[HN Gopher] Can Earth's rotation generate power? Physicists divi...
___________________________________________________________________
Can Earth's rotation generate power? Physicists divided over
controversial claim
Author : qnleigh
Score : 64 points
Date : 2025-03-30 18:41 UTC (4 hours ago)
(HTM) web link (www.nature.com)
(TXT) w3m dump (www.nature.com)
| threeseed wrote:
| Current = 25.4 +- 1.5 nA, Voltage = 17.3 +- 1.5 uV.
|
| Making total power for the 30cm shell = 0.44 picowatts.
| cedws wrote:
| Still more net energy than fusion reactors have ever produced.
| number6 wrote:
| That's untrue
| Retric wrote:
| No, it took far more electricity to make than it produces
| over any conceivable lifetime.
| ChrisNorstrom wrote:
| 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?
| 6510 wrote:
| I'm not saying that is why we left Mars.
| aeve890 wrote:
| Yeah, after making an oopsie with a runaway greenhouse effect
| in Venus. All this has happened before and it will happen
| again.
| amarant wrote:
| Ah yes, the Battlestar Galactica theory of life's origins
| on earth
| fallingknife wrote:
| It'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 wrote:
| 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.
| FilosofumRex wrote:
| Earth's rotation has been slowing down despite principle of
| conservation of angular momentum, at about 2 mille-
| sec/century. Dinos had an hour shorter days than we do now.
|
| I'm not an EE, but isn't this related to Tesla's last
| invention which bankrupted him - I believe he was working on
| electricity generation from thin air.
| qnleigh wrote:
| It's slowing down mostly because of drag induced by tides,
| which involve the sun and the moon. The total system
| including the earth, moon, sun and everything else does
| conserve angular momentum.
|
| But this paper seems to imply that Earth, isolated from
| evening else in the solar system, could be made to slow
| down. This does seem like a violation of conservation of
| angular momentum...
| fpoling wrote:
| This is poorly discussed in the article and AFAICS it
| reaches wrong conclusion.
|
| I think the energy comes from weakening of the magnetic
| field and the energy stored within it, not from slowing
| down earth rotation. Earth as the result may rotate
| faster as the moment stored in the field will be
| transferred back to Earth as in the example with a sphere
| from the article.
| qnleigh wrote:
| That would make so much more sense. So then the comments
| about only slowing down Earth's rotation by a few
| ms/century. It would deplete Earth's magnetic field, and
| likely on a much faster timescale.
|
| This would not be good...
| ChrisMarshallNY wrote:
| I once read a book ( _Signalz_ , by F. Paul Wilson), where
| someone got transmitted power working, and it was part of
| ushering in eldritch dimension-dwellers. In that book,
| Tesla was part of some kind of dark wizard cabal.
|
| Don't remember, exactly. It was a while ago.
| ChuckMcM wrote:
| 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.
| fpoling wrote:
| If one needs location, then the magnetic field can be
| measured directly. It is already considered as a potential
| alternative for GPS, https://www.electronicdesign.com/markets
| /automation/article/...
|
| The main problem is that locally measured Earth magnetic
| field varies on a daily basis and is strongly influenced by
| solar storms.
|
| A better alternative is to use variations in Earth gravity to
| improve inertial navigation. That vastly more stable.
| marshray wrote:
| 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.
| whatshisface wrote:
| 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]."
| modeless wrote:
| Alternatively, we could speed up the Earth! Let's get rid of
| those pesky leap seconds!
| ngruhn wrote:
| fast forward a hundert years and there is a massive culture war
| between the "rotation slowdown deniers" and people religiously
| buying "rotation friendly" products.
| nopelynopington wrote:
| I've often wondered about a similar issue with wind power.
| Would enough wind turbines dampen the force of wind?
| nprateem wrote:
| If a politician talks in front of a wind turbine, does it
| make a sound?
