What is it about?
Tides represent the regular cycles of high and low water in ocean and at coast. Most of people who reached seaside must be shocked by the ebb and flow of the sea. From ancient times, explaining the physics behind this movement of water has tested human wisdom. Historically, a lot of people including Aristotle, Seleucus, Descartes, Kepler, and Galileo had attempted to account for tides. Newton concluded that it is the Moon's (Sun's) gravitational force to raise the sea water, forming tides. Newton's idea was further developed by Pierre-Simon Laplace, William Thomson, Baron Kelvin, Henri Poincare, and Arthur Thomas Doodson, and finally reaches its present form. Current theory explains tides as a manifestation of the response of ocean to the Moon’s (Sun’s) gravitational force. In this study, we present a new theory, in which tides are explained as a manifestation of oscillating ocean basin. In details, solid Earth is mechanically elongated by a combination of the centrifugal force and the Moon’s gravitational force. The elongated solid Earth is spatially represented with a pair of solid bulges that are along the Earth-Moon line. As the Earth spins, this motion entrains the double bulge to regularly raise and put down each part of ocean floor. As a result, the water in ocean basin moves back and forth, forming global water level variation (tides).
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Why is it important?
The new theory represents a significant breakthrough in understanding the physics of tides.
Perspectives
Many people (including tide researchers) said that the current theory is proven to be correct by means of harmonic prediction. In doing so, they apply the tidal force to a specific location and decompose this force into many cosines of amplitude and phase (called tidal constituents), they use each of these constituents to produce a water level variation for the location, and then, the final water level variation at the location is treated as a sum of the water level variations produced by all these tidal constituents. However, this method is not physical. Imagine it, for a beach that is flooded by tides, it becomes entirely exposed after the flood is retreated. And now, please apply the tidal force to the exposed beach, can the force produce a flood of tides? The answer is certainly not. Ocean water (as a fluid) is continuous, any location within it will not simply respond to any force that applies to it, and the water level variation at the location must be a consequence of the water level variations at all oceanic locations. So far, as I see, they argued only that the Moon’s (Sun’s) gravitational force attracts ocean, but they couldn't provide a substantial evidence for the effect of that attraction. Instead, I find that the current theory isn't consistent with the observed tide dynamics at the northern Pacific and Atlantic oceans.
Dr Yongfeng Yang
Bureau of Water Resources of Shandong Province
Read the Original
This page is a summary of: An oceanic basin oscillation-driving mechanism for tides, Physics of Fluids, January 2025, American Institute of Physics,
DOI: 10.1063/5.0250036.
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