Explore the frontiers of space exploration and astrobiology in this captivating Sagan Lecture delivered by Jonathan I Lunine from Cornell University's Department of Astronomy. Delve into the scientific imperative driving our quest to understand the cosmos, from the Viking biological experiments to the groundbreaking Voyager missions. Examine the fascinating potential of ocean worlds like Europa and Titan, and learn about cutting-edge remote sensing techniques and hydrothermal processes. Discover the Europa Program and its significance in our search for extraterrestrial life. Engage with the societal implications of these scientific endeavors and contemplate the possible outcomes of our cosmic investigations. This thought-provoking lecture, presented at the 2017 AGU Fall Meeting, offers a comprehensive overview of our current understanding and future directions in solar system exploration and the search for life beyond Earth.