Dr. van Eyken will describe the past, present, and future of Arecibo Observatorythe world's largest, most sensitive single-dish radio telescope, located in Puerto Rico. Preeminent for its research in astronomy, space studies, and atmospheric science, the facility is a unique resource for the research community. Its legacy includes the first radar-ranging of an earth orbit-crossing asteroid, early maps of several solar system objects, a Nobel Prize for confirming Einstein’s general theory of relativity through the timing of binary pulsar orbital decay, and the first detection of planets orbiting another staramong dozens of its other breathtaking discoveries. The 1,000-foot-wide telescope has even appeared in movies (GoldenEye, Contact) and TV (The X Files). More than 100,000 people visit the facility each year. As it marks its first half-century, the Observatory is expected to continue to amaze the world with its discoveries for generations to come.