The Lost Worlds of Planet Earth Ortelius hypothesized the idea that land masses may have been connected in the past, Alfred Wegener who hypothesized the idea of a super-continent Pangaea and continental drift despite the prevailing idea of flooded land-bridges at the time, and Bruce C. Heezen and Marie Tharp who discovered the Mid-Atlantic Ridge that supported the theory of plate tectonics. Tyson describes how the landmasses of the earth lay atop the mantle, which moves due to the motion and heat of the earth's outer and inner core. Tyson moves on to explain the asteroid impact that initiated the Cretaceous–Paleogene extinction event, leaving small mammals
The Glory That Was century. Two of de Camp's friends and colleagues, science fiction writers Robert A. Heinlein and Isaac Asimov, with whom he had worked on military research during World War II, were involved in the book in different ways. It features a laudatory introduction by Heinlein and is dedicated to Asimov, whom de Camp stated "helped to push this one over the hump." Asimov recorded some vivid impressions of the author's research for the book in his own introduction to de Camp's short story collection "The Continent Makers and Other Tales of the Viagens" (1953). Twenty-seventh century Earth is united by a