TIDE IN EARTH’S CRUST IS BELIEVED CAUSE OF LATITUDE VARIATIONS

Manawatu Times, Volume LIV, Issue 6814, 18 January 1929, Page 10

TIDE IN EARTH’S CRUST IS BELIEVED CAUSE OF LATITUDE VARIATIONS

Research Into Moon’s Effects Leads To Conclusions By Astronomer. Possible existence of a constant tide in the earth’s crust caused by the moon, similar on a smaller scale to the sea’s lunar-activated tides, is a theory advanced by Dr. Harlan T. Stetson, assistant professor of astronomy at Harvard University, os the result of nine months of research into the moon’s effects.

The research started, Dr. Stetson said, in seeking a reason why the latitude of a definite point on the globe, measured from the equator, should vary widely when taken at different times. It is now established beyond reasonable doubt, Dr. Stetson asserts, that this variation is caused by the moon.

The exact means by which the moon causes this variation is as yet uncertain, Dr. Stetson states. The existence of an earth tide is one possibility. Another theory is that of a moon-caused tide in the earth’s atmosphere, which would seemingly chango the position of the stars from which measurement is made. Shift in Axis of Dotation. Still another concerns a shift in the earth’s instantaneous axis of rotation, automatically shifting the earth’s equator. Perhaps, Dr. Stetson summed up, the variation is caused by a combination of al lthree rather than any one alone, as all have enough basis of feet to warrant mention.

“Few people realise,” Dr. Stetson said, “that by measuring from the stars, a point 1000 miles away from the equator may be found within a foot of accuracy. By looking at the stars I could tell which side of the room I was on.”

“For many years it has been known that if the position of Boston, for instance, was taken in the morning and again at night, the two figures would Dot bo the same. Why? No one has known, except that there is a small seasonal variation, probably caused by added ice and snow on one side of the globe.” Systematic Daily Proposition.

Working in the Harvard Astronomical Laboratory on .Tarvis Street, Cambridge, with the assistance of Miss Margaret Olmstead, a graduate student at Radeliffc, Dr. Stetson calculated through thousands of United States naval observatory latitude observations, taking into account the moon 's position in each. Finally came the confirmation that thischange in latitude is not only a daily proposition but a systematic one. Dr. Stetson exhibited a plotted line showing this diurnal rise and fall of latitudo directly dependent upon the moon's rising and setting. Although involving much not-easily-understood technical explanations, it was indicated that the final results may bring radical changes into the fields of geology and geophysics as W'cll as astronomy.

While reluctant to comment upon the situation until further research is made, Dr. Stetson said that it might be possible to link up the chronological occurrence of earthquakes with this discovery. If lunar., action actually docs cause ti tide in the earth's crust, he said, study may chow that earth disturbances occur most frequently when the earth’s surface is stretched to its fullest point, or its high tide. Establishment, of this fact, he concluded, might well cause a rearrangement of geological theory.