image: Future telescopes (right) will observe atmospheres of distant planets for signs of life. Oxygen/ozone reveal life on Earth (top left). For the early Earth (bottom left), the combination of methane and carbon dioxide would provide an alternative biosignature. This material relates to a paper that appeared in the 24 January 2018, issue of Science Advances, published by AAAS. The paper, by J. Krissansen-Totton at University of Washington in Seattle, Wash., and colleagues was titled, "Disequilibrium biosignatures over Earth history and implications for detecting exoplanet life." view more
Credit: [Credit: J. Krissansen-Totton]