I was listening to a programme on the radio about Plate Tectonics yesterday. Two things particularly struck me. The first was how new the science was; for something that explains at a profound level how our planet is formed it seemed amazing to me that the theory has only received widespread acceptance in the last thirty years. How did people think mountain ranges and oceans were formed before? Volcanic activity is a plausible explanation but there was one huge phenomena that defies any other answer than plate tectonics and it is how the Atlantic did not fill up with the vast amount of silt disgorged by the rivers of Africa and America.
The interesting thing about this question is that nobody asked it. The physical facts were there to be wondered at. For many centuries we knew how vast the Amazon and Congo deltas were and the sort of volumes of debris that they produced and had produced for millennia: so where did it all go?
The answer we now know is the process of subduction, where one continental plate slides under the other and in the process takes that silt back into the earth’s core to be, in a sense, recycled. This theory, or fact as it now is, explains why the Atlantic is still there and full of water - so why had no one even asked that question? Perhaps it shows the weakness of the scientific method in that it is all very well ‘standing on the shoulders of giants’, as Newton put it, but even he needed an apple to fall on his head to make the big leap.
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