find oxygen in their atmospheres How Earth-like must an exoplanet be for this to work? Seager et al. (2013) How to look for life on (Earth-like) exoplanets: find oxygen in their atmospheres Oxygen on Earth overwhelmingly produced by photosynthesizing life, which taps Sun’s energy and yields large disequilibrium signature. Caveats: Earth had life for billions of years without O2 in its atmosphere. First photosynthesis to evolve on Earth was anoxygenic. Many ‘false positives’ recognized because O2 has abiotic sources, esp. photolysis (Luger & Barnes 2014; Harman et al. 2015; Meadows 2017). These caveats seem like exceptions to the ‘rule’ that ‘oxygen = life’. How non-Earth-like can an exoplanet be (especially with respect to water content) before oxygen is no longer a biosignature? Part 1: How much water can terrestrial planets form with? Part 2: Are Aqua Planets or Water Worlds habitable? Can we detect life on them? Part 3: How should we look for life on exoplanets? Part 1: How much water can terrestrial planets form with? Theory says: up to hundreds of oceans’ worth of water Trappist-1 system suggests hundreds of oceans, especially around M stars Many (most?) planets may be Aqua Planets or Water Worlds How much water can terrestrial planets form with? Earth- “snow line” Standard Sun distance models of distance accretion suggest abundant water.
    [Show full text]
  • Mawrth Vallis, Mars: a Fascinating Place for Future in Situ Exploration
    Mawrth Vallis, Mars: a fascinating place for future in situ exploration François Poulet1, Christoph Gross2, Briony Horgan3, Damien Loizeau1, Janice L. Bishop4, John Carter1, Csilla Orgel2 1Institut d’Astrophysique Spatiale, CNRS/Université Paris-Sud, 91405 Orsay Cedex, France 2Institute of Geological Sciences, Planetary Sciences and Remote Sensing Group, Freie Universität Berlin, Germany 3Purdue University, West Lafayette, USA. 4SETI Institute/NASA-ARC, Mountain View, CA, USA Corresponding author: François Poulet, IAS, Bâtiment 121, CNRS/Université Paris-Sud, 91405 Orsay Cedex, France; email: [email protected] Running title: Mawrth: a fascinating place for exploration 1 Abstract After the successful landing of the Mars Science Laboratory rover, both NASA and ESA initiated a selection process for potential landing sites for the Mars2020 and ExoMars missions, respectively. Two ellipses located in the Mawrth Vallis region were proposed and evaluated during a series of meetings (3 for Mars2020 mission and 5 for ExoMars). We describe here the regional context of the two proposed ellipses as well as the framework of the objectives of these two missions. Key science targets of the ellipses and their astrobiological interests are reported. This work confirms the proposed ellipses contain multiple past Martian wet environments of subaerial, subsurface and/or subaqueous character, in which to probe the past climate of Mars, build a broad picture of possible past habitable environments, evaluate their exobiological potentials and search for biosignatures in well-preserved rocks. A mission scenario covering several key investigations during the nominal mission of each rover is also presented, as well as descriptions of how the site fulfills the science requirements and expectations of in situ martian exploration.
