7-Expansion History
EARTH EXPANSION: ITS HISTORY
Expansion of the Earth is an idea that has been around since at least 1888, and possibly earlier. A Russian scientist, I. O. Yarkovskii, is now credited with the first treatise suggesting expansion of the Earth, but Carey appears to have been the first to put together a comprehensive synthesis of geological evidence to support the hypothesis.
Prompted by Alfred Wegener's hypothesis of continental drift, Otto Hilgenberg [1933] was one of the first to recognize that Wegener's drifting continents were the result of expansion of the Earth. To illustrate this he constructed a smaller-Earth terrella (globe) that removed all the oceans and reassembled the continents to form a smaller globe consisting of Wegener’s Pangaea without a Panthalassan ocean. (This is exactly what the current evidence confirms.)
Hilgenberg then constructed successively-larger globes that reintroduced the oceans to show how the planet might have expanded to bring Earth to its present size, but Hilgenberg was unable to provide a mechanism for the expansion.
Professor Carey was another investigator who recognized that Wegener's ideas indicated an expanding Earth. He included this idea in his doctoral dissertation at the University of Sydney in 1938, but removed it at the last minute after realizing it would cost him his doctorate. The literature probably contains evidence of many other geologists who drew the same conclusion from Wegener's work.
Klaus Vogel [1983] presented several different globes showing an expanding Earth at 60% of present diameter in the Archaean before expansion began, and 72% diameter in the Mesozoic after the continents had begun to separate and early ocean basins emerged. Vogel named others who also devised similar small Earth models: Brösske [1962], Barnett [1962], Creer [1965], and Shields [1969].
However, Wegener's concept of drifting continents was not given credence until further discoveries were made in marine geology and geophysics, particularly the 1963 discovery by Vines and Matthew of the midocean ridge system's parallel growth patterns that proved the ridges to be extruding magma and spreading to either side of the central volcanic rift. The ridges then became known as "spreading ridges" and were recognized as the mechanism of continental drift.
It took 50 years for scientists to recognize that Wegener's ideas contained some basic truths, and these now form part of the current philosophy of plate tectonics. Wegener was an original thinker far ahead of his time, with a broad knowledge of the planet that reached far beyond his field of meteorology. For example, in the second chapter of his 1928 book "The Origin of Continents and Oceans," Wegener may have hinted at an earlier connection of Australia and South America with these words:
"The present-day cordilleran system of eastern Australia was formed in still earlier times; it arose at the same time as the earlier folds in South and North America, which formed the basis of the Andes (pre- cordilleras), at the leading edge of the continental blocks, then drifting as a whole before dividing."
Wegener also said (in different context on the next page):
"The outermost layer, represented by the continental blocks, does not cover the whole earth's surface, or it may be truer to say that it no longer does so."
The latter quotation suggests that Wegener may have suspected the Pacific rim continents had been joined together much earlier with Pangaea as a complete outer shell of the planet, but this is unclear. Whatever Wegener had in mind, a Pangaea with the Americas joined to Asia and Australia, while still joined to Europe and Africa, is impossible unless the Earth was then much smaller than its present diameter. There is no evidence that Wegener ever seriously suspected a smaller-diameter Earth because he, too, bowed to the nebular hypothesis when he placed his Panthalassa, the eo-Pacific Ocean that covered most of the planet, on a planet of today's diameter.
Professor Carey was an early supporter of Wegener's drift hypothesis. With his encyclopaedic knowledge of geological and morphological features of the continents and oceans, Carey correctly perceived that the breakup of Pangaea must have been due to expansion of the planet. With this perception, Carey was the first to formulate a detailed concept of "Earth Expansion," which he introduced in 1956 when, as editor, he included a lengthy paper in the Proceedings of a Symposium on Continental Drift he had convened at the University of Tasmania.
Carey expanded on his hypothesis in a subsequent book "The Expanding Earth" [1976] but frankly admitted he could not explain the mechanism driving the expansion and challenged physicists to explain the cause of the expansion he had documented.
Unfortunately, Carey's prescient and insightful hypothesis failed to gain acceptance because of this lack of a plausible causative mechanism--the same critical defect suffered by Wegener's drifting continents for so many years.
Note
This is part 8 of a series of articles written by Lawrence S. Myers in the late 1990s on the Expanding Earth theory. Click "next" to read the subsequent article.
