Exoplanet Biosignatures: A Review of Remotely Detectable Signs of Life
Year: 2017
Type: article
Abstract: In the coming years and decades, advanced space- and ground-based\nobservatories will allow an unprecedented opportunity to probe the atmospheres\nand surfaces of potentially habitable exoplanets for signatures of life. Life\non Earth, through its gaseous products and reflectance and scattering\nproperties, has left its fingerprint on the spectrum of our planet. Aided by\nthe universality of the laws of physics and chemistry, we turn to Earth's\nbiosphere, both in the present and through geologic time, for analog signatures\nthat will aid in the search for life elsewhere. Considering the insights gained\nfrom modern and ancient Earth, and the broader array of hypothetical exoplanet\npossibilities, we have compiled a state-of-the-art overview of our current\nunderstanding of potential exoplanet biosignatures including gaseous, surface,\nand temporal biosignatures. We additionally survey biogenic spectral features\nthat are well-known in the specialist literature but have not yet been robustly\nvetted in the context of exoplanet biosignatures. We briefly review advances in\nassessing biosignature plausibility, including novel methods for determining\nchemical disequilibrium from remotely obtainable data and assessment tools for\ndetermining the minimum biomass required for a given atmospheric signature. We\nfocus particularly on advances made since the seminal review by Des Marais et\nal. (2002). The purpose of this work is not to propose new biosignatures\nstrategies, a goal left to companion papers in this series, but to review the\ncurrent literature, draw meaningful connections between seemingly disparate\nareas, and clear the way for a path forward.
Authors: Schwieterman, Edward W, Kiang, Nancy Y, Parenteau, Mary N, Harman, Chester E, DasSarma, Shiladitya, Fisher, Theresa M, Arney, Giada N, Hartnett, Hilairy E, Reinhard, Christopher T, Olson, Stephanie L, Meadows, Victoria S, Cockell, Charles S, Walker, Sara I, Grenfell, John Lee, Hegde, Siddharth, Rugheimer, Sarah, Hu, Renyu, Lyons, Timothy W
Institutions: University of California, Riverside, Universities Space Research Association, NASA Astrobiology Institute, National Aeronautics and Space Administration, Blue Marble Space Institute of Science, Alternative Earths Astrobiology Center, Goddard Institute for Space Studies, Ames Research Center, Columbia University, University of Maryland, Baltimore, University System of Maryland, Institute of Marine and Environmental Technology, Arizona State University, Goddard Space Flight Center, Georgia Institute of Technology, University of Washington, University of Edinburgh, Santa Fe Institute, Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR), Cornell University, University of St Andrews, California Institute of Technology, Jet Propulsion Laboratory
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W3124069841