| padjo wrote:
| On a local level they absolutely do, in a wind farm one
| turbine can shadow another and reduce its output
| significantly. It makes wind farm layout a tricky
| optimisation problem. On larger scales the impact is pretty
| minimal though, there's so much energy spread over such a
| large area that significantly reducing it a global scale is
| not a concern.
| bee_rider wrote:
| Fundamentally, yes, right? For some definition of "enough."
|
| Actually, after some quick googling (so, maybe someone
| actually knows better) it seems like this is an issue where
| there's an active discussion? Maybe somebody actually
| involved in the field knows more.
|
| https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2004JD00.
| ..
|
| https://esd.copernicus.org/articles/3/79/2012/esd-3-79-2012..
| ..
|
| But that came out in 2012. I bet you could find some other
| article citing it, as rebuttals.
|
| It seems a bit implausible to think we could somehow pull
| enough energy from the wind to really matter, but then again
| carbon based climate change also seemed a bit implausible so,
| I guess, who knows?
| j45 wrote:
| Not stupid at all, especially if only one part of physics
| exists and not quantum physics.
| chrisjj wrote:
| > would that accidentally slow the Earth's rotation
|
| No. Incidentally :)
| Kerbonut wrote:
| 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.
| evan_ wrote:
| Sounds like solar power with extra steps
| BurningFrog wrote:
| This kinda sorta how auroras/northern lights work.
| vessenes wrote:
| 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.
| ninetyninenine wrote:
| Wouldn't this slowly slow the earths rotation down? Let's say
| everyone tried to build power plants using this.
| ziofill wrote:
| Ah didn't see this comment and I asked the same. Yes, right?
| The energy has to come from somewhere...
| mmooss wrote:
| https://news.ycombinator.com/item?id=43522519
| ziofill wrote:
| 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)
| Retric wrote:
| 0.44 picowatts = 4.4e-13 watts so not in a detectable fashion
| before the sun consumes the earth billions of years from now.
| ziofill wrote:
| Well, the watts that come out of the rotational energy must
| match the ones we need, for energy conservation.
| Retric wrote:
| Sure, 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 wrote:
| Doesn't driving west to east on a highway slow down the Earth's
| rotation, via the power transferred into the ground?
| BurningFrog wrote:
| Only while you're driving.
| amarant wrote:
| Yes, but that energy is returned when you break
| danillonunes wrote:
| Things get interesting when you reverse.
| logifail wrote:
| Reminds me of a glorious question from undergraduate physics:
|
| Calculate the change in the length of the Earth's day if the
| UK were to switch to vehicles driving on the right-hand side
| of the road rather than the left..
| rocqua wrote:
| It's actually driving north south that changes the rotation
| speed. Because your 'real' speed gets higher as you get
| closer to the equator, you 'steal' momentum from the earth as
| you get closer to the equator.
|
| Its effectively the same principle as a figure skater pulling
| in their arms when spinning, to spin faster.
| MathMonkeyMan wrote:
| 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.
| api wrote:
| > 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.
|
| Really puts how small we are on a cosmic scale into
| perspective.
|
| If we did it for a million years at current energy use scale
| it would shorten our day by about 1.1 seconds.
| aeternum wrote:
| Isn't friction from the atmosphere already slowing the
| planet's spin? Many weather effects like hurricanes
| ultimately derive their energy from a combination of the
| earth's rotation and thermal/uneven heating effects so I
| don't see why this is contentions.
|
| Like most things, nature is already doing it and has been for
| millions of years.
| mr_mitm wrote:
| No, that's not possible due to conservation of angular
| momentum. Only tidal effects can transfer some of it to the
| sun.
| mmooss wrote:
| How much velocity loss would be needed for an impact on the
| environment, or on some humans someplace?
| ForHackernews wrote:
| It's kind of insane how much energy is involved in big masses
| of rock flying around in space.
| foota wrote:
| The IERS will never stand for this!
| DriverDaily wrote:
| 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...
| golol wrote:
| Where does the angular momentum go?
