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

In summary, the conversation discusses the distribution of gravity on Earth's surface due to its non-perfect spherical shape and the inclusion of water as a contributing factor. The topic also touches on the hypothetical scenario of covering the entire Earth with water and how it would affect the shape of the planet. The conclusion is that Earth's surface can be modeled as a spinning spheroid covered with water for many practical purposes.
  • #1
ovais
270
5
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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  • #2
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
 
  • #3
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
 
  • #4
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
 
  • #5
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!
 

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

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

If the Earth were completely covered by water, it would appear to have a spherical shape. This is because water, like all liquids, naturally conforms to the shape of its container, which in this case would be the Earth's gravitational field.

2. Would there be any variations in the Earth's shape if it were covered by water?

Yes, there would be small variations in the Earth's shape due to the movement of ocean currents and tides. These variations would be mostly imperceptible to the human eye, but they can be measured using specialized equipment.

3. How does the Earth's shape affect ocean currents and tides?

The Earth's shape plays a significant role in determining the patterns and strength of ocean currents and tides. The spherical shape of the Earth and its rotation on its axis create the Coriolis effect, which influences the direction of ocean currents. Additionally, the Earth's gravitational pull creates tides as the water is pulled towards and away from the Moon and Sun.

4. What would happen if the Earth's shape suddenly changed?

If the Earth's shape were to suddenly change, it would have significant effects on the ocean's behavior. For example, if the Earth were to become flat, there would be no Coriolis effect and ocean currents would flow in a straight line. Similarly, if the Earth's shape became more oblate, tides would become more extreme in certain areas.

5. Is the Earth's shape constant or does it change over time?

The Earth's shape is constantly changing, albeit very slowly. The Earth's rotation causes it to bulge at the equator and flatten at the poles, and this bulge and flattening can change slightly over time. Additionally, plate tectonics and other geological processes can also cause slight changes in the Earth's shape over millions of years.

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