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 Songs of Distant Earth with Earth due to the destruction of its communication abilities by a volcanic eruption 400 years after its founding. The giant radio dish is never repaired due to an ingrained tendency to procrastinate, a trait common among the Thalassans. The Thalassans are therefore unaware of later developments on Earth, including manned interstellar travel. The Earth assumes the destruction of the colony as well. Two hundred and fifty years after the end of Earth the "Magellan" arrives at Thalassa, the midpoint of a 550-year voyage to colonise the distant ice planet Sagan 2. Primarily the objective is to replenish the ship's