    [Show full text]
  • Atmospheric Dust on Mars: a Review
    47th International Conference on Environmental Systems ICES-2017-175 16-20 July 2017, Charleston, South Carolina Atmospheric Dust on Mars: A Review François Forget1 Laboratoire de Météorologie Dynamique (LMD/IPSL), Sorbonne Universités, UPMC Univ Paris 06, PSL Research University, Ecole Normale Supérieure, Université Paris-Saclay, Ecole Polytechnique, CNRS, Paris, France Luca Montabone2 Laboratoire de Météorologie Dynamique (LMD/IPSL), Paris, France & Space Science Institute, Boulder, CO, USA The Martian environment is characterized by airborne mineral dust extending between the surface and up to 80 km altitude. This dust plays a key role in the climate system and in the atmospheric variability. It is a significant issue for any system on the surface. The atmospheric dust content is highly variable in space and time. In the past 20 years, many investigations have been conducted to better understand the characteristics of the dust particles, their distribution and their variability. However, many unknowns remain. The occurrence of local, regional and global-scale dust storms are better documented and modeled, but they remain very difficult to predict. The vertical distribution of dust, characterized by detached layers exhibiting large diurnal and seasonal variations, remains quite enigmatic and very poorly modeled. Nomenclature Ls = Solar Longitude (°) MY = Martian year reff = Effective radius τ = Dust optical depth (or dust opacity) CDOD = Column Dust Optical Depth (i.e. τ integrated over the atmospheric column) IR = Infrared LDL = Low Dust Loading (season) HDL = High Dust Loading (season) MGS = Mars Global Surveyor (NASA spacecraft) MRO = Mars Reconnaissance Orbiter (NASA spacecraft) MEX = Mars Express (ESA spacecraft) TES = Thermal Emission Spectrometer (instrument aboard MGS) THEMIS = Thermal Emission Imaging System (instrument aboard NASA Mars Odyssey spacecraft) MCS = Mars Climate Sounder (instrument aboard MRO) PDS = Planetary Data System (NASA data archive) EDL = Entry, Descending, and Landing GCM = Global Climate Model I.
    [Show full text]
  • Biosignatures Search in Habitable Planets
    galaxies Review Biosignatures Search in Habitable Planets Riccardo Claudi 1,* and Eleonora Alei 1,2 1 INAF-Astronomical Observatory of Padova, Vicolo Osservatorio, 5, 35122 Padova, Italy 2 Physics and Astronomy Department, Padova University, 35131 Padova, Italy * Correspondence: [email protected] Received: 2 August 2019; Accepted: 25 September 2019; Published: 29 September 2019 Abstract: The search for life has had a new enthusiastic restart in the last two decades thanks to the large number of new worlds discovered. The about 4100 exoplanets found so far, show a large diversity of planets, from hot giants to rocky planets orbiting small and cold stars. Most of them are very different from those of the Solar System and one of the striking case is that of the super-Earths, rocky planets with masses ranging between 1 and 10 M⊕ with dimensions up to twice those of Earth. In the right environment, these planets could be the cradle of alien life that could modify the chemical composition of their atmospheres. So, the search for life signatures requires as the first step the knowledge of planet atmospheres, the main objective of future exoplanetary space explorations. Indeed, the quest for the determination of the chemical composition of those planetary atmospheres rises also more general interest than that given by the mere directory of the atmospheric compounds. It opens out to the more general speculation on what such detection might tell us about the presence of life on those planets. As, for now, we have only one example of life in the universe, we are bound to study terrestrial organisms to assess possibilities of life on other planets and guide our search for possible extinct or extant life on other planetary bodies.
