Can Earth's rotation generate power? Physicists divided over controversial claim

[Panda_]

https://archive.is/5GHWF

[sroussey]

The Earths rotation already generates power for us: wind. It’s why the jet stream only goes one direction.

[dang]

The paper is here: https://arxiv.org/abs/2503.15790

(via https://news.ycombinator.com/item?id=43520716, but we merged that thread hither)

[ziofill]

Wouldn't this eventually slow down Earth's rotation? The rotational kinetic energy of our planet is 1/5 M * R^2 * w^2 with (approximately) M = 6e34 kg, R = 6.3e6m, w = 7.4e-5 rad/s, which gives approximately 5e36 joules. Yearly we need roughly 3e16 Wh. Yeah ok there's plenty. Woah! (also, I may be off by some orders of magnitude)

[MathMonkeyMan]

This is addressed in the last paragraph of the article:

> Even if it works, the method will not generate energy from thin air. It would tap Earth’s kinetic energy and, in doing so, cause the planet’s spinning to slow over time — although only slightly. If the technique provided all of Earth’s electricity needs, which was around 11 trillion watts in 2022, this would slow the planet’s spin by 7 milliseconds over the next century, the authors calculate. This is similar to the change in speed caused by natural phenomena such as the Moon’s pull and changing dynamics inside the planet’s core.

[DriverDaily]

Can we put energy in to speed it up?

That way a day can be 24 hours exactly instead of 23 hours, 56 minutes, 4 seconds, etc...

[frozencooler]

Doesn’t driving west to east on a highway slow down the Earth’s rotation, via the power transferred into the ground?

[Retric]

0.44 picowatts = 4.4e-13 watts so not in a detectable fashion before the sun consumes the earth billions of years from now.

[golol]

Where does the angular momentum go?

[foota]

The IERS will never stand for this!

[themaninthedark]

There was a decent science fiction serris based on this premise:

https://www.goodreads.com/book/show/700919.Signal_to_Noise

https://www.goodreads.com/book/show/737628.A_Signal_Shattere...

[watersb]

Ideally enjoyed these. Can't find them as ebooks.

The first one was where I first encountered the idea of the "One Electron Universe":

https://en.m.wikipedia.org/wiki/One-electron_universe

A major plot point of these books is an alien technology that enables teleportation by somehow tapping into the Earth's angular momentum.

[jaggederest]

Eric Nylund's books are uniformly excellent, even (perhaps surprisingly) the Halo tie-ins

[genewitch]

"Decent"

[vessenes]

This is really cool. Question for EEs / Material Scientists reading the paper - they mention you could shrink the cylinders and get the same voltage provided a "suitable material" could be found. Any back of the envelope or explanation of materials needed to make these cylinders say 1/1000th their current size? That'd be an extremely useful amount of energy when put into say a 1000x parallel array.

It seems hard to imagine that this kind of shrink-down could go on forever, but on the other hand, the earth is just sort of hurtling us around with great energy while it rotates.

[ChrisNorstrom]

My Stupid Question, please don't laugh:

If you did this on a massive enough scale, to generate serious amounts of power, would that accidentally slow the Earth's rotation down over time?

[ChuckMcM]

It isn't a stupid question, it is a good one. The answer would depend on how the field is generated in the first place.

Given a field generated by asymmetric rotation of the molten core at the center of the Earth, 'shorting it' (apply a load) would presumably affect the core's rotation. In terms of relative energy however, the poor coupling at the surface would suggest that this would be a very challenging way to divert any meaningful amount of power from the core itself. It would however have to deal with points in time where the core reverses its magnetic field. The papers on core reversals are fun to read.

I think more usefully, the presence of the voltage, might be an interesting way to localize one's location and orientation.

I remember brainstorming "off the wall" power generation ideas and one that has yet to be realized would be to inject dust ahead of a wind turbine with a collector in the back. Then using the Van DeGraf effect to generate power instead of lightning as it currently does.

[whatshisface]

They are one step ahead of you. :-)

"We previously showed that even in an extreme scenario where our civilization somehow would obtain all its electrical energy from the effect described here, Earth’s rotation would slow by <1 ms per decade [2]."

