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Submarines, theCold War, and advances in Geophysics

Submarines proved its worth during WWII. But a crucial defect of a submarine is its inability to stay underwater for more than a couple of hours since its battery will be drained and must re-surface to recharge its batteries using regular oil-burning and oxygen consuming engines. But this problem disappeared when nuclear powered submarine was developed after the war. Submarines can stay underwater days at a time since nuclear reactors do not need  oxygen . But another problem reared it head.How does a submarine know its location under the sea without radio communication or other direction finding devices (remember  this is decades before GPS)? The solution is to completely mapped the ocean floor just as we develop maps of our dry land so that we will know ocean landmarks and use them to navigate just as we travel on land. Thus US started a ultra secret plan in the early ‘60s to do just that. The famed dive to the bottom of the Marianna trench near the Philippines in 1960 was one of the very few events that the public were allowed to know.  One of thehappy by-products of this secret military  effort  was numerous discoveries of geophysics as a result.   The best known example is the discovery and development of the science of Plate Tectonics. .Another interesting discovery is the fact that the earth magnetic poles reverse direction every some 300,000 years. The evidence of this was the magnetic records of the lava material pushed out from the middle of  Atlantic ocean trenches.  Auxiliary discoveries of undersea volcanoes, earthquake, and other phenomena  greatly increased our knowledge of the geophysical sciences – the serendipitous ways of scientific advances.