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Can Earth's rotation generate power? Physicists divided over controversial claim
- threeseed 2y agoCurrent = 25.4 ± 1.5 nA, Voltage = 17.3 ± 1.5 µV. Making total power for the 30cm shell = 0.44 picowatts.
- MichaelRo 2y ago[flagged]
- serm56 2y agoI don't see a problem with the LLM answer. The field near an FM station can reach 100mV or more. The maximum safe exposure levels for general public at 100MHz is 30V/m according to standards.
- rcxdude 2y agoIt's easy to lose a sense of scale in a field which usually works in logarithmic scales. Signals can easily vary by more than 40dB, and it's easy to forget that's a factor of 100 already, and another 40-60dB is not crazy in edge cases. (OTOH ~100uV is a much better estimate of what you'll be seeing from a 'good' FM radio signal)
- userbinator 2y agoThe part about FM sounds like BS, but much more than 1V at the antenna is definitely possible if you're close to an AM station, enough to cause unintentional receivers to emit sounds.
- MichaelRo 2y agoWell, I'm expecting an average case, not "playing AM radio with grass", because in the vast majority of the cases, antennas won't be situated within a few meters of the radio tower: https://www.youtube.com/watch?v=b9UO9tn4MpI https://www.youtube.com/watch?v=b9UO9tn4MpI
- deleted 2y ago[deleted]
- cedws 2y agoStill more net energy than fusion reactors have ever produced.
- ChrisNorstrom 2y agoMy 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?
- chrisjj 2y ago> would that accidentally slow the Earth's rotation No. Incidentally :)
- 6510 2y agoI'm not saying that is why we left Mars.
- aeve890 2y agoYeah, after making an oopsie with a runaway greenhouse effect in Venus. All this has happened before and it will happen again.
- amarant 2y agoAh yes, the Battlestar Galactica theory of life's origins on earth
- fallingknife 2y agoIt's definitely not why we left Mars because Mars still rotates every 24:30. We left Mars because of the hostile Martians, of course.
- foxglacier 2y agoNo 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.
- FilosofumRex 2y ago
- Kerbonut 2y agoI 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.
- evan_ 2y agoSounds like solar power with extra steps
- BurningFrog 2y agoThis kinda sorta how auroras/northern lights work.
- vessenes 2y agoThis 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.
- ninetyninenine 2y agoWouldn't this slowly slow the earths rotation down? Let's say everyone tried to build power plants using this.
- ziofill 2y agoWouldn'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)
- Retric 2y ago0.44 picowatts = 4.4e-13 watts so not in a detectable fashion before the sun consumes the earth billions of years from now.
- ziofill 2y agoWell, the watts that come out of the rotational energy must match the ones we need, for energy conservation.
- Retric 2y agoSure, but there’s no “eventually” it happens instantly. The only way you’ll care about what happens eventually is if you’re concerned about some detectable result. Meanwhile individual rocket launches to Mars extract like 10^18+ times as much energy as this will over it’s lifespan and those still aren’t detectable.
- frozencooler 2y agoDoesn’t driving west to east on a highway slow down the Earth’s rotation, via the power transferred into the ground?
- BurningFrog 2y agoOnly while you're driving.
- amarant 2y agoYes, but that energy is returned when you break
- throwaway48476 2y agoWould this reduce the magnetic field stength allowing more cosmic rays to reach the surface.
- xattt 2y agoI, for one, look forward to ground-level auroras.
- deleted 2y ago[deleted]
- Panda_ 2y agohttps://archive.is/5GHWF https://archive.is/5GHWF
- dang 2y agoThe paper is here: https://arxiv.org/abs/2503.15790 https://arxiv.org/abs/2503.15790 (via https://news.ycombinator.com/item?id=43520716 https://news.ycombinator.com/item?id=43520716, but we merged that thread hither)
- nyc111 2y agoWhy does the earth have a magnetic field?
- frozencooler 2y agoThe earths rotation creates it. Or was this rhetorical.
- nyc111 2y agoNo, it was a serious question. Does anything that rotates create a magnetic field even if it is not an electrical material?
