Explore the intersection of biology, earth sciences, and space exploration in this AGU Fall Meeting 2009 Sagan Lecture. Delve into the fundamental principles of life, from energy requirements to environmental factors, as NASA Ames Research Center's Tori Hoehler presents "Life at the Common Denominator: Mechanistic and Quantitative Biology for the Earth and Space Sciences." Trace the scientific journey from Galileo and Kepler to modern space missions, examining the potential for life beyond Earth. Investigate the discrete minimum requirements for life, energy production in biological systems, and the concept of habitability. Analyze case studies such as methane plumes, serpentinization, and the Lost City hydrothermal field to understand the application of these principles. Gain insights into habitability conceptual models, supply-side considerations, and the relationship between various environmental factors. Conclude with a reflection on the next steps in this interdisciplinary field and its implications for our understanding of life in the universe. Read more