    [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]
  • March 21–25, 2016
    FORTY-SEVENTH LUNAR AND PLANETARY SCIENCE CONFERENCE PROGRAM OF TECHNICAL SESSIONS MARCH 21–25, 2016 The Woodlands Waterway Marriott Hotel and Convention Center The Woodlands, Texas INSTITUTIONAL SUPPORT Universities Space Research Association Lunar and Planetary Institute National Aeronautics and Space Administration CONFERENCE CO-CHAIRS Stephen Mackwell, Lunar and Planetary Institute Eileen Stansbery, NASA Johnson Space Center PROGRAM COMMITTEE CHAIRS David Draper, NASA Johnson Space Center Walter Kiefer, Lunar and Planetary Institute PROGRAM COMMITTEE P. Doug Archer, NASA Johnson Space Center Nicolas LeCorvec, Lunar and Planetary Institute Katherine Bermingham, University of Maryland Yo Matsubara, Smithsonian Institute Janice Bishop, SETI and NASA Ames Research Center Francis McCubbin, NASA Johnson Space Center Jeremy Boyce, University of California, Los Angeles Andrew Needham, Carnegie Institution of Washington Lisa Danielson, NASA Johnson Space Center Lan-Anh Nguyen, NASA Johnson Space Center Deepak Dhingra, University of Idaho Paul Niles, NASA Johnson Space Center Stephen Elardo, Carnegie Institution of Washington Dorothy Oehler, NASA Johnson Space Center Marc Fries, NASA Johnson Space Center D. Alex Patthoff, Jet Propulsion Laboratory Cyrena Goodrich, Lunar and Planetary Institute Elizabeth Rampe, Aerodyne Industries, Jacobs JETS at John Gruener, NASA Johnson Space Center NASA Johnson Space Center Justin Hagerty, U.S. Geological Survey Carol Raymond, Jet Propulsion Laboratory Lindsay Hays, Jet Propulsion Laboratory Paul Schenk,
    [Show full text]
  • IS HABITABILITY CONSTRAINED by PHYSICS OR BIOLOGY? the CASE for a GAIAN BOTTLENECK. Charles. H. Lineweaver1 and Aditya Chopra1
    Astrobiology Science Conference 2015 (2015) 7276.pdf IS HABITABILITY CONSTRAINED BY PHYSICS OR BIOLOGY? THE CASE FOR A GAIAN BOTTLENECK. Charles. H. Lineweaver1 and Aditya Chopra1, 1Planetary Science Institute, Research School of Astronomy and Astrophysics and Research School of Earth Sciences, Australian National University, Australia, [email protected], [email protected] The prerequisites and ingredients for life seem to Earth. We are proposing a sequence of events that can be abundantly available in the universe. However, the be summarized as: (1) uninhabitably hot, high universe does not seem to be teeming with life. The bombardment rate during planetary accretion (2) most common explanation for this is a low probability cooler, reduced bombardment (3) emergence of life in for the emergence of life (an emergence bottleneck), planetary environments that tend to evolve away from notionally due to the intricacies of the molecular habitability, continuous volatile loss. Then either (4a) recipe. Here we present an alternative explanation: a the inability of life to control atmospheric volatiles and Gaian bottleneck [1]. If life emerges on a planet, it maintain habitabililty, thus leading to extinction (left only rarely evolves quickly enough to regulate panel in figure) or (4b) the rapid evolution of Gaian temperature through albedo and atmospheric volatiles regulation and the maintenance of habitability (right and maintain habitability. Such a Gaian bottleneck panel in figure) suggests that (i) extinction is the cosmic default for most life that has ever emerged on the surface of wet Gaian Regulation rocky planets in the universe and (ii) rocky planets +2 Gyr +2 Gyr need to be inhabited, to remain habitable.
    [Show full text]
  • Open Research Online Oro.Open.Ac.Uk
    Open Research Online The Open University’s repository of research publications and other research outputs Oxia Planum: The Landing Site for the ExoMars “Rosalind Franklin” Rover Mission: Geological Context and Prelanding Interpretation Journal Item How to cite: Quantin-Nataf, Cathy; Carter, John; Mandon, Lucia; Thollot, Patrick; Balme, Matthew; Volat, Matthieu; Pan, Lu; Loizeau, Damien; Millot, Cédric; Breton, Sylvain; Dehouck, Erwin; Fawdon, Peter; Gupta, Sanjeev; Davis, Joel; Grindrod, Peter M.; Pacifici, Andrea; Bultel, Benjamin; Allemand, Pascal; Ody, Anouck; Lozach, Loic and Broyer, Jordan (2021). Oxia Planum: The Landing Site for the ExoMars “Rosalind Franklin” Rover Mission: Geological Context and Prelanding Interpretation. Astrobiology, 21(3) For guidance on citations see FAQs. c 2020 Cathy Quantin-Nataf et al. https://creativecommons.org/licenses/by/4.0/ Version: Version of Record Link(s) to article on publisher’s website: http://dx.doi.org/doi:10.1089/ast.2019.2191 Copyright and Moral Rights for the articles on this site are retained by the individual authors and/or other copyright owners. For more information on Open Research Online’s data policy on reuse of materials please consult the policies page. oro.open.ac.uk ASTROBIOLOGY Volume 21, Number 3, 2021 Research Article Mary Ann Liebert, Inc. DOI: 10.1089/ast.2019.2191 Oxia Planum: The Landing Site for the ExoMars ‘‘Rosalind Franklin’’ Rover Mission: Geological Context and Prelanding Interpretation Cathy Quantin-Nataf,1 John Carter,2 Lucia Mandon,1 Patrick Thollot,1 Matthew Balme,3 Matthieu Volat,1 Lu Pan,1 Damien Loizeau,1,2 Ce´dric Millot,1 Sylvain Breton,1 Erwin Dehouck,1 Peter Fawdon,3 Sanjeev Gupta,4 Joel Davis,5 Peter M.
