Friday , March 06, 2009
By Andrea Thompson
If Friday’s launch goes according to plan and successfully lobs NASA’s new Kepler space telescope into orbit, the mission stands to potentially change the way we look at the universe.
Kepler is designed to turn its eye on thousands of stars in our own Milky Way galaxy and look for signs of Earth-sized planets orbiting in a region conducive to supporting life.
I wonder if they have dumped the following idea…
The Limits of Organic Life in Planetary Systems
Reflecting the near inevitability of human missions to Mars and other locales in the solar system where life might exist, and given the interest of the public in the question, Are we alone?, the National Aeronautics and Space Administration (NASA) commissioned the National Research Council, which formed the Committee on the Limits of Organic Life in Planetary Systems, to address the following questions:
What can be authoritatively said today about limits of life in the cosmos?
What Earth-based research must be done to explore those limits so that NASA missions would be able to recognize, conserve, and study alien life that is encountered?
Theory, data, and experiments suggest that life requires (in decreasing order of certainty):
A thermodynamic disequilibrium;
An environment capable of maintaining covalent bonds, especially between carbon, hydrogen, and other atoms;
A liquid environment; and
A molecular system that can support Darwinian evolution.
Earth abundantly displays life that uses solar, geothermal, and chemical energy to maintain thermodynamic disequilibria, covalent bonds between carbon, water as the liquid, and DNA as a molecular system to support Darwinian evolution. Life with those characteristics can be found wherever water and energy are available.
The natural tendency toward terracentricitya requires that we make a conscious effort to broaden our ideas of where life is possible and what forms it might take. The long history of terran chemistry tempts us to become fixated on carbon because terran life is based on carbon. But basic principles of chemistry warn us against terracentricity. It is easy to conceive of chemical reactions that might support life involving noncarbon compounds, occurring in solvents other than water, or involving oxidation-reduction reactions without dioxygen.