The Search for Early Forms of Life in Other Planetary Systems: Future Possibilities Afforded by Spectroscopic Techniques

Abstract

A consideration of the basic chemistry of life as we know it suggests good reasons for expecting carbon compounds and water as fundamental elements in extraterrestrial life. It is then possible to establish criteria for habitable planets in terms of their sizes and distances from their stars. If such planets can be found in other solar systems, and observed separately from their stars, simple spectrophotometry can reveal whether or not their atmospheres contain gases such as oxygen, methane and water vapor in concentrations and/or combinations that would indicate the presence of life.