As NASA’s Europa Clipper spacecraft leaves Earth, it carries a message: we, too, are made of water. Europa—one of Jupiter’s moons—is a top candidate to support life, thanks to its ocean of liquid, salty water capped by a layer of ice. Lynnae Quick-Henderson, a planetary scientist at NASA, explains how Clipper will search Europa for the building blocks of life. The mission is also a message in a bottle, bringing a greeting from one ocean world to another. Hear how Ada Limón, the Poet Laureate of the United States, used NASA’s mission as inspiration for her poem “In Praise of Mystery: A Poem for Europa” and why she thinks everyone—even space nerds—should step back and appreciate our connections to the universe and each other.