Biosignature False Positives

  • Chester E. Harman
  • Shawn Domagal-Goldman
Living reference work entry


In our search for life – whether within the earliest part of Earth’s geologic record, on planets within our solar system such Mars, or especially for extrasolar planets – we must infer the presence of life from its impact on the local or global environment. These “biosignatures,” often identified from the known influence of terrestrial organisms on the Earth’s atmosphere and surface, could be misdiagnosed when we apply them to alien worlds. The so-called false positives may occur when another process or suite of processes masks or mimics a biosignature. Here, we examine several leading biosignatures, then introduce potential false positives for these signals, and finally discuss methods to discriminate between the two using current and future detection technologies. We conclude that it is the astrobiology community’s responsibility to thoroughly exhaust all possibilities before we resort to “life” as an explanation.



The authors would like to acknowledge research support from the “ROCKE-3D team” in the NASA’s Nexus for Exoplanet System Science (NExSS), via solicitation NNH13ZDA017C, from the Habitable Worlds program via solicitation NNH15ZDA001N-HW, and from the NASA Astrobiology Institute’s Virtual Planetary Laboratory via solicitation NNH12ZDA002C. This chapter also benefited from Victoria Meadows’ helpful comments.


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Copyright information

© This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply 2018

Authors and Affiliations

  1. 1.NASA Goddard Institute for Space StudiesNew YorkUSA
  2. 2.Department of Applied Physics and Applied MathematicsColumbia UniversityNew YorkUSA
  3. 3.NASA Astrobiology Institute–Virtual Planetary LaboratorySeattleUSA
  4. 4.Planetary Systems LaboratoryNASA Goddard Space Flight CenterGreenbeltUSA
  5. 5.Sellers Exoplanets Environments CollaborationNASA Goddard Space Flight CenterGreenbeltUSA

Section editors and affiliations

  • Victoria Meadows
    • 1
  • Rory Barnes
    • 2
  1. 1.Astronomy DepartmentUniversity of WashingtonSeattleUSA
  2. 2.Astronomy DepartmentUniversity of WashingtonSeattleUSA

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