Ever the scientist, while cruising from one battle to the next, Hess kept the transport’s sounding gear (which bounced sound waves off the sea-floor in order to determine the underwater relief or topography) running day and night. Cape Johnson in the Pacific Ocean, taking part in major landings at Marianas, Leyte, Lingayen Gulf, and Iwo Jima. He then served as commander of the attack transport U.S. He soon developed a system for estimating the daily positions of German U-boats in the North Atlantic, and requested duty aboard a decoy vessel in order to test the program. Already a lieutenant junior grade in the Naval Reserve, Hess was called to active duty after Pearl Harbor and was eventually to rise to the rank of Rear Admiral. Nevertheless he stuck with it, and was teaching geology at Princeton when World War II was declared.

It was Hess who determined how oceanic mountain ranges, called mid-ocean ridges, are fundamental to the tectonic movement that results in the drift of continents.Īccording to his own account, Hess flunked his first course in mineralogy at Yale and was told he had no future in the field. Wegener’s critics correctly pointed out, however, that the continents could not simply “plow” though the ocean floor as Wegener had vaguely theorized. These lines of evidence included, for example, matching geological formations and paleontological distributions from South America and Africa. This idea was transformed into the theory of “continental drift” by German meteorologist Alfred Wegener in 1912, when he published a treatise with several lines of supporting evidence that went beyond simply matching the continents like puzzle pieces. The idea that the continents might have moved, or “drifted” over time can be traced back to the sixteenth century, when European cartographers compiled world maps based on the seagoing expeditions of that time. This unusual combination produced groundbreaking work on a number of subjects, including the origin of ocean basins and island arcs, mountain building, and the movement of continents. Hess possessed two valuable skills: careful attention to detail and the ability to form sweeping hypotheses. One of them, Harry Hess, was an instrumental figure in figuring out how plate tectonics worked. This process is called plate tectonics, and it transformed the thinking of geologists. Yet the surface of the Earth is not fixed, but rather broken up like a jigsaw puzzle into enormous plates that move. Nothing could feel more solid than the ground under our feet. Photo courtesy of Princeton University, Department of Geosciences.

Harry Hess (1906–1969) in his World War II Naval uniform.

Mid Ocean by T. Rafael Cimino