DPS 2001 meeting, November 2001
Session 60. Extra-Solar Planets
Oral, Chairs: M. Kuchner, M. McGrath, Saturday, December 1, 2001, 2:30-4:10pm, Regency GH

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[60.10] Astrobiology's Central Dilemma: How can we detect Life if we cannot even Define it?

B.C. Clark (Lockheed Martin Astronautics)

Culling and consolidating from a collection of 102 attributes asserted as properties of Life, and the numerous Definitions of Life which invoke them, a new definition is proposed. Analysis of the pathways to proving that any given entity, from micro-sample to planetary object, harbors one or more lifeforms provides strategies for the observations, experiments and detection approaches. These are necessarily varied because of the relative accessibility/inaccessibility of the samples themselves, for example, from Mars, Europa, the ancient Earth or extra-solar system planets.

A two-tiered Definition of Life has been formulated, involving both Lifeform and Organism. Devising exploration strategies with a reasonable probability of success and acceptance should proceed along the steps needed for detection and verification of the minimal properties which define Life itself. Multiple approaches, such as high resolution remote spectroscopy for detection of biomarker gases, in situ demonstrations of energy utilization to performs functions such as anabolic or catabolic transformations, achievement of demonstrated reproduction through multi-condition incubations, and probes for macromolecular biochemicals which indicate information storage should be undertaken wherever possible, as should return of samples to terrestrial laboratories for more versatile, more sensitive and more definitive examinations. Use of control samples is paramount, as is detailed understanding of the chemistry and physics of the environment which constrains the activities and tracers being sought.

The author(s) of this abstract have provided an email address for comments about the abstract: benton.c.clark@LMCO.com

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