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Show Poles Moving Earth 20 Feet Swing From North to South And Back Again, Observed. NEW YORK. The United States has a north and south motion that sometimes causes the whole country coun-try to travel as much as 20 feet in one direction or the other In 14 months. Literally, the City of Washington, where this movement has Just been verified by 24 years of observation by the United States Naval observatory, observa-tory, changes its latitude by that much in some of the 14-month periods. pe-riods. The change is a swing from north to south and back again. The cause is a newly established wobble of the earth's poles. The evidence Is reported to the American Astronomical Astro-nomical society by William Marko witz, of the naval observatory. The nature of this evidence suggests sug-gests that the entire sides of the earth are similarly swinging. Circuit in 423 Days. This new polar motion is entirely different from two long-known motions. mo-tions. One of these is the preces-sional preces-sional shift, by which the North pole describes a large circle in the heavens heav-ens every 26,000 years. The other motion is a small circle caused by the moon's pull. In both these motions, the earth swings with the pole. But the new motion is made by the pole itself, within the earth, like a stick, set upright in a tub of water but with its top waving around in a small circle. Actually this motion in the pole, or axis of the earth, is an ellipse. The pole completes one circuit each 422 days. As latitude is measured from the pole, the Washington change can be explained in two ways. One is that the pole is moving within the earth. The other, and more literally exact explanation, is that the sides of the earth sag and rise a little, rhythmically, rhythmic-ally, like the shirt of a fat man might push up or down over his middle. There are various theoretical explanations, ex-planations, all based on certain established es-tablished facts. One concerns the weather mostly. May Get Heavier. Siberia being a huge land mass thrust far to the north can conceivably con-ceivably get heavier with ice during the winter. At the same time there is a high-pressure area over Siberia that is the air above that part of the globe Is heavy. This high-pressure high-pressure area coincides roughly with Siberia's winter. These extra weights might cause one side of the earth to sag a little, temporarily. Presumably, at the same time, opposite areas would be moving in an opposite direction, to compensate. Expansion of the earth, and contractiona con-tractiona phenomenon which has been verified by astronomers-might astronomers-might have some influence in the sagging. One point In Markowitz's report greatly Interested astronomers. This was that the latitude changes only within fixed limits and that Washington always comes back to the same mean latitude. To astronomers that is important evidence that the whole continent is not drifting. One theory of the formation for-mation of the continents is that they were originally a single land mass, and that parts of the mass separated separat-ed and drifted apart to form the present continents. The striking similarity of the shore contours between be-tween the eastern Americas and western Europe and Africa suggested suggest-ed this continental drift theory. |
