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The language of exoplanet ranking metrics needs to change

Nature Astronomy volume 1, Article number: 0042 (2017) Cite this article

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We have found many Earth-sized worlds but we have no way of determining if their surfaces are Earth-like. This makes it impossible to quantitatively compare habitability, and pretending we can risks damaging the field.

Over 3,000 planets have been confirmed beyond our Solar System, a third of which have radii smaller than twice the radius of Earth1. This swarm of approximately Earth-sized worlds has led to intense speculation about whether such planets might also harbour life. In the next decade, telescopes capable of tackling this question will start to be available. But with thousands of planets and observational hours in high demand, target prioritization is essential. This has led to the development of metrics to rank planets for future habitability studies. Three of the most commonly used metric are described below; all of them attempt to identify the exoplanets most likely to show signs of life.

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Author information

Authors and Affiliations

  1. Elizabeth Tasker is at the Institute of Space and Astronomical Science, Japan Aerospace Exploration Agency, Yoshinodai 3-1-1, Sagamihara, Kanagawa, Japan.,

    Elizabeth Tasker

  2. Joshua Tan is at the Instituto de Astrofísica, Pontificia Universidad Católica de Chile, Av. Vicuna Mackenna 4860, 782-0436 Macul, Santiago, Chile.,

    Joshua Tan

  3. Kevin Heng is at the University of Bern, Center for Space and Habitability, Sidlerstrasse 5, CH-3012, Bern, Switzerland.,

    Kevin Heng

  4. Stephen Kane is in the Department of Physics & Astronomy, San Francisco State University, 1600 Holloway Avenue, San Francisco, California 94132, USA.,

    Stephen Kane

  5. David Spiegel is at Analytics & Algorithms, Stitch Fix, San Francisco, California 94103, USA.,

    David Spiegel

  6. Earth Life Science Institute, Tokyo Institute of Technology, Meguro-ku, 152-8550, Tokyo, Japan

    Ramon Brasser, John Hernlund, Christine Houser, Matthieu Laneuville & Marine Lasbleis

  7. Institute of Astronomy, University of Cambridge, Cambridge, CB3 0HA, UK

    Andrew Casey

  8. School of Earth & Space Exploration, Arizona State University, Tempe, 85287, Arizona, USA

    Steven Desch

  9. Space Research & Planetary Sciences, University of Bern, Sidlerstrasse 5, 3012, Bern, Switzerland

    Caroline Dorn

  10. Department of Mathematics, naXys, University of Namur, 8 Rempart de la Vierge, 5000, Namur, Belgium

    Anne-Sophie Libert

  11. Department of Reference Systems and Planetology, Royal Observatory of Belgium, Avenue Circulaire 3, 1180, Brussels, Belgium

    Lena Noack

  12. School of Earth & Space Exploration, Arizona State University, Tempe, 85287, Arizona, USA

    Cayman Unterborn

  13. Department of Geosciences, Princeton University, Princeton, 08544, New Jersey, USA

    June Wicks

Authors
  1. Elizabeth Tasker
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  2. Joshua Tan
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  3. Kevin Heng
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  4. Stephen Kane
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  5. David Spiegel
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Consortia

the ELSI Origins Network Planetary Diversity Workshop

  • Ramon Brasser
  • , Andrew Casey
  • , Steven Desch
  • , Caroline Dorn
  • , John Hernlund
  • , Christine Houser
  • , Matthieu Laneuville
  • , Marine Lasbleis
  • , Anne-Sophie Libert
  • , Lena Noack
  • , Cayman Unterborn
  •  & June Wicks

Corresponding author

Correspondence to Elizabeth Tasker.

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Tasker, E., Tan, J., Heng, K. et al. The language of exoplanet ranking metrics needs to change. Nat Astron 1, 0042 (2017). https://doi.org/10.1038/s41550-017-0042

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  • DOI: https://doi.org/10.1038/s41550-017-0042

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