Chairs: Stephanie Olson (stephanieolson@purdue.edu) and Avi Mandell (avi.mandell@nasa.gov)

Future NASA flagship space telescopes will have a primary strategic goal of evaluating Earth-like planets for signs of life – specific spectral signatures of biology (biosignatures). However, biosignatures must be interpreted in the context of their broader environment. Although there is a large community focused on various aspects of this complex problem, deeply interdisciplinary synthesis of all of the planetary, stellar, geochemical, and biological phenomena that interact to yield remotely detectable evidence of life (or its absence) remains difficult. The challenges are not only scientific – but also structural, due to the different cultures and historical research focus areas within each discipline. Therefore the time has come to assemble a multi-disciplinary Science Working Group focused on mitigating these challenges and advancing an integrated strategy for exoplanet life detection that will enhance confidence that a planet is truly inhabited, or truly uninhabited.

Our current understanding of the potential biological systems on exoplanets is at a nascent stage, but we hope that the SWG can begin to develop a path towards a more quantitative assessment of inhabitation status. The path forward necessarily includes evaluation of the current planetary atmosphere and surface conditions on target planets based on remotely observable information, but also requires consideration of the viability of biological processes that may yield biosignatures. Moreover, assigning meaning to a non-detection of putative biosignatures requires an understanding of the oceanographic, geochemical, and photochemical phenomena that may limit its accumulation up to abundances detectable with feasible instrumentation and exposure times, yielding a “false negative.” These efforts must also include a focused consideration of all the possible “false positive” scenarios, their observational discriminants, and how these potential ambiguities impact our confidence in any detection of life.

It is especially important that we include the broader exoplanet and astrobiology communities–inclusive of microbiologists, oceanographers, climate scientists, geochemists, atmospheric scientists, and astrophysicists among others–in our search for exoplanet life. No framework for the assessment of the detection of an inhabited planet can be considered valid and rigorous without broad community input and support. The multi-disciplinary exoplanet and astrobiology communities continue to make rapid progress on focused research, but integrating insights from each discipline requires consideration of very different types of data, ranging from qualitative to statistical, and remains a major challenge. NExSS is uniquely well positioned to provide a hub and conduit for such an integrative effort.

The Life Detection Science Working Group focuses on the following goals:

  • Engaging with a broad swath of the remote-life-detection community, with particular attention towards fostering diversity and inclusivity
  • Establishing efficient channels of communication among members of disparate subdisciplines working on life detection problems that are inherently interdisciplinary (a Slack channel, mailing list and Google Drive resources, etc.)
  • Organizing regular virtual workshops/seminars and proposing sessions at major conferences within multiple subfields that will be focused on integrating interdisciplinary knowledge of the factors that impact long-term planetary habitability and biospheric detectability
  • Reviewing and examining overlaps of the previous efforts at systematizing exoplanet life detection, and creating an initial strategy for a community-driven and continually evolving framework for evaluating future observations of exoplanet biosignatures and assigning a life detection confidence level