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Swansong Biospheres: The biosignatures of inhabited earth-like planets nearing the end of their habitable lifetimes

Published online by Cambridge University Press:  06 January 2014

Jack T. O'Malley-James ,
Jane S. Greaves ,
John A. Raven  and
Charles S. Cockell
Jack T. O'Malley-James
Affiliation:
School of Physics & Astronomy, University of St Andrews, St Andrews, UK email: [email protected]
Jane S. Greaves
Affiliation:
School of Physics & Astronomy, University of St Andrews, St Andrews, UK email: [email protected]
John A. Raven
Affiliation:
Division of Plant Sciences, University of Dundee at TJHI, The James Hutton Institute, Invergowrie, Dundee, UK email: [email protected]
Charles S. Cockell
Affiliation:
UK Centre for Astrobiology, School of Physics & Astronomy, University of Edinburgh, Edinburgh, UK email: [email protected]
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Abstract

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The biosignatures of life on Earth are not fixed, but change with time as environmental conditions change and life living within those environments adapts to the new conditions. A latitude-based climate model, incorporating orbital parameter variations, was used to simulate conditions on the far-future Earth as the Sun enters the late main sequence. Over time, conditions increasingly favour a unicellular microbial biosphere, which can persist for a maximum of 2.8 Gyr from present. The biosignature changes associated with the likely biosphere changes are evaluated using a biosphere-atmosphere gas exchange model and their detectability is discussed. As future Earth-like exoplanet discoveries could be habitable planets nearing the end of their habitable lifetimes, this helps inform the search for the signatures of life beyond Earth

Keywords

AstrobiologySun: evolutionEarth
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 8 , Symposium S299: Exploring the Formation and Evolution of Planetary Systems , June 2013 , pp. 378 - 379
Copyright
Copyright © International Astronomical Union 2013 

References

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O'Malley-James, J. T., Greaves, J. A., Raven, J. A., & Cockell, C. S.: Swansong Biospheres: refuges for life and novel microbial biospheres on terrestrial planets near the end of their habitable lifetimes, Int. J. Astrobiology, Vol. 12, pp. 99–112, 2013a.CrossRefGoogle Scholar