It’s not perpetual motion. As mass travels up the siphon, it gains orbital velocity, with the energy being extracted from the rotation of the earth; if such a siphon is put into use the earth’s rotation will slow with each bit of mass that is sent up the siphon. You can’t use such a system forever because eventually the earth will be spinning very slowly. However, given the magnitudes involves, we could send up an awful lot of mass (according to human-scale sensibilities) while slowing the earth down only a tiny, tiny bit.
And while such a system is theoretically possible (i.e. it’s not perpetual motion and doesn’t violate any laws of thermodynamics), it’s not at all practical (i.e. you won’t be seeing one built anytime soon for any reason).
I think what you’re referring to in the OP is the coriolis force that makes flows like the gulf stream possible?
As the earth turns, so does the liquid on the surface. If that liquid moves toward the pole, it’s rotational velocity is greater than that of the surface it is on, so it is deflected eastward (ant-rotational) This force increases as you move closer to the poles. The rising water of the Gulf of Mexico as it heats moves, thus deflected East and North to flow over to northern Europe.
Sorry - the Coriolis effect. Nevertheless extracting energy from the wind can act to slow down the Earth, to a miniscule extent at least. Or is this incorrect as well?
But it’s downhill only when you include the centrifugal force (or pseudoforce if you like). The source of the Mississippi is closer to the Earth’s center than its outlet is - if the Earth wasn’t rotating, but (magically!) retained its oblate shape, the Mississippi would flow the other way.
Of course. For those rivers the combination of effects (oblateness of the Earth, centrifugal force, and local deviations from the average oblate ellipsoidal shape of the Earth) results in northward flow.
In answer to the OPs original question - no. The water is already flowing in accordance with the combined effects of gravity and centrifugal force.
I don’t think so, I believe the sum total of all wind is zero, if it’s blowing west someplace then it has to be blowing east someplace else. The energy that causes wind comes from the sun, thus extracting that energy doesn’t effect the Earth’s rotation. However, raising the mass of the wind turbine would indeed slow the Earth’s rotation, like a figure skater extending her arms.
I have wondered if a huge circle of pipe could use the Coriolis effect to provide power.
A large diameter pipe with magnetic floaters inside it constructed in a large circle over a continent. The pipe has wire windings around it to capture induced voltage from the magnetic floaters moving inside the pipe.
I wonder about the dynamics of such a system, even without a power creating aspect. What if you just built the pipe. Filled it with water and watched. Make it big enough to go from the US Canada border, to the gulf of Mexico, and as wide.
What else would affect it? Temperature differentials, tidal forces, etc. For the sake of argument it is as close to the same altitude as possible over it’s course.
Maybe you let it get going before adding the magnets a few at a time. Give it a jump start with some pumping. Could it supply any useful amount of power?
If the flow actually works and sustains. Make a canal along side of it and put slow frieght in barges?
The Coriolis force only acts on things that are moving. If things aren’t moving, it won’t start them moving, and if friction is slowing things down, it won’t keep them moving.
And as Andy L pointed out, I wasn’t joking about the Mississippi. It only flows the direction it does because of the rotation of the Earth.
It only appears to act on objects that are moving, when in fact the force is being applied to the observer.
I’m guessing you’re suggesting that the mouth of the Mississippi is further from the center of gravity than the headwaters, due to the Earth’s oblate spheroid shape. However the oblate spheroid shape is caused by the rotation. If rotation stopped, wouldn’t the Earth form a regular sphere eventually? As that relates to the OP, Alaska to Texas is “uphill” as it were.
I disagree.
The Coriolis effect causes opposite effect north and south of the equator. You need only look at ocean currents and storm patterns to see that it has an effect. There is a rotational speed difference at different latitudes. This will induce a difference in a large circular pipe filled with a fluid, as it does in the open oceans and atmosphere. My only wonder, is how much power does it produce? Consider the power required to stop the water moving in the Pacific Ocean current.
Also. the Mississippi runs the way it does due to geography. It drains high to low. But it has reversed in past times, due to geography changing. It is for the most part, a slow river.
There does seem to be some transfer of rotational energy between a planet’s atmosphere and its surface, but it seems to be much more complex than I originally imagined. This paper by Correia, Laskar and Surgy indicates that a planet with a dense atmosphere (like Venus) will be prevented from entering tidal lock by something they call a ‘thermal tide’ in the atmosphere.
My tentative attempts to imagine this construct an atmosphere which has a different density on the sunlit side compared to the shadowed side, an imbalance which is enough to prevent tidal lock.
Venus’ dense, superrotating atmosphere is very different to Earth’s, but only in degree. This imbalance is enough to affect the rotation of the planet, however slightly.
Having said that, the majority of wind turbines on Earth are in temperate zones, where the wind blows in the same direction as the rotation; if there is any transfer of momentum possible in this situation, I think it would actually speed the planet up.
Oh. Centrifual at the equator is about 1% of the strenght of gravity. So if the slope is less than 1%, centrifugal force could possible push water up that hill… ok over 10% of the distance from pole to equator, the difference is 0.1% , so if the slope is less than 0.1%, water can run “up hill”.
The oceans do in fact bulge at the equator.
The flood plain land in Missouri is only 100 feet above sea level, and the river is narrow and deep, the water flow is in the bottom of a valley that is down inside the flood plain … So the actual bottom of the river isn’t much above sea level… It can be up hill to Louisiana and still flow that way.
The river at the Gulf is very shallow, and so its not really anything below sea level there…
The flatness of the terrain explains why the Missippi river has changed course in very large ways in the past… in fact a mere weir at one point sends water down a different river…
I’m going to try and answer both question together … may God have mercy on my soul …
If we think of the proto-Earth as a liquid, and only consider gravity, then her shape will be a perfect sphere. However, the proto-Earth was rotating, and the “centrifugal” forces at the equator would cause a bulge there. Indeed today we have the diameter of the Earth across the equator is 12,756.2 km and across the poles is 12,713.6 km … a difference of over 50 km. This means that mean sea level at the North Pole is actually 25 km closer to the center of gravity than mean sea level off the coast of Ecuador.
Even though the Mississippi river is 100 feet above mean sea level in Missouri, that mean sea level is closer to the center of gravity than the mean seal level at her mouth. If the Earth were to stop rotating, then mean sea level would equal out so that it would be all equidistant to the center of gravity (forming a perfect sphere). Thus mean sea level in Missouri would be lower than at her mouth and the river would flow northward (although her mouth would be high and dry in this situation).
As to eburacum45, we again consider the proto-Earth rotating. Neglecting the moon and sun, we can say that total angular momentum is conserved. The gaseous envelope surrounding the liquid/solid part of the Earth is rotating not because the Earth is dragging it along, but rather the gas is carrying it’s share of the angular momentum. It’s fair to say the atmosphere and liquid/solid Earth have been rotating together from the very beginning. That paper on Venus is pretty thick, and tries to explain why Venus will not become tidally locked to the sun, like our moon is tidally locked to the Earth (where one side of the moon is always facing the Earth). The conclusions are academic I believe, the dying sun will be vaporizing Venus long before any of these equilibrium states are obtained.
What are you measuring your “slope” with respect to? most people measure slope with respect to local sea level. At any given point on the earth’s surface, a plane tangent to local sea level has a component of gravity parallel to it that exactly offsets local “centrifugal” force. So if you have an upslope (moving toward the equator) measured relative to sea level, water is not going to flow toward the equator. Heck, if you have an upslope measured relative to a perfect sphere, that upslope is going to be even steeper when measured relative to sea level. I can’t think of a convenient reference surface on which water will flow uphill toward the earth’s equator.
