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Ancient egyptian plumb bob5/27/2023 Undoubtedly, we have lost so much information with the fall of these Wonders. Without proof of the existence of the Hanging Gardens of Babylon, the Great Pyramid of Giza is the last Wonder standing, The Temple of Artemis was destroyed for the final time back in 401 AD the Statue of Zeus at Olympia was taken by fire the Colossus of Rhodes, the Mausoleum at Halicarnassus, and the Lighthouse of Alexandria were all levelled by earthquakes. I was hoping that some principle (I can't do the math) would explain that the center of gravity, as a point in space, alone controls the plumb bob.Of the Seven Wonders of the Ancient World, only one remains to this day. I appreciate your explanation which I think fits with what the authors of the textbook were saying, but to me it is counter intuitive to think that there could be such thing as a "local" deviation from vertical at all, when the the mountains are part of the net-mass center of gravity to begin with. I gather from your question that in the neighbourhood of the Himalaya the local direction of gravity (hence the local vertical) is significantly deviated from being perpendicular to the reference ellipsoid." That allows you to process surveying data: It will allow you to figure out which parts of the inland are above or below sea level. ![]() On such a perfect planet the direction of the local vertical is perfectly predictable: perpendicular to the reference ellipsoid. "That procedure is perfectly reliable on a planet that is a perfect reference ellipsoid (with perfectly uniform density). I gather from your question that in the neighbourhood of the Himalaya the local direction of gravity (hence the local vertical) is significantly deviated from being perpendicular to the reference ellipsoid. That procedure is perfectly reliable on a planet that is a perfect reference ellipsoid (with perfectly uniform density). So at every data point they need to establish the local vertical, and then you measure the angle between that local vertical and the line to the next data point. Then they work in inland direction, working out everywhere (from the measurments) whether the next data point is at a higher altitude than the previous one, or lower, or equal. I'm assuming for now that the surveyors work out altitude data as follows: they start in a coastal area, referencing local altitude to sea level. ![]() I'm assuming for now that among the data collected by the surveyors was altitude data. I do understand the "outside" influences, like the changing position of the moon, could compromise the pb's results, but not features of the body itself, which are part of the net mass. by Tarbuck and Lutgens, 2002, p.560) that "during the first survey of India, an error in measurement occurred because the plumb bob on an instrument was deflected by the massive Himalayas." There is more detail on this, but this statement on deflection is allowed to stand.Īm I crazy, because this just seems wrong to me? I understand that a plumb bob always points to the Earth's or any body's center of gravity, no matter the shape or lack of uniformity in density of the body or where the plumb bob is situated. ![]() I was reading in my geology book (Earth: An Introduction To Physical Geography, 7th ed.
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