- pmontra 2y agoThe iron core but there are many open questions https://news.mit.edu/2020/origins-earth-magnetic-field-mystery-0408 https://news.mit.edu/2020/origins-earth-magnetic-field-myste...
- cyphax 2y agoIn case of Earth, Wikipedia describes [1] it as being "[..] generated by electric currents due to the motion of convection currents of a mixture of molten iron and nickel in Earth's outer core". This makes Earth a geodynamo [2]. (The aforementioned Wikipedia page is actually really long and detailed, a lot more than I would have thought) [1] https://en.wikipedia.org/wiki/Earth%27s_magnetic_field https://en.wikipedia.org/wiki/Earth%27s_magnetic_field [2] https://en.wikipedia.org/wiki/Dynamo_theory https://en.wikipedia.org/wiki/Dynamo_theory
- fallingknife 2y agoNo, otherwise Mars would have a magnetic field just like Earth.
- beeforpork 2y agoBasically: moving electric charge = magnetic field. It's equivalent, that's why it's called electromagnetism: it's one and the same force. The Earth rotates, liquid iron (inside Earth) flows => a current flows in the iron => there is a magnetic field.
- EncomLab 2y agoIt's incredible the lengths humanity is willing to go to avoid adopting nuclear energy - despite the US navy driving mobile reactors millions of miles over the last 70 years.
- deepfriedchokes 2y agoThe Navy isn’t constrained by economics. Nuclear doesn’t make sense economically compared to things like solar and batteries.
- SecretDreams 2y ago> things like solar and batteries. Magnets too - let's just go magnets everywhere. Reality is solar isn't viable everywhere. And it's not optimal to put it in places where you use the sun to grow food. We should follow a holistic approach. * Wind where it's windy. * Solar where it's sunny - ideally on buildings/away from farms. * Hydro where possible. * Nuclear where it makes sense, i.e. stable geography, low occurence of natural disasters, lots of land. * Some natty gas plants for overflow - not saying commission new ones or prioritize natty, but it's sensible to utilize existing peaked plants. I'm not a big fan of large scale battery storage solutions, but they can work sometimes. I think they're more sensible for residential/commercial use and, when paired with solar, can really help add robustness to the grid. But, for mega energy storage, I think hydro based solutions are more sensible.
- djmips 2y agoWhy doesn't Geothermal make your list?
- SecretDreams 2y agoGreat question! Mostly, because I forgot. Second, it's pretty expensive for the gains you get - I'd rather favour it for use in heat pumps; but it makes sense for some regions.
- 2y ago
- npodbielski 2y agoI wonder how many wats of power we would be able to generate before earth slows down for i.e. 1 second longer day.
- IshKebab 2y agoThat's easy to work out but I can tell you not it's going to be more than we will ever use.
- barbazoo 2y agoTypical human response
- Beijinger 2y agoYou have no idea, what amount of energy we will be able to use the long run.
- ada1981 2y ago220, 221, whatever it takes.
- janpot 2y ago"640K ought to be enough for anybody"
- tiagod 2y agoWe have potentially millions or billions of years of history in front of us. If we find a way and a motive to have self-sustaining communities outside this planet, and considering our own history, it looks at least plausible that we will continue spreading, after dominating an entire planet against the brutal odds of natural selection, which we basically hacked with our consciousness to reach this state. Keep in mind that energy is not electricity. When a rocket is burning huge amounts of fuel to reach orbit, that's energy we're using, a lot of it.
- af78 2y agoI'm taking figures from https://en.wikipedia.org/wiki/Rotational_energy https://en.wikipedia.org/wiki/Rotational_energy Moment of inertia of the Earth: I=8.04e37 Angular velocity, with sidereal rotation period of 23.93 hours: ω0=2π/(23.93 × 3600) Angular velocity, with sidereal rotation period of 23.93 hours plus one second: ω1=2π/(23.93 × 3600 + 1) Rotational energy difference: .5 × I × ω0 ** 2 - .5 × I × ω1 ** 2 ≈ 4.96e+24 J For comparison, according to https://ourworldindata.org/energy-production-consumption https://ourworldindata.org/energy-production-consumption the total amount of energy consumed on Earth in 2023 was 180E3 TWh i.e. 6.48e+20 J Slowing down the Earth by one second would be equivalent to 7661 times this amount.
- j45 2y agoThe topic is very interesting. The spin of science, is not. Side story: What's to argue over? There's no shortage of scientists with breakthroughs who are pretty much abused by their profession and colleagues, sometimes for decades, simply for exploring possibilities and capabilities that are more than safe and conservative and incremental. Either it's true, or it's not, and it can be explored, or not. Division breeds who is right and wrong, not what is right or wrong. Maybe it can be proven, maybe not. Maybe it's true and we don't understand it yet. The naysayers might just not be wanting someone else to succeed.
- j45 2y agoHappy to be downvoted over silent disagreement. Even happier to get input and maybe learn.
- vessenes 2y agoI didn't downvote, but since you asked for feedback, I'd venture a guess that most who did think your post doesn't add anything to the discussion. It's vague, not topical to the paper and isn't falsifiable. A related topic, the emDrive, which had plenty of controversy, is something readers of this thread want to talk about; the specifics are a better fit for this crowd than the meta questions, esp. when vaguely introduced.
- 1970-01-01 2y agoA 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.
- mr_mitm 2y agoIt doesn't take any energy to maintain a static magnetic field though.
- deleted 2y ago[deleted]
- jagger27 2y agoEarth's magnetic field isn't static, though.
- mr_mitm 2y agoNegligibly so. The Sun delivers more energy to Earth in about 5 seconds than the magnetic field loses in 1,000 years.
- timewizard 2y agoThe magnetic field is coherent. The energy from the Sun is not.
- pfdietz 2y agoThe currents that produce the magnetic field are flowing in liquid metal with nonzero resistivity.
- fallingknife 2y agoEarth's rotation is also generating the power that is moving the Moon's orbit slowly away from Earth. There will be no more total solar eclipses in 600 million years because of this.
- deadbabe 2y agoSuggest a hard sci-fi story where humans abuse this so much the Earth basically stops rotating.
- owenpalmer 2y agoImagine trying to speed up the Earth's rotation!
- Rygian 2y agoI'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"?)
- Hyperboreanal 2y agoSaying what book you're talking about is kind of a spoiler now for anyone that happens to be reading its series. Are there spoiler tags on HN? <SPOILER> The Long Utopia, book 4/5 of the Long Earth series by Pratchett and Baxter. </SPOILER> The series has very meh characters/dialogue, excellent ideas and sense of nearly possibility-unlimited discovery that's executed very well, highly recommend if that's your cup of tea. Ended up skipping all the flashback chapters near the end of the series though, that felt like a load of filler
- pavel_lishin 2y agoI was wildly disappointed in that series. A great premise that fizzled out about 3/4ths of the way through the first book. I powered through, and started the second, and gave up maybe five chapters in. If the concept of world-hopping intrigues you, Charles Stross's "Merchant Princes" series does it better.
- whutsurnaym 2y agoI'm really glad to see this wasn't just my experience. I absolutely loved the premise of the first book. Every time I think about it I get the same kind of excitement I feel when I come up with the perfect idea for a D&D campaign. But the second book gathers dust on my shelf, and no matter how many times I think "I should get back into these!" I just can't. The first book ended in a fizzle and the second completely failed to keep my attention. I'll take a look at Merchant Princes and see if that's more to my liking!
- bmacho 2y agoImagine 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.
- randomNumber7 2y agoMaybe if we use the moon (and ideally get 2 more) we can build a giant generator.
- drewolbrich 2y agoThe 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.
- qnleigh 2y agoYes, but when you consider the combined system of the earth and everything that affects its orbit, angular momentum is conserved.
- themaninthedark 2y agoThere 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/700919.Signal_to_Noise https://www.goodreads.com/book/show/737628.A_Signal_Shattered https://www.goodreads.com/book/show/737628.A_Signal_Shattere...
- jaggederest 2y agoEric Nylund's books are uniformly excellent, even (perhaps surprisingly) the Halo tie-ins
- genewitch 2y agoNever heard of him
- genewitch 2y ago> The novel follows Jack Potter, a computer cryptographer tenured at the fictional Academe of Pure and Applied Sciences in Santa Sierra, California (a city assembled from the ruins of San Francisco.) The story details Jack's first encounter with an alien calling himself Wheeler who apparently wishes to trade information with humanity. > Accompanied (for a while) by "gene witch" Zero al Qaseem and data paleontologist Isabel Mirabeau, Jack establishes a corporation based around one of the technologies he was traded by Wheeler, but soon finds that there may be more to his dealings with the alien than he bargained for. Traitorous alliances, deceitful propaganda, and shady business practices are frequent elements of the novel. > "gene witch"
- genewitch 2y ago"Decent"
- yhager 2y agoBy quoting the word "Decent" you mean it is actually excellent, or is it actually poor?
- miller_joe 2y agoStrong flashbacks of Southland Tales (2006). Underrated movie with this as a core premise
- LegionMammal978 2y agoIt 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.
- api 2y agoI was about 99.99999% sure that one was bogus because it was violating bedrock conservation laws. I'm not sure that this does. AFAIK there is no conservation law that says a spinning mass can't extract power from that. Still... it would have been hilarious of the EmDrive had worked. "Well, they've progressed! Last time we checked in on the third planet in this star system its inhabitants were still using warp drives to heat food. They appear to have realized this."
- Certhas 2y agoFor the EmDrive it also was that the claimed theoretical mechanism was mathematically impossible, because it was based on equations that (like all known equations and everything ever observed) satisfy the conservation laws. That's a good question actually. Supposedly this is extracting energy from the rotational kinetic energy of the earth. I haven't looked at the paper but you'd need to worry about conservation of angular momentum here. Given that the cited physicists didn't dismiss this out of hand I assume this is accounted for somewhere...
- deleted 2y ago[deleted]
- qnleigh 2y agoWell conservation of energy says you can't extract energy out of nowhere. In the paper they claim that the extracted energy comes at the price of slowing down Earth's rotation. But then this seems to violate conservation of angular momentum... Maybe it depletes Earth's magnetic field instead?
- sroussey 2y agoThe Earths rotation already generates power for us: wind. It’s why the jet stream only goes one direction.
- cma 2y agoFoucault's pendulum also orbits in one way, but is that generating more power than put into it by starting it off?
- kurthr 2y agoAnd don't forget the tides, both solar and lunar. I'm sure a large enough mirror and photocell could get power out of the aurora borealis. An argument that the magnetic field in a location remains completely constant as the earth rotates seems bizarre, but so does the idea that it's large enough to economically extract power.
- kadoban 2y agoAre the tides caused by Earth's rotation? My understanding is they're not. I know they're a bit of an inter-related system, but I thought if anything tides mess with rotation (eventually causing tidal lock), not so much the other way around. How big are the solar tides? Never really considered that tbh. Looked it up, they're about half the size of the Lunar ones? Wild.
- aurizon 2y agoWe could use this, by adding power, to fine tune the day to eliminate leap years...;)
- mentalgear 2y agohow practical is this, eg how big would a device have to be to produce any meaningful energy?
- shadowgovt 2y agoI 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.
- deleted 2y ago[deleted]
- signa11 2y agobut _why_ does the earth rotate ?
- exabrial 2y agoThey made a really terrible movie about this. Spoiler: they nuked a bunch of stuff.
- asdefghyk 2y agoI ask, ..... Would Extracting power would have the side effect of slowing down the earths rotation ?
- dabbz 2y agoFuturama already did this episode though? It caused the Earth to stop spinning.
- K0balt 2y agoI mean… yes, the earth’s rotation can easily generate power. All you need is a gyroscope spinning in a vacuum on frictionless supports to make that work. Of course it’s only 1 revolution per day, but still, if it’s big enough… It’s hard to beat solar though.there are very few technologies that stack up better financially than “just buy more panels” in most of the populated world. Batteries are really the key.