What shape would the Earth appear to have if it were just covered by water

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Discussion Overview

The discussion revolves around the shape that the Earth would appear to have if it were completely covered by water, considering the effects of gravity variations due to the Earth's non-uniform shape. Participants explore the implications of Earth's gravitational field and the distribution of water across its surface.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant suggests that the varying gravity due to Earth's non-spherical shape complicates the understanding of how water would distribute across the surface.
  • Another participant notes that while water contributes to the overall gravity of Earth, its density is low compared to rock, implying limited impact on gravitational variations.
  • There is a question about whether the shape of the Earth, when covered by water, would resemble its current solid surface or take on a different form, such as a perfect sphere.
  • A participant references the concept of the geoid as a potential model for understanding the shape of the Earth covered by water.
  • It is mentioned that the free fall acceleration varies from the equator to the poles, with some of this variation attributed to Earth's rotation and shape.
  • A participant proposes that modeling Earth as a spinning spheroid covered with water is a reasonable approximation for certain analyses.

Areas of Agreement / Disagreement

Participants express differing views on the implications of water's density and the resulting shape of the Earth when covered by water. There is no consensus on the exact shape or distribution of water, and the discussion remains unresolved.

Contextual Notes

Participants acknowledge the neglect of Earth's rotation and revolution around the sun in their considerations, which may affect the analysis of water distribution and gravitational effects.

Ahsan Khan
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Hello all,

I was going through study of gravitation of earth. The book teachs that gravity of Earth is more near poles than at equator as Earth is not perfect sphere rather radius of Earth is lesser near poles larger at equator. A thought came in my mind that if the water at level goes also through a varying gravity due to non-unformity of Earth spherical shape, I am also thinking that water itself is a contributing thing for overall gravity of Earth afterall water is also part of earth. And this whole complex system makes me not to figure out the real distribution of gravity at different points on earth' surface(including the surface covered by water). Will appreciate if anybody through light on this issue also I would like to know if I could take enough water so that if uniformly placed on Earth surface it could cover whole Earth If Earth were sphere. Keeping the fact that Earth is not perfect sphere and gravity is not uniform everywhere how would my water would spread on earth. Neglect effect of Earth's rotation and revolution around sun.

Regards
 
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ovais said:
I am also thinking that water itself is a contributing thing for overall gravity of Earth afterall water is also part of earth

yeah, but not much ... water density compared to rock is low
ovais said:
Will appreciate if anybody through light on this issue also I would like to know if I could take enough water so that if uniformly placed on Earth surface it could cover whole Earth If Earth were sphere

of course
and if the density was uniform through this spherical earth, then the depth of the water would also be uniform,
on a non-rotating/non-orbiting a sun and no moon, earth
 
So how would then it shape appear, same as that of solid surface seen now or a perfect sphere or what can be predicted about a modified shape?

Regards
 
ovais said:
So how would then it shape appear, same as that of solid surface seen now or a perfect sphere or what can be predicted about a modified shape?
Do you mean this?
https://en.wikipedia.org/wiki/Geoid
 
The free fall acceleration at sea level on Earth's surface varies from about 9.78 m/s2 at the equator to 9.83 m/s2 at the poles. About 2/3 of this difference is due to Earth's rotation, the remaining 1/3 due to the fact that Earth's radius is larger at the equator than at the poles.

Earth's surface is mostly covered with water, so modelling it as a spinning spheroid completely covered with water is a reasonable approximation for many purposes!
 

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