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-as of [12 APRIL 2024]–
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-the geoid is the shape that the surface of the oceans would take under the influence of earth’s ‘gravity’ + ‘rotation’ alone, in the absence of other influences such as ‘winds’ + ‘tides’-
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(this surface is extended through the ‘continents’ (such as with very narrow hypothetical ‘canals’))
(all points on a ‘geoid surface’ have the same ‘gravity potential energy’ (the sum of ‘gravitational potential energy’ and ‘centrifugal potential energy’))
(the ‘geoid’ can be defined at any value of ‘gravitational potential’ such as within the earth’s ‘crust’ or far out in ‘space’, not just at ‘sea level’)
(the force of ‘gravity’ acts everywhere perpendicular to the ‘geoid’, meaning that plumb linespoint perpendicular and water levels parallel to the ‘geoid’ if only ‘gravity’ and ‘rotational acceleration’ were at work)
(specifically, the ‘geoid’ is the equipotential surface that would coincide with the mean ocean surface of ‘Earth’ if the oceans and atmosphere were in ‘equilibrium’, at rest relative to the rotating ‘earth’, and extended through the continents (such as with very narrow ‘canals’))
(according to ‘gauss’, who first described it, it is the “mathematical figure of Earth”, a smooth but highly irregular surface whose shape results from the uneven distribution of mass within and on the surface of ‘Earth’)
(it does not correspond to the actual surface of Earth’s crust, but to a surface which can only be known through extensive gravitational measurements and calculations)
(despite being an important concept for almost 200 years in the history of ‘geodesy’ and ‘geophysics’, it has only been defined to high precision since advances in ‘satellite geodesy’ in the late 20th century)
(it is often described as the “true physical figure of the ‘earth'”, in contrast to the idealized geometrical figure of a reference ‘ellipsoid’))
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(the surface of the ‘geoid’ is higher than the reference ‘ellipsoid’ wherever there is a ‘positive gravity anomaly’ (‘mass excess’) and lower than the ‘reference ellipsoid’ wherever there is a ‘negative gravity anomaly’ (‘mass deficit’))
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*👨🔬🕵️♀️🙇♀️*SKETCHES*🙇♂️👩🔬🕵️♂️*
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*🌈✨ *TABLE OF CONTENTS* ✨🌷*
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🔥🔥🔥🔥🔥🔥*we won the war* 🔥🔥🔥🔥🔥🔥