Signatures of a shadow biosphere

Paul Davies, Steven A. Benner, Carol E. Cleland, Charles H. Lineweaver, Christopher P. McKay, Felisa Wolfe-Simon

Research output: Contribution to journalArticlepeer-review

80 Scopus citations


Astrobiologists are aware that extraterrestrial life might differ from known life, and considerable thought has been given to possible signatures associated with weird forms of life on other planets. So far, however, very little attention has been paid to the possibility that our own planet might also host communities of weird life. If life arises readily in Earth-like conditions, as many astrobiologists contend, then it may well have formed many times on Earth itself, which raises the question whether one or more shadow biospheres have existed in the past or still exist today. In this paper, we discuss possible signatures of weird life and outline some simple strategies for seeking evidence of a shadow biosphere. Astrobiology 9, 241-249.

Original languageEnglish (US)
Pages (from-to)241-249
Number of pages9
Issue number2
StatePublished - Mar 1 2009


  • Alternative
  • Biogenesis
  • Biomarkers
  • Extremophiles
  • Multiple origins of life
  • Weird life

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Space and Planetary Science


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