Explore the intersection of isotope geochemistry and astrobiology in this 1-hour 14-minute Sagan Lecture from the 2010 AGU Fall Meeting. Delve into the study of habitability and potential life on other planets as presented by J. Eiler from Caltech's Geological and Planetary Sciences department. Gain insights into the quest for excellence in planetary science and understand key concepts such as astrobiology and geochemistry. Examine the potential for life on celestial bodies like Europa, Titan, and Mars, focusing on factors like ice presence, temperature, and geological history. Investigate the significance of carbonate minerals and methane in the search for extraterrestrial life. Learn about time-dependent variations, serpent realization, and the importance of isotope fingerprinting in identifying potential sources of methane on various planetary bodies.