[ngruhn]

fast forward a hundert years and there is a massive culture war between the "rotation slowdown deniers" and people religiously buying "rotation friendly" products.

[marshray]

The term "generate power from Earth's rotation" is basically saying "convert kinetic energy from Earth's angular momentum". If you extract energy, by conservation of energy that energy has to come from somewhere. So yes, we would normally expect Earth's rotation to slow.

But I think if you do the math, it would be absolutely miniscule.

[6510]

I'm not saying that is why we left Mars.

[nopelynopington]

I've often wondered about a similar issue with wind power. Would enough wind turbines dampen the force of wind?

[j45]

Not stupid at all, especially if only one part of physics exists and not quantum physics.

[modeless]

Alternatively, we could speed up the Earth! Let's get rid of those pesky leap seconds!

[foxglacier]

No because of conservation of angular momentum. Maybe it would cool the Earth's interior faster than otherwise though. It's heat flow from the inside to the outside that drives the fluid flows in the mantle and generates the magnetic field.

[chrisjj]

> would that accidentally slow the Earth's rotation

No. Incidentally :)

[LegionMammal978]

It would be interesting if this works. Last time people were hyping up a tiny effect with big ramifications that can only exist due to a subtle 'loophole', it was the EmDrive stuff that turned out to be driven by measurement errors. But I'm no expert in electrostatics.

[1970-01-01]

A bad question, as it has been doing that literally (rotationally) since before life started. This power is busy generating the magnetosphere. We would not be enjoying our nice oxygen atmosphere and would be as dead as Mars if Earth's rotation wasn't also powering a dynamo.

[threeseed]

Current = 25.4 ± 1.5 nA, Voltage = 17.3 ± 1.5 µV.

Making total power for the 30cm shell = 0.44 picowatts.

[cedws]

Still more net energy than fusion reactors have ever produced.

[deadbabe]

Suggest a hard sci-fi story where humans abuse this so much the Earth basically stops rotating.

[Rygian]

I've already read one where some weird alien ants hollow out the earth to make it spin faster, and take advantage of the increase in speed to generate power somehow (maybe by building a geostationary conductive belt around the planet, that acts as the "stator"?)

[bigmadshoe]

Reminiscent of 'The Gods Themselves' by Isaac Asimov

[hammock]

Eric Nylund’s Jack Potter series. See an earlier comment

[owenpalmer]

Imagine trying to speed up the Earth's rotation!

[Kerbonut]

I had an idea somewhat related to this where we use the solar winds as a sort of road and the earth's magnetic field as a sort of rotor to convert kinetic energy from the sun into electricity.

[BurningFrog]

This kinda sorta how auroras/northern lights work.

[evan_]

Sounds like solar power with extra steps

[shadowgovt]

I have no idea on the claims here, but there is one method for extracting work from the magnetic field that I very much enjoy.

A magnetorquer is an attitude control system on a satellite that runs on electricity. Run the electricity through an electromagnet. The magnet couples to Earth's magnetic field and turns the satellite, like a compass needle.

[throwaway48476]

Would this reduce the magnetic field stength allowing more cosmic rays to reach the surface.

[xattt]

I, for one, look forward to ground-level auroras.

[npodbielski]

I wonder how many wats of power we would be able to generate before earth slows down for i.e. 1 second longer day.

[bmacho]

Imagine a massive planet spinning in empty vacuum. Can the inhabitants slow down their planet, and generate electricity?

I suspect that they can generate electricity with angular momentum with it, that can be only used to do work with the equivalent angular momentum.

[drewolbrich]

The Moon's tidal forces are already slowing down the rotation period of the Earth, which was apparently only 5 hours long about 4.5 billion years ago.

[randomNumber7]

Maybe if we use the moon (and ideally get 2 more) we can build a giant generator.

[asdefghyk]

I ask, ..... Would Extracting power would have the side effect of slowing down the earths rotation ?

[mentalgear]

how practical is this, eg how big would a device have to be to produce any meaningful energy?

[miller_joe]

Strong flashbacks of Southland Tales (2006). Underrated movie with this as a core premise