    [Show full text]
  • Blocks Size Frequency Distribution in the Enceladus Tiger Stripes Area: Implications on Their Formative Processes
    universe Article Blocks Size Frequency Distribution in the Enceladus Tiger Stripes Area: Implications on Their Formative Processes Maurizio Pajola 1,* , Alice Lucchetti 1 , Lara Senter 2 and Gabriele Cremonese 1 1 INAF-Astronomical Observatory of Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy; [email protected] (A.L.); [email protected] (G.C.) 2 Department of Physics and Astronomy “G. Galilei”, Università di Padova, 35122 Padova, Italy; [email protected] * Correspondence: [email protected] Abstract: We study the size frequency distribution of the blocks located in the deeply fractured, geologically active Enceladus South Polar Terrain with the aim to suggest their formative mechanisms. Through the Cassini ISS images, we identify ~17,000 blocks with sizes ranging from ~25 m to 366 m, and located at different distances from the Damascus, Baghdad and Cairo Sulci. On all counts and for both Damascus and Baghdad cases, the power-law fitting curve has an index that is similar to the one obtained on the deeply fractured, actively sublimating Hathor cliff on comet 67P/Churyumov- Gerasimenko, where several non-dislodged blocks are observed. This suggests that as for 67P, sublimation and surface stresses favor similar fractures development in the Enceladus icy matrix, hence resulting in comparable block disaggregation. A steeper power-law index for Cairo counts may suggest a higher degree of fragmentation, which could be the result of localized, stronger tectonic disruption of lithospheric ice. Eventually, we show that the smallest blocks identified are located Citation: Pajola, M.; Lucchetti, A.; from tens of m to 20–25 km from the Sulci fissures, while the largest blocks are found closer to the Senter, L.; Cremonese, G.
    [Show full text]
  • Exoplanet Biosignatures: a Review of Remotely Detectable Signs of Life
    ASTROBIOLOGY Volume 18, Number 6, 2018 Mary Ann Liebert, Inc. DOI: 10.1089/ast.2017.1729 Exoplanet Biosignatures: A Review of Remotely Detectable Signs of Life Edward W. Schwieterman,1–5 Nancy Y. Kiang,3,6 Mary N. Parenteau,3,7 Chester E. Harman,3,6,8 Shiladitya DasSarma,9,10 Theresa M. Fisher,11 Giada N. Arney,3,12 Hilairy E. Hartnett,11,13 Christopher T. Reinhard,4,14 Stephanie L. Olson,1,4 Victoria S. Meadows,3,15 Charles S. Cockell,16,17 Sara I. Walker,5,11,18,19 John Lee Grenfell,20 Siddharth Hegde,21,22 Sarah Rugheimer,23 Renyu Hu,24,25 and Timothy W. Lyons1,4 Abstract In the coming years and decades, advanced space- and ground-based observatories will allow an unprecedented opportunity to probe the atmospheres and surfaces of potentially habitable exoplanets for signatures of life. Life on Earth, through its gaseous products and reflectance and scattering properties, has left its fingerprint on the spectrum of our planet. Aided by the universality of the laws of physics and chemistry, we turn to Earth’s biosphere, both in the present and through geologic time, for analog signatures that will aid in the search for life elsewhere. Considering the insights gained from modern and ancient Earth, and the broader array of hypothetical exoplanet possibilities, we have compiled a comprehensive overview of our current understanding of potential exoplanet biosignatures, including gaseous, surface, and temporal biosignatures. We additionally survey biogenic spectral features that are well known in the specialist literature but have not yet been robustly vetted in the context of exoplanet biosignatures.
