Resultado de búsqueda
Hace 19 horas · History Pre-industrial era Elevator design by the German engineer Konrad Kyeser (1405). The earliest known reference to an elevator is in the works of the Roman architect Vitruvius, who reported that Archimedes (c. 287 BC – c. 212 BC) built his first elevator probably in 236 BC. Sources from later periods mention elevators as cabs on a hemp rope, powered by people or animals.
Hace 19 horas · Overview Chronology in five stages Diagram of evolution of the (observable part) of the universe from the Big Bang (left), the CMB-reference afterglow, to the present. For the purposes of this summary, it is convenient to divide the chronology of the universe since it originated, into five parts.It is generally considered meaningless or unclear whether time existed before this chronology:
