While "life" may universally be a self-sustaining chemical system capable of Darwinian evolution, alien life may be quite different in its chemistry from the terran life that we know here on Earth. In this case, it will be difficult to recognize, especially if it has not advanced beyond the single cell life forms that have dominated much of the terran biosphere. This review summarizes what we might infer from general physical and chemical law about how such "weird" life might be structured, what solvents other than water it might inhabit, what genetic molecules it might contain, and what metabolism it might exploit.

Date Published: 7 September 2010
PDF: 12 pages
Proc. SPIE 7819, Instruments, Methods, and Missions for Astrobiology XIII, 781910 (7 September 2010); doi: 10.1117/12.866981

Published in SPIE Proceedings Vol. 7819:
Instruments, Methods, and Missions for Astrobiology XIII
Richard B. Hoover; Gilbert V. Levin; Alexei Yu. Rozanov; Paul C. W. Davies, Editor(s)