# Can you use the Earth's rotation to get water to flow?

Could you use the Earth’s rotation to get or help water to flow towards the Equator? E.g. through a pipe or canal from Scotland to southern England or Alaska to Texas?

The Earths rotation is east to west, not north to south.

Yes, and the Mississippi River is proof of this. It flows from Minnesota to Louisiana because of centrifugal force.

So I guess the Rhine didn’t get the memo?

Why does the Rhine flow north?
Because Rotterdam sucks.

And all along, I thought water simply ran downhill.:smack:

Yes.
Use the wind and tides to power pumps.

The wind is partially driven by Coriolis force, so you would be using the rotation of the Earth to pump water. In fact, it appears that the wind patterns on the Earth affect the ocean currents to some extent, so this effect is already happening.

The flows of liquid and gas in the atmosphere are very, very gradually slowing down the Earth due to tidal effects, so it should be feasible to use the tides to pump water too if you absolutely wanted to.

I gather you are thinking of water being flung away from the earth’s rotational axis, the same way that a ball would tend to roll away from the center of a spinning turntable.

If the earth’s surface were a perfect sphere, this would work. The problem is that the earth’s surface, even if you smooth out all the mountains and valleys, is not a perfect sphere; it is an oblate spheroid. This is actually due to the rotation of the earth. On a planetary scale, rock isn’t that strong or rigid, and so the rotation of the earth causes the earth itself to distort pretty much the same as it would if it were a giant ball of liquid. IOW, any liquid that would have been at the poles providing a perfectly spherical shape has already flowed toward the equator and raised the ground there such that any water you pour on the ground in Glascow isn’t going to flow toward Southampton, assuming that you are considering start/end points with matching altitudes as measured with respect to sea level (sea level being that oblate spheroid shape). If instead you measured your altitudes with respect to a perfect sphere, then yes, you could get water to flow from north to south with your start/end points at matching altitudes - but you would then see that your end point was lower than your start point as measured with respect to actual sea level.

As water flows from north to south in the northern hemisphere, as in the Alaska to Texas example in the OP, its momentum has to increase as it moves further away from the North pole. In Anchorage its surface velocity is around 480 miles per hour, in Dallas it’s traveling at around 850 miles per hour. This requires an input of energy, which indicates it will not happen spontaneously. Pumping would be required.

Actually, this is the property that I was wondering if it were possible to take advantage of.

I think the force of gravity exceeds (and therefore will negate) the other forces considered here.

The Earth’s geoid is an equipotential surface, so you can’t get any energy out of its shape directly. On the other hand, tides and winds are a usable source of energy.

Nope. See here for explanation, including a vector diagram. The oblate-spheroid shape results in the surface of the earth not being normal to the gravity vector (everywhere except the equator and poles). This results in a component of gravitational force being normal to the surface, and a (small) component being parallel to the surface. The component of gravity that is parallel to the surface provides the exact amount of centripetal force needed to keep water from flowing toward (or away from) the equator.

The Mississippi river flows south because that’s the downhill path it found to the ocean. Plenty of rivers flow north, e.g. the Red River of the North, and the Nile.

I am fairly sure that Chronos was being ironic.

If he wasn’t , it’s the first dumb post I have ever seen him make.

We need an irony/tongue-in-cheek icon.

Yes it’s possible to use the earths rotation to move water, sometimes called a orbital siphon:

http://www.idlex.freeserve.co.uk/siphon/siphon.html