If the Earth stopped spinning

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    Earth Spinning
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Discussion Overview

The discussion explores the hypothetical scenario of the Earth stopping its rotation, focusing on the implications for gravity, atmospheric conditions, weather patterns, and the effects of inertia on objects at the surface. Participants examine various physical forces at play and their potential consequences.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that the centripetal acceleration due to Earth's spin is negligible, suggesting that individuals would not notice a significant change in their weight or ability to walk if the Earth stopped spinning.
  • Others calculate the centripetal acceleration and note that it is a small fraction of gravitational acceleration, with values varying by latitude.
  • One participant mentions that if the Earth stopped spinning, the oceans would redistribute, potentially leading to two polar oceans and a dry equatorial landmass.
  • Concerns are raised about atmospheric changes, including the possibility of the atmosphere leaking into space and the implications of one side of the planet being in constant sunlight while the other remains in darkness.
  • Some participants discuss the effects of losing centrifugal and Coriolis forces, which could impact weather patterns, although these forces are described as relatively small compared to gravity.
  • There is a claim that if the Earth stopped spinning suddenly, people would experience inertia and potentially collide with stationary objects at high speeds, with varying estimates of the speed depending on latitude.
  • One participant questions the assumption that gravity would weaken, while another clarifies that the force of gravity itself would not change, but the absence of centrifugal force would affect the net force experienced by individuals on the surface.
  • There is a discussion about the magnetic field, with one participant suggesting it would diminish if the Earth's core stopped spinning, while another disagrees, stating that the magnetic field is not directly tied to the Earth's rotation.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the effects of the Earth stopping its rotation, particularly concerning gravity, atmospheric conditions, and the consequences of inertia. The discussion remains unresolved with no consensus reached on several points.

Contextual Notes

Some claims depend on specific assumptions about the nature of forces involved, such as the effects of centrifugal force and the behavior of the atmosphere. The discussion includes varying estimates and interpretations of physical phenomena without definitive conclusions.

cj
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OK,

Newton's Universal Law of Gravitation tells me the magnitude of the force I feel here on the surface of the Earth. I know the direction is towards the center of the Earth.

I know g = G x Mass-of-Earth / r^2.

Neglecting all the other ramifications, if the Earth stopped spinning...

...would I still be able to walk around as before?

...would there be no difference in the gravity I experience (would I "weigh" the same?)?

Is there really no effect I would notice as a result of the absence of the my centripetal acceleration (since I'm no longer spinning around, because the Earth is no longer spinning around)?

What do you think?
 
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There is a small effect, which is usually calculated in a first course in geodesy. It changes the "effective equipotential" surface of the Earth (the "ocean surface") from a sphere into an ellipsoid. But it is a tiny effect.
 
the centripetal acceleration caused by Earth spin is so small that you can not sense any changes if the Earth stopped spin. I have calculated it : a=2.1717e-5. It is opposite to the gravity so it is just 0.00022% of gravity acceleration.
 
haiha said:
the centripetal acceleration caused by Earth spin is so small that you can not sense any changes if the Earth stopped spin. I have calculated it : a=2.1717e-5. It is opposite to the gravity so it is just 0.00022% of gravity acceleration.

The value is considerably larger than that, but still quite a bit smaller than the acceleration due to gravity. The centripetal acceleration varies with latitude. At the equator, the value is [itex]6378*10^3*(2\pi/86400)^2 \text{m/sec} = 0.0337 \text{m/sec}[/itex].

The Earth's oceans would split into two polar oceans separated by a dry equatorial landmass if the Earth somehow stopped spinning but maintained its spheroidal shape. http://www.esri.com/news/arcuser/0703/geoid2of3.html discusses this "what if" scenario.

For a larger view, see
http://www.esri.com/news/arcuser/0703/graphics/geoid7_lg.jpg
 
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This is a good question. If the Earth stopped spinning the winds would go north and south instead of east and west. Also I think the atmosphere would slowly leak away into space as Earth's gravitiy would weaken. And if the Earth stopped spinning one side of the planet would be in total darkness as the other would be in total sunlight which in time would be too hot enough for for anything to live there. The only shelter it would receive is from the moon as it passes by the sun even then that wouldn't help much to the animals alive at the time.
 
Kt_Atis said:
Also I think the atmosphere would slowly leak away into space as Earth's gravitiy would weaken.

:confused: Why would gravity "weaken" ?
 
Force of Gravity would not change.
The net force with which we are attracted towards Earth's centre would increase*, if you are standing anywhere exept the poles(actual poles), a small centrifeugal force would now be absent which throws you out of earth, although very small but this force will now be absent.

centrifeugal force = 0 at poles.

well that's the gist.

*Actually there is no force that attracts us towards Earth's centre, gravitation as a force does not exist...for more info. study "general theory of relativity" by einstein .
 
Aside from the loss of a centrifugal force, we would also lose the coriolis force. (The force due to having the Earth spin out from under you as you move). Of course, this is also quite negligible when compared to gravity but does play an important role in weather patterns.
 
I think if the Earth stopped spinning, the weather would change completely of cource and not because the coriolis force only. The coriolis is nothing compared to the fact that one side was always day and the other was night.
 
  • #10
if the Earth stops spinning... would the magnetic field of it diminishes?
 
  • #11
tim_lou said:
if the Earth stops spinning... would the magnetic field of it diminishes?

No that would only be due to the fact that the Earth's core stop spinning.
 
  • #12
If the Earth stops spinning, we would all fly into our houses and walls at 300 km/h, this would most likely kill everyone.

This is because we have an inertia. If you were to calculate the rate of rotation of the earth, we are actually "moving" at a very high speed while standing still on the surface of the earth. We do not feel it because relative to us, everything is moving at the same speed.

If the Earth were to stop, we would continue traveling at this speed and suddenly things are hurtling towards us at ~300 km/h.
 
  • #13
Yes, though it is much faster than that for most people, more like 1000km/hr (latitude dependent).
 
  • #14
It is true that we would crash into objects fixed to the Earth at high speed. However structures such as houses would not be able to withstand such a sudden acceleration and would be ripped off foundations. Also, it is unlikely that the world would suddenly quit spinning. In the event that it did stop, it would probably slow down gradually instead of intantaneously, therefore frictional forces would be maintained and objects would not suddenly be airborne.
 

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