Posthuman Blues

Finding Biomarkers in an Alien Atmosphere

Kaltenegger (Harvard-Smithsonian Center for Astrophysics) and Wesley Traub (JPL and CfA) are looking closely at the history of Earth’s atmosphere to understand what happens in the various stages of planetary evolution. The development of life is one of many factors that changed the atmosphere in the past 4.5 billion years. When the day comes that we have spectroscopic data from exoplanets as small as Earth, we’ll be able to study the signatures of the gases there to learn something about conditions on the surface.