# If the Earth stopped spinning

• cj
In summary, the Earth's Universal Law of Gravitation determines the magnitude and direction of the force we feel on the surface, and this can be calculated using g = G x Mass-of-Earth / r^2. If the Earth were to stop spinning, there would be a small effect on the "effective equipotential" surface of the Earth, causing the ocean to split into two polar oceans. The atmosphere would slowly leak away into space, and one side of the planet would be in total darkness while the other would be in total sunlight. The coriolis and centrifugal forces would also be lost, leading to significant changes in weather patterns. However, the magnetic field of the Earth would not diminish unless the core stopped spinning as
cj
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?

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 $6378*10^3*(2\pi/86400)^2 \text{m/sec} = 0.0337 \text{m/sec}$.

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

Last edited by a moderator:
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.

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.

if the Earth stops spinning... would the magnetic field of it diminishes?

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.

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.

Yes, though it is much faster than that for most people, more like 1000km/hr (latitude dependent).

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.

## 1. What would happen if the Earth stopped spinning?

If the Earth stopped spinning, the atmosphere and oceans would still be in motion with the Earth's original 1100 mile per hour rotation speed. This means that hurricanes, tornadoes, and other weather systems would cease to exist. The Earth would also experience extreme temperature differences between the day and night sides of the planet.

## 2. Can the Earth actually stop spinning?

Technically, yes, the Earth could stop spinning due to external forces such as a massive asteroid impact or a collision with another planet. However, the Earth's angular momentum makes it highly unlikely that it would stop spinning on its own.

## 3. How would stopping the Earth's rotation affect gravity?

The Earth's rotation has a minimal impact on its overall gravity. Stopping the rotation would not significantly change the Earth's gravitational pull on objects. However, the lack of centrifugal force from the Earth's rotation could cause a slight increase in weight for objects at the equator.

## 4. Would the Earth's rotation stopping affect our daily lives?

Yes, if the Earth were to suddenly stop spinning, it would have catastrophic effects on our daily lives. The sudden stop would cause massive earthquakes, tsunamis, and volcanic activity. The loss of the Earth's magnetic field, which is generated by its rotation, would also expose us to harmful solar radiation.

## 5. Is there any way to stop the Earth's rotation?

As mentioned earlier, the Earth's angular momentum makes it very difficult to stop its rotation. However, there have been theoretical proposals for slowing or reversing the Earth's rotation, such as using massive rockets to push against the Earth's rotation. However, these methods are currently not feasible and would have unpredictable consequences.

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