What happens if the Earth stops spinning?

[Tetsubo]

http://www.esri.com/news/arcuser/0610/nospin.html

[aeric90]

Very facinating!

[Keab42]

Indeed

[sdhonda]

There was a show about this on the Discovery channel a few weeks ago.

But ya, thank you for posting.

[meta me]

this is a terrible article yes the earth is slowing however i the ida that "slowed down and finally stopped spinning over a period of a few decades" is ludicrous and violates the laws of physics i so many whys it all so makes know mention of the moon in this like see level this is important.

[sdhonda]

this is a terrible article yes the earth is slowing however i the ida that "slowed down and finally stopped spinning over a period of a few decades" is ludicrous and violates the laws of physics i so many whys it all so makes know mention of the moon in this like see level this is important.

It's called a thought experiment.

[Master Gunner]

It uses the term "centrifugal force". Multiple times. That does not inspire confidence.

[aeric90]

It uses the term "centrifugal force". Multiple times. That does not inspire confidence.

It does doesn't it... I didn't catch that. Should be centripetal, right?

[Metcarfre]

This is why knowledge transfer is such a difficult aspect of research. You have to balance the conveyance of accurate information against the ability of the layman to understand technical terms.

[cathou]

technically dont we all die from hard radiations if the earth stop spinning ? I think that the magnetic shield that keep us all alive is mainly because the center of the earth spin...

[Elomin Sha]

I thought the earth was slowing down because the moon is moving away.

[Smeghead]

The planet could stop spinning rather quickly; but that could probebly only be caused by a major asteoid impact (I know that one of the planets in the solar system is spinning the other way around compared to the other planets and a theory was that it was caused by a big impact). However, considdering how big that asteroid would have to be... well, no one would live long enough to notice that the planet stopped spinning.

About a month ago I saw a documentary about what would happen to the planet and how it would finally end. And I couldn't help but wonder "Why do we care? The planet will be swallowed by the sun in a few billion years; mankind will be long gone by then"

[AlexanderDitto]

It uses the term "centrifugal force". Multiple times. That does not inspire confidence.

It does doesn't it... I didn't catch that. Should be centripetal, right?

...kind of, but not really. If my understanding is correct, centrifugal force is an appropriate term when discussing the fictitious outward force experienced by objects within a rotating frame of reference. In an inertial frame of reference, such a force does not actually exist, but it is often useful to consider such a force when we're concerned about objects inside the rotating reference frame, because it's a huge pain in the butt to do rotational physics within a fixed reference frame.

So, with respect to the oceans, the oceans themselves experience a centrifugal force due to the rotation of the earth which, from the frame of reference of the oceans, pushes them outwards from the planet. From an external frame of reference, we would say that the oceans require an inward centripetal force to impel their continued rotation about the fixed center of the earth, and this force is provided by gravity.

Basically, the article seems to be trying to use the reference frame of the oceans, but this:

Sea level is—and has always been—in equilibrium with the planet's gravity, which pulls the water toward the earth's center of mass, and the outward centrifugal force, which results from the earth's rotation.

is wrong and stems from a misunderstanding of how rotation works.

Also, rotational physics is bananas.

Now watch Chrusher come in and knock my understanding of this shit out of the park.

[Master Gunner]

Last I checked he was at some kind of Astrophysics Extravaganza, so he may be a little late getting here. I have no doubts that I will only understand half of what he says though.

[frozen_flame]

It's certainly an interesting thing to think about. What about temperatures, though? One side'd face the sun 24/7, and one would never see sunlight. That'd lead to huge increases/decreases in temp, right?

[aeric90]

One side'd face the sun 24/7

If the Earth stoped spinning than it would still have a day, but the day would be 1 revolution around the sun long similar to the way the sun is seem from the poles. To have one side facing the sun 24/7 the Earth would have to rotate at the same speed as revolves around the sun like Jupiter does.

[Master Gunner]

Not quite. When the same face of an object faces the object it's orbiting at all times, it's "tidally locked". The Moon is tidally locked to Earth, for example. We always see the same side of it, hence the term "The Dark (or Far) Side of the Moon", we can never see the other side of it without going out into space past it and looking back. The key thing about this is that a tidally locked object is rotating, namely, its rotational period is the same as its orbital period, so over the course of 1 day, as the Moon orbits around the Earth, it rotates 360 degrees once, which is how the same side constantly faces us.

