The Day the Universe Changed - James Burke [164]
As has been seen, however, the structure contains within it systems which operate at every level to lead the investigator to the most detailed of analyses, and it is often at that level that anomalies occur which cannot be accommodated without a complete change in the contemporary structure.
One such event is described graphically by one of the researchers involved. At the end of 1966 Walter Pitman was looking at new profiles of the magnetic state of certain areas of the ocean floor, when, as he said,
It hit me like a hammer… in retrospect we were lucky to strike a place where there were no hindrances…. We didn’t get profiles quite that perfect from any other place. There were no irregularities to distract or deceive us…
This was one of the rare moments in the history of knowledge when a structure was about to change. It was all the more exciting because the previous structure had been successfully resistant to alteration for over fifty years as it fended off various attempts to reorder the mechanism by which the continents were thought to have arrived at their present position.
In the last century the belief was that while the surface of the earth was subject to relatively constant vertical movement, after an initial cooling or contracting period the land-masses had remained in the positions in which they now were. So some old sea basins were now mountains, and mountain ranges were now on the sea-bed. In the 1860s, however, certain similarities between three hundred million year-old fossils in the coal beds of Europe and those of North America caused Antonio Snider-Pellegrini to postulate that the continents had originally fitted together in one giant land-mass.
In 1915 a German meteorologist called Alfred Wegener went into more detail. The coastlines of Africa and North and South America looked as if they had once fitted together. There were striking geological similarities in areas that would, in this scenario, once have been contiguous: the Cape Mountains of South Africa and the Sierras of Buenos Aires; three major geological folds that continued from North America to Europe; the huge gneiss plateaux of Brazil and Africa. Many identical fossils dating from before the palaeozoic era (and virtually none from later) were recovered from South America and Africa.
For Wegener these and other questions could only be explained by the fact that the continents had once been joined and had since parted. He described the continents as being like giant icebergs of silicon and aluminium ‘floating’on a sea of heavier basaltic material that formed the ocean floors. They had simply drifted apart.
The proposal was greeted with universal scorn. Wegener was not a geologist. There was no known mechanism which would propel the continents. The softer land-masses could not ‘plough’through the harder ocean floor. The problems he had posed were pseudo-problems. The bio-geographical similarities of the fossils were evidently attributable to the fact that ancient land bridges, now sunk, had once connected the continents, or to seeds and spores being carried on the wind across the sea. In any case, the continents did not fit exactly. The questions Wegener had raised were thus answered satisfactorily within the terms of the contemporary structure, and for thirty years no further serious defence of his view was attempted.
By the 1950s developments in an apparently unrelated field caused a reappraisal. Newly invented magnetometers had shown that the earth had a magnetic field which was parallel to the axis of rotation. Moreover, studies showed that rocks retained their original magnetic orientation, and that over aeons, changes had occurred, either in the position of the magnetic poles or in the position of the rocks as indicated by their residual magnetism. If movement accounted for the present magnetic orientation, India must have migrated north, and England also had moved north while rotating