| fsckboy wrote:
| it's the angular momentum that gets transferred to the
| earth's spin, and all the other numbers, energy, power, are
| simply how the books are balanced. GP should have asked the
| question in terms of momentum in the first place.
|
| with energy, you need to consider friction, losses,
| thermodynamics 3rd law, but with momentum it's pure.
| throwaway48476 wrote:
| Would this reduce the magnetic field stength allowing more cosmic
| rays to reach the surface.
| xattt wrote:
| I, for one, look forward to ground-level auroras.
| dang wrote:
| The paper is here: https://arxiv.org/abs/2503.15790
|
| (via https://news.ycombinator.com/item?id=43520716, but we merged
| that thread hither)
| Panda_ wrote:
| https://archive.is/5GHWF
| nyc111 wrote:
| Why does the earth have a magnetic field?
| frozencooler wrote:
| The earths rotation creates it. Or was this rhetorical.
| nyc111 wrote:
| No, it was a serious question. Does anything that rotates
| create a magnetic field even if it is not an electrical
| material?
| pmontra wrote:
| The iron core but there are many open questions
| https://news.mit.edu/2020/origins-earth-magnetic-field-
| myste...
| cyphax wrote:
| In 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
| [2] https://en.wikipedia.org/wiki/Dynamo_theory
| fallingknife wrote:
| No, otherwise Mars would have a magnetic field just like
| Earth.
| beeforpork wrote:
| Basically: 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.
| qnleigh wrote:
| This is a great question, and it's not as simple many comments
| here make it seem to be. This Veritasium video has a great
| explanation (and an enormous ball of molten sodium).
| EncomLab wrote:
| It'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 wrote:
| The Navy isn't constrained by economics. Nuclear doesn't make
| sense economically compared to things like solar and batteries.
| SecretDreams wrote:
| > 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 wrote:
| Why doesn't Geothermal make your list?
| Certhas wrote:
| What do you base all these claims on? Plenty of papers show
| Solar + wind + storage is viable practically everywhere.
|
| Also there is a ton of research on planning energy systems
| and what technology mixes make sense. This stuff has to be
| economical. Energy costs are measured in percentage of GDP.
| Simply liking nuclear doesn't make it viable. Especially in
| a world with PV meaning you can't sell energy during the
| day.
|
| There really is only one macro fact that will shape the
| energy system of the future: The price of PV modules is now
| effectively zero in rich countries. Everything else has to
| be judged by how well it complements/makes use of free
| energy during daylight hours. The geopolitical implications
| of this haven't even begun to be explored.
| mike_hearn wrote:
| The (subsidized, market dumped) price of cells may be low
| at the moment, but the price of storage, land and
| artificial inertia isn't.
|
| You can absolutely sell non-PV power during the day. Big
| power consumers sign contracts for predictable and
| reliable supply.
| DonHopkins wrote:
| Back when all my precious data was on floppy disk and hard
| drives, I HATED magnets. Now I am more ambivalent.
| Nifty3929 wrote:
| I haven't seen any data that backs that up based on general
| principals. Most of the cost is in artificially-imposed
| operational requirements - however well founded.
|
| Also, remember that nuclear, unlike solar, has a lot of room
| for improvement still, both in how it's done, and how it's
| regulated. Solar has already been tremendously optimized,
| while nuclear has not.
|
| The cost argument seems to be advances by the same people who
| impose or support the additional operational requirements,
| and who also just have a philosophical aversion to nuclear
| power.
|
| There are hundreds of nuclear power plants already in
| operation, many decades old. There have been only a very
| small number of minor accidents (3 come to mind: Chernobyl,
| Three mile island and Fukushima), in which only a few dozen
| people were killed. Nuclear, even using old technology, has
| proven to be far safer and better for the environment than
| any scalable alternative, including solar. New designs are
| even safer.
| rsynnott wrote:
| > Most of the cost is in artificially-imposed operational
| requirements
|
| Indeed. Once there was a wonderfully efficient, economical
| nuclear reactor design, better thermal efficiency than
| PWRs, could be refueled during operation, considerably
| cheaper to build... However, nobody is THAT keen to build
| more Chernobyls.
