Abstract: Many of the features that are thought of as biosignatures – including the mediation of chemical and physical processes with speed, specificity, and selectivity – result directly or indirectly from life’s unique capability to mediate and direct energy flux. As such, it is important to consider the impact that differences in energy flux may have on the quantity and quality of evidence for life. Earth differs from every other body in our solar system in the magnitude of biologically-usable energ…