General Mars
  Implications of Life

  Definition of Life
  Martian Meteorite

Data Analysis
  Thin Section Analysis
  Isotope Analysis
  Gas Chromatograph Mass Spectrometer
  Infrared Spectroscopy
  Alpha-Proton X-Ray Spectrometer
  Detection of Carbon Complexes
  Labeled Release
  Gas Exchange
  Pyrolytic Release
  Stimulus Response Experiments

Scientific Research and Design
Introduction - Implications of Life

The implications of finding life on Mars are enormous. All life, both eukaryotic and eubacteria, descends from one common ancestor: archaebacteria. This evolution can be thought of as the tree of life. Terran life is varied, but there are two common characteristics: life utilizes right-handed amino acids and left-handed sugars. If DNA-based life occurs on Mars, an important question is whether or not it displays these same fundamental characteristcs. If it does, then there are two possibilites. One is that life formed on either Earth or Mars and was transferred to the other through some accident (i.e., the interception by one planet of material ejected from the other during meteor impact). The second is that life arose independently on the two planets but followed identical evolutionary pathways. The latter possibility would have special meaning regarding biological processes: our forn of DNA-based life might be inherently more efficient than any other form. Unfortunately, distinguishing between these two options is impossible.

In contrast, if Martian life featured left-handed amino acids and right-handed sugars, we might reasonably conclude that life may arise in more than one basic way and necessarily pursue different evolutionary trees. Such a finding may lead to new understanding of life processes and would substantially increase the mathematical probability of finding life elsewhere in the universe.

Unfortunately, the kinds of information that fuel such debates require appropriate biological material for DNA testing. Possible sources in the Martian environment include spores, living organisms above or (more likely) below the surface, or dead organisms preserved in amber, salt, or permafrost.

mitCopyright © 2000 Massachusetts Institute of Technology
Comments and questions to Last updated: 10 December, 2000