When an object isn't rotating at all though, as it orbits around an object, it exposes different faces as it moves around. I'll try representing it in ASCII, where O is the Sun, and < is the Earth, with the arrow indicating the direction of any random point on the planet at different points in its orbit.

If it was tidally locked, it would look like this:
...V
> O <
....^

Whereas if the Earth stopped rotating completely, it would look like this:
...<
< O <
...<

[Gollom]

It's certainly an interesting thing to think about. What about temperatures, though? One side'd face the sun 24/7, and one would never see sunlight. That'd lead to huge increases/decreases in temp, right?

Pretty much. Would make for some pretty awesome windstorms.

Sadly, many of us wouldn't be around to see them, on account of our countries becoming oceans.

[His_Ryanness]

I think this is using the word equilibrium somewhat lazily

Sea level is—and has always been—in equilibrium with the planet's gravity, which pulls the water toward the earth's center of mass, and the outward centrifugal force, which results from the earth's rotation.

but it's otherwise fine. I think they're just saying that the sea level has been staying at about the same place because the balance between the Earth's gravity (or the centripetal force if you like) and the ocean's inertial tendency to want to go in a straight line (centrifugal) has remained constant for a long time. I don't think they're trying to say, for instance, that gravity and centrifugal force are actually in equilibrium (which only happens at about 36,000 km above ground AKA geostationary orbit).

From our rotating reference frame, centrifugal force does exert an apparent upward force on the oceans and on us. Doing a different thought experiment, imagine that the Earth's gravity were suddenly turned off. Assuming you held onto something, you would then see everything not tethered to the Earth (oceans, stray dogs, lawn furniture, etc.) go up, although I'm not entirely sure how fast. Of course after that they'd seem to go into a weird, curvy path because of the coriolis effect.

Disclaimer: I'm a Computer Science major. I haven't taken physics since first year.

[AlexanderDitto]

Centrifugal etc etc

Oh hai looks like you basically said what I said 5 posts up.

HIGH FIVES FOR COMPUTER SCIENCE MAJORS! *High fives*

[The Jester]

The artical itself also mentions that a day would last a year as per Master Gunner's description, which people would have noticed if they'd read the artical at less speed than a kind of galloping scan.

[AlexanderDitto]

The artical itself also mentions that a day would last a year as per Master Gunner's description, which people would have noticed if they'd read the artical at less speed than a kind of galloping scan.

I read all articles on the internet while riding a horse.

In fact, I am on a horse right now.

As we speed through this temperate wood, dust of the narrow path we traverse reaches my nostrils.

Each webpage, a tree.

Each shaft of sunlight, a keystroke.

Glorious.

[epocalypse]

my edited version of the article:

What happens if the Earth stops spinning?

Answer: Shit gets all fucked up in here, verily.

/Cool article, but one can't help but think they're kind of missing the point.

[empath]

The artical itself also mentions that a day would last a year as per Master Gunner's description, which people would have noticed if they'd read the artical at less speed than a kind of galloping scan.

I read all articles on the internet while riding a horse.

In fact, I am on a horse right now.

As we speed through this temperate wood, dust of the narrow path we traverse reaches my nostrils.

Each webpage, a tree.

Each shaft of sunlight, a keystroke.

Glorious.

Is that you, Isaiah?! Goddammit, man; quit fuckin' wit me!

It's one thing to be plastered all over the TV and lure my wife away from me via epic advertising.

But to come in HERE?

Totally breaking Whaaton's Law, man.

Not cool.

[His_Ryanness]

Centrifugal etc etc

Oh hai looks like you basically said what I said 5 posts up.

HIGH FIVES FOR COMPUTER SCIENCE MAJORS! *High fives*

Well, in retrospect, I did rehash quite a bit of what you said, but I disagreed about that quote showing a lack of understanding about how rotation works. I just think that the use of the world "equilibrium" was lazy and the rest of it was fine. I probably should have just stuck to that.

In fact, I'll edit it so that I haven't repeated anything you already said.