|
| (The RBMK design really was quite impressive, provided you
| weren't too concerned about, well, safety.)
|
| The economics of nuclear energy are difficult, today. So
| much of the cost is upfront that getting the investment is
| problematic; unless you have a guaranteed price per kWh, it
| really is a huge gamble.
| peer2pay wrote:
| Calling Chernobyl a minor accident is insane. We are lucky
| it wasn't worse but even then most of Europes forests are
| still polluted from the fallout. People directly killed
| during the incident is not a great indicator of incident
| severity when we're talking about environmental pollutants.
|
| Nobody died from installing asbestos insulation yet here we
| are.
| kjkjadksj wrote:
| Why do we have to be constrained by economics unlike the
| navy? The state within the state has access to nuclear
| powered ships so it is just a question of widening that
| capability to the members of the state living outside the
| walls of the keep. Not a matter of establishing precedent or
| anything. That part is done and long proven. The federal
| government even has experience managing water and power for
| entire geographical regions today.
| pmontra wrote:
| Many countries would have to buy nuclear fuel from other
| countries much like they do for gas and oil. On the other side
| very few countries can build their own solar panels so it seems
| the same sort of problem. However if you accept to depend from
| potential hostile countries at least solar panels don't do much
| harm when they fail and it takes very little effort to install
| the equivalent amount of power of a nuclear power plant. If we
| only could all get along and have a global power grid with
| always 12 hours of sunshine on it.
| devmor wrote:
| Until we solve the storage problem, the manufacture of
| batteries required to store solar power at night and during
| other low generation times is actively doing harm even
| without failing.
|
| I don't think this invalidates your point but I do think it
| is incredibly important to recognize that environmental harm
| done slowly over time is no less impactful than that done by
| a disaster.
| fallingknife wrote:
| Unfortunately the arrangement of the continents would require
| undersea transmission lines for this. Would be an interesting
| future where the Bering Strait is the most valuable real
| estate on Earth for the American-Euraisian grid connection.
| But more likely we would build fusion reactors or get over
| our nuclear phobia before building something like that.
| grepfru_it wrote:
| Solve the waste problem and you solve nuclear. Waste is still
| the giant elephant in the room and a lot of people have a fifth
| grade solution to the problem (we will bury it under ground! We
| will fly it to the sun! We will resuse it until it is no longer
| radioactive!)
|
| I used to have a neighbor who worked for the DOE, all of the
| viable solutions are blocked by people who don't want it in
| their backyard. Can't really move forward until that is
| solved..
| fallingknife wrote:
| Burying the waste is an excellent solution. We are currently
| dealing with the much more dangerous problem of hydrocarbon
| combustion waste by releasing it into the atmosphere.
| Ylpertnodi wrote:
| >Waste is still the giant elephant in the room and a lot of
| people have a fifth grade solution to the problem (we will
| bury it under ground! We will fly it to the sun! We will
| resuse it until it is no longer radioactive!)
|
| Could the waste be 'sent' into space? Bonus points for
| sending a certain human with it. Serious question, though.
| rsynnott wrote:
| This was one of the Soviet Union's proposed use for Energia
| (a super-heavy launcher which flew precisely twice before
| the Soviet Union collapsed). In practice, there would be,
| ah, challenges; no launcher ever built is reliable enough
| that anyone would be particularly comfortable with
| _launching large amounts of high-level nuclear waste_ with
| it.
| mschuster91 wrote:
| > Could the waste be 'sent' into space? Bonus points for
| sending a certain human with it. Serious question, though.
|
| Would you want a RUD of nuclear waste in the atmosphere?
| That's the key thing with sending stuff to space, we are
| nowhere near close enough in terms of reliability and cost
| to what would be needed to send the stuff away.
