Jeannette Eileen Jones discusses the idea of Africa in the American imagination from the "Darkest Africa" of Henry Morton Stanley to the "Bright Africa" of naturalists, artists, and intellectuals. She is the author of In Search of Brightest Africa, Reimagining the Dark Continent in American Culture, 1884-1936.

Scientists have now identified almost 4000 exoplanets --planets that orbit stars outside our own solar system-- and with powerful new telescopes about to come on line, that number is about to skyrocket. Exoplanet scientist Hannah Wakeford, Giaconni Fellow at the Space Telescope Science Institute, discusses this revolutionary new field and its impact on Earth and planetary sciences.

Cannibals, headless men, and giants were common figures of Medieval and Renaissance maps. Historian Surekha Davies tells us why we need to take these figures seriously. Davies is the author of Renaissance Ethnography and the Invention of the Human: New Worlds, Maps and Monsters (Cambridge University Press, 2016)

David Munns, professor of history at John Jay College, talks about his new book, Engineering the Environment: Phytotrons and the Quest for Climate Control in the Cold War, but we also talk about Matt Damon, shitting in space, and growing pot in your dorm room.

In 1946, Swedish and Finnish observers reported "ghost rockets" flying over Scandinavia. In the United States, they became known as "flying saucers." Historian Greg Eghigian discusses the science and culture of UFOs in the twentieth century.