, Volume 93, Issue 4, pp 155–172 | Cite as

The prospect of alien life in exotic forms on other worlds

  • Dirk Schulze-MakuchEmail author
  • Louis N. Irwin


The nature of life on Earth provides a singular example of carbon-based, water-borne, photosynthesis-driven biology. Within our understanding of chemistry and the physical laws governing the universe, however, lies the possibility that alien life could be based on different chemistries, solvents, and energy sources from the one example provided by Terran biology. In this paper, we review some of these possibilities. Silanes may be used as functional analogs to carbon molecules in environments very different from Earth; solvents other than water may be compatible for life-supporting processes, especially in cold environments, and a variety of energy sources may be utilized, some of which have no Terran analog. We provide a detailed discussion of two possible habitats for alien life which are generally not considered as such: the lower cloud level of the Venusian atmosphere and Titan’s surface environment.


Liquid Ammonia Osmotic Gradient Green Sulfur Bacterium Biosilica Organic Macromolecule 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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© Springer-Verlag 2006

Authors and Affiliations

  1. 1.Department of GeologyWashington State UniversityPullmanUSA
  2. 2.Department of Biological SciencesUniversity of Texas at El PasoEl PasoUSA

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