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Detectability of life and photosynthesis on exoplanets.

  • Lars Olof Björn
  • George C. Papageorgiou
  • Dainis Dravins
  • Govindjee Govindjee
Publishing year: 2009
Language: English
Pages: 1171-1175
Publication/Series: Current Science
Volume: 96
Issue: 9
Document type: Journal article
Publisher: Current Science, Current Science Association and Indian Academy of Sciences

Abstract english

‘Is there life on exoplanets?’. We refer to exoplanets as planets in other solar systems than our own. This often

asked question can be further refined by asking ‘is there life on exoplanets which is so extensive that it may

impact on its atmosphere, its biosphere and its optical properties?’. And if such a life exists, at astronomical

distances from us, can we detect it with instruments on Earth-based or Earth-orbiting observatories? Will

then, in that case, our advanced knowledge of present-day and early-day photosynthesis on Earth help us

select appropriate biosignatures that may signal its presence? Here we elaborate further on these themes,

based on the most recent literature, and from the point of view of photosynthesis. We also provide our considered

views. Although search for chlorophyll is considered desirable, we conclude that our best bet is to

look for and analyse photosynthesis-related gases, namely O2, CO2 and H2O vapour. We shall keep in mind

that the evolutionary tree of life on our planet has its roots in autotrophy, and of the various forms of autotrophy,

only oxygenic


  • Astronomy, Astrophysics and Cosmology
  • Biological Sciences
  • chlorophyll
  • detectability
  • life
  • photosynthesis
  • spectrum


  • Popular science
  • Photobiology-lup-obsolete
  • ISSN: 0011-3891
Lars Olof Björn
E-mail: lars_olof [dot] bjorn [at] biol [dot] lu [dot] se

Professor emeritus

Molecular Cell Biology

+46 46 222 72 53