    [Show full text]
  • Rapid Single Image-Based DTM Estimation from Exomars TGO Cassis Images Using Generative Adversarial U-Nets
    remote sensing Article Rapid Single Image-Based DTM Estimation from ExoMars TGO CaSSIS Images Using Generative Adversarial U-Nets Yu Tao 1,* , Siting Xiong 2, Susan J. Conway 3, Jan-Peter Muller 1 , Anthony Guimpier 3, Peter Fawdon 4, Nicolas Thomas 5 and Gabriele Cremonese 6 1 Mullard Space Science Laboratory, Imaging Group, Department of Space and Climate Physics, University College London, Holmbury St Mary, Surrey RH5 6NT, UK; [email protected] 2 College of Civil and Transportation Engineering, Shenzhen University, Shenzhen 518060, China; [email protected] 3 Laboratoire de Planétologie et Géodynamique, CNRS, UMR 6112, Universités de Nantes, 44300 Nantes, France; [email protected] (S.J.C.); [email protected] (A.G.) 4 School of Physical Sciences, Open University, Walton Hall, Milton Keynes MK7 6AA, UK; [email protected] 5 Physikalisches Institut, Universität Bern, Sidlerstrasse 5, 3012 Bern, Switzerland; [email protected] 6 INAF, Osservatorio Astronomico di Padova, 35122 Padova, Italy; [email protected] * Correspondence: [email protected] Abstract: The lack of adequate stereo coverage and where available, lengthy processing time, various artefacts, and unsatisfactory quality and complexity of automating the selection of the best set of processing parameters, have long been big barriers for large-area planetary 3D mapping. In this paper, Citation: Tao, Y.; Xiong, S.; Conway, we propose a deep learning-based solution, called MADNet (Multi-scale generative Adversarial S.J.; Muller, J.-P.; Guimpier, A.; u-net with Dense convolutional and up-projection blocks), that avoids or resolves all of the above Fawdon, P.; Thomas, N.; Cremonese, G.
    [Show full text]
  • The Search for Biosignatures and Their Relationship to Complex Societies a Biosignature Denotes the Presence of a Substance Or P
    The Search for Biosignatures and Their Relationship to Complex Societies A biosignature denotes the presence of a substance or phenomenon that is indicative of life, past or present. Biosignature is a term defined in the context of the field of astrobiology and it represents evidence of life in the context of the system where it is being detected. More specifically, if this system is a planet or a moon, the biosignature represents the detection of chemical compounds on the surface or in the atmosphere (if it has an atmosphere) that are indicative of life on that planet or moon. For example, biosignatures can be chemical compounds, particularly organic compounds, visible macroscopic patterns, atmospheric gases. The past couple of decades have seen an explosion in biosignature science, but currently only the Viking mission has been equipped to search for biosignatures in our solar system. Upcoming missions target the moons Europa and Titan for searches. One of Earth’s biosignatures is the atmospheric composition of gases, particularly oxygen and methane in strong thermodynamic equilibrium, the surface reflectance of the vegetation in color red, and narrow-band, pulse modulated radio signs. These “signatures” together suggest an inhabited planet, but each signature by itself might be a “false positive” in confirming the presence of life. Additional to how we understand the presence of life on Earth as a starting point for biosignature searches on exoplanets, there has been considerable work done in understanding “agnostic biosignature”, or biosignatures that have very little in common with life on Earth. The agnostic biosignatures are based on a broader definition of life, based on processes and activities and not on specific molecular structures.
    [Show full text]