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Earth Science

