Former NASA astronaut and planetary scientist Tom Jones and Alan Boyle preview Asteroid Day, an occasion that highlights the threats and opportunities posed by near-Earth objects. Scores of Asteroid Day events are scheduled around the world on Tuesday,  which marks the 107th anniversary of the 1908 Tunguska asteroid explosion. Jones is the chairman of the Committee on Near-Earth Objects of the Association of Space Explorers, a supporter of Asteroid Day and signerr of the 100X Declaration.