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Originally Posted by kilopi
I think ExpErdMann admitted in a previous thread that the preponderance of modern data does not support expansion in the current time, so any tests would have to be from existing historical data.
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I don't think I said that! We do have ongoing seafloor spreading at midocean ridges. Without subduction we must suppose the Earth to be expanding. To prove that the Earth is actually expanding is however a difficult task. There are GPS studies showing that certain parts of the globe are rising. I suppose if such rising occurred everywhere on the globe that might constitute proof of expansion. But here again, expansion could be episodic, in which case the absence of positive results now do not mean that expansion never happened or that it will not happen again.
I did concede that experiments to measure decreasing G according to Dirac's theory have mostly negative results. In the previous thread I perhaps focused too much on the decreasing G theory. I don't know of too many expansionists who are supporting that mechanism.
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As to ExpErdMann's five points in the OP, most of them have been dealt with. For instance, point 1) says "Such perfect matching of continents is unlikely to have arisen by chance." There is absolutely no way of determining that likelyhood, and I've mentioned before that a lot of math models would place the probability quite high. Also, you'd have to ignore an awful lot of geophysical data to say, as in point 2), "There is no 'smoking gun' of subduction."
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On point 1 we disagree of course. Point 1 is EE's smoking gun. One of the pieces of evidence which ushered in plate tectonics was Carey's fitting together of South America and Africa by including the shelves. This was considered proof positive of continental drift. So when you say that the far more dramatic demonstration by Hilgenberg, Carey and others that all the continents fit together perfectly on a smaller globe, you are going to some different standard of evidence, one which eludes me. On point 2 there is a lot of conjecture surrounding subduction, but I submit there is no smoking gun.
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In point 3), he said " one would expect to find here and there relics of older sea floors billions of years old. These have not been found." Someone mentioned in the previous thread that these have been found, so that point is easily dismissed.
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DStahl said on page 4 of the previous thread that there were surface rocks in Oregon that were derived from seafloor, stating this was evidence that seafloor could escape subduction. He didn't gave the ages of these rocks however. If they were older than 300 million yeears that would be interesting.
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Point 4), that "Fossil evidence supports this general trend" of water receding over all of geologic time, is just not true. The water has ebbed and flowed many times.
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Ice ages have of course caused temporary fluctuations. I am referring to a longterm transition from submerged continents to exposed ones. No one has provided feedback on this yet.
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Point 5) surprises me, as I don't remember hearing it before: "The expanding earth theory explains why the continents are very even in thickness. Plate tectonics has no explanation for this." Probably the reason plate tectonics doesn't explain it is because it isn't true. The continental plates vary considerably in thickness.
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They vary by a few kilometers are so from place to place, but this is small potatoes. EE explains the even thickness nicely, since the sial crust differentiated out smoothly over the whole globe as it cooled. In PT, you need to explain why the sial crust differentiated to cover only 1/4 of the globe and why it did this at even thickness.
Expansion on Earth could occur in phases, as you say, and this makes it a hard thing to study. Since it is difficult to measure changes in the Earth's size in any case, I would be happy to limit this discussion to the question: Did expansion occur on Earth and Mars in the past? This is the most interesting question from the evolutionary perspective.
As for Tuzo Wilson, I think he saw which way the parade was going and opted to be a leader rather than to be ignored on the sidelines!