Cryosol | Soil Monoliths Cryosols (or Gelisols in USDA Soil Taxonomy) have permafrost either within 1 m of the surface or within 2 m if the pedon is strongly cryoturbated in the active layer. Monoliths.soilweb.ca
Among the ancient Greeks, Homer thought the world to be flat. In contrast, Pythagoras postulated that the earth was round. A century later, Aristotle sided with the theory of the roundness of the earth.
We have no idea who was the first to realize it, but the Greek mathematician Eratosthenes used observations of the Sun's angle at noon to calculate the diameter of the Earth-a computation that ONLY would have made sense if he knew the Earth to be round.