| bell-cot wrote:
| By "space" do you mean low earth orbit - where the stuff
| will reenter the atmosphere within (say) a century? Or
| geosync orbit - where it'll stay up there forever-ish...but
| ain't actually gone? Or _actually_ gone, like (say) Mars?
|
| IIR, the current rock-bottom (Falcon 9) launch prices are
| something like $1,000/lbs. to low earth orbit, $2,500/lbs.
| to geosync, and $6,500/lbs. to Venus.
|
| A quick Google says the US has about 88,000 _tons_ of
| radioactive waste. So - 88,000 tons = 176,000,000 lbs. =
| $176,000,000,000 just to put it in low earth orbit. And
| something like 4,600 Falcon 9 launches. (Some fraction of
| which would doubtless go badly wrong, spreading radioactive
| stuff all over the landscape.)
|
| In short - it's a cool-sounding idea. But neither the
| numbers nor the politics are remotely near viable.
| cyberax wrote:
| > Waste is still the giant elephant in the room and a lot of
| people have a fifth grade solution to the problem (we will
| bury it under ground! We will fly it to the sun! We will
| resuse it until it is no longer radioactive!)
|
| The correct solution: put it into dry casks and do nothing
| right now. Store it simple underground storage facilities or
| on the grounds of active nuclear power plants.
|
| The casks are fine for the next 300 years, and during that
| time we can either:
|
| 1. Perfect the nuclear fusion, it will provide plenty of
| neutrons to transmute the waste.
|
| 2. Perfect fast fission reactors. See above.
|
| 3. Use some of the excess of too-cheap-to-meter green energy
| for accelerator-driven subcritical fission reactors.
|
| 4. Yep, use rockets to slowly launch the waste into space. We
| can already design a storage capsule that can survive re-
| entry.
|
| In any case, we have literally hundreds of years to come up
| with a solution and there are many viable paths.
| kjkjadksj wrote:
| What problem with the waste? Reactors are working and
| generating power today for many thousands of americans.
| Whatever is being done with waste today seems to work well
| enough to continue reactor operations without any major
| headlines. Just seems to be a bit of cognitive dissonance
| here between what is claimed online and what we see today out
| in the field generating power.
| walleeee wrote:
| Some MSRs can consume spent nuclear fuel, that's a 7th grade
| solution at least
| npodbielski wrote:
| I wonder how many wats of power we would be able to generate
| before earth slows down for i.e. 1 second longer day.
| IshKebab wrote:
| That's easy to work out but I can tell you not it's going to be
| more than we will ever use.
| barbazoo wrote:
| Typical human response
| Beijinger wrote:
| You have no idea, what amount of energy we will be able to
| use the long run.
| ada1981 wrote:
| 220, 221, whatever it takes.
| janpot wrote:
| "640K ought to be enough for anybody"
| af78 wrote:
| I'm taking figures from
| 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:
| o0=2p/(23.93 x 3600)
|
| Angular velocity, with sidereal rotation period of 23.93 hours
| plus one second: o1=2p/(23.93 x 3600 + 1)
|
| Rotational energy difference: .5 x I x o0 ** 2 - .5 x I x o1 **
| 2 [?] 4.96e+24 J
|
| For comparison, according to 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.
| adalacelove wrote:
| According to Wikipedia [1] we consume 9717 Mtoe or equivalently
| 408 TJ (per year, although it is not explictely stated, which I
| find annoying).
|
| The earth moment of inertia is about I=8e37 kg m2 [2]
|
| The energy extracted by a slowdown of angular speed from wa to
| wb would be 1/2 I(wa2-wb2).
|
| Approx wa=2pi/86400 and wb=2pi/86401. Energy extracted:
| 4.9e24J=4.9e12TJ.
|
| We would have energy for about 12 billion years.
|
| If I double check with Kagi's assistant with Claude 3.7 (I'm in
| my phone and I could easily have made an error) it starts with
| my exact reasoning and figures but messes up final numbers (so
| close!!!) to give a total of 40 billion years, which
| nevertheless is the correct order of magnitude.
|
| [1]
| https://en.m.wikipedia.org/wiki/World_energy_supply_and_cons...
|
| [2]
| https://scienceworld.wolfram.com/physics/MomentofInertiaEart...
| mmooss wrote:
| https://news.ycombinator.com/item?id=43526555
| j45 wrote:
| The 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 wrote:
| Happy to be downvoted over silent disagreement.
|
| Even happier to get input and maybe learn.
| vessenes wrote:
| I 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 wrote:
| 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.
| mr_mitm wrote:
| It doesn't take any energy to maintain a static magnetic field
| though.
| jagger27 wrote:
| Earth's magnetic field isn't static, though.
| mr_mitm wrote:
| Negligibly so. The Sun delivers more energy to Earth in
| about 5 seconds than the magnetic field loses in 1,000
| years.
| deadbabe wrote:
| Suggest a hard sci-fi story where humans abuse this so much the
| Earth basically stops rotating.
| Rygian wrote:
| 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"?)
| Hyperboreanal wrote:
| Saying 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
| hammock wrote:
| Eric Nylund's Jack Potter series. See an earlier comment
| owenpalmer wrote:
| Imagine trying to speed up the Earth's rotation!
| bmacho wrote:
| 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.
| randomNumber7 wrote:
| Maybe if we use the moon (and ideally get 2 more) we can build
| a giant generator.
| drewolbrich wrote:
| 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.
| qnleigh wrote:
| Yes, but when you consider the combined system of the earth
| and everything that affects its orbit, angular momentum is
| conserved.
| themaninthedark wrote:
| 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...
| jaggederest wrote:
| Eric Nylund's books are uniformly excellent, even (perhaps
| surprisingly) the Halo tie-ins
| LegionMammal978 wrote:
| 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.
| api wrote:
| I 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 wrote:
| For 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...
| sroussey wrote:
| The Earths rotation already generates power for us: wind. It's
| why the jet stream only goes one direction.
| cma wrote:
| Foucault's pendulum also orbits in one way, but is that
| generating more power than put into it by starting it off?
| kurthr wrote:
| And 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 wrote:
| Are 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.
| bmm6o wrote:
| The short answer is that there would still be tides without
| rotation, but with a period based on the lunar cycle. We
| have daily tidal effects, the moon can't do that by itself.
| kadoban wrote:
| Ah I see, that makes sense. Thanks.
| babyent wrote:
| Is it possible to speed up the wind?
| righthand wrote:
| Sure, cause constant heating and cooling and loop it.
| _dain_ wrote:
| Yes, run power to wind turbines to use them as giant fans
| peterashford wrote:
| Wind power is mostly due to solar energy. Earth's rotation
| contributes a very small amount and even that smaller effect is
| more located in the upper atmosphere where we don't collect
| wind power versus solar caused pressure gradients
| rokkamokka wrote:
| While true, if the earth stopped rotating the sun would also
| stop being "evenly" distributed around the globe, which would
| affect wind patterns a lot
| IncreasePosts wrote:
| Isn't that more of the sun+rotation?
| fsckboy wrote:
| a substantial amount of wind is also caused by (differential)
| solar heating: that's why wind doesn't only go in one direction
|
| if you've ever spent time at the seashore, the wind comes in
| off the sea during the day (because of rising thermals on the
| land side) and blows back offshore at night (because the land
| cools and the sea is now warmer) that time in between the air
| is dead-still, and that's when the swarms of gnats can find
| you.
| aurizon wrote:
| We could use this, by adding power, to fine tune the day to
| eliminate leap years...;)
| ada1981 wrote:
| Interesting. Yes could we put power into a similar system and
| accelerate the rotation?
| mentalgear wrote:
| how practical is this, eg how big would a device have to be to
| produce any meaningful energy?
| miller_joe wrote:
| Strong flashbacks of Southland Tales (2006). Underrated movie
| with this as a core premise
| shadowgovt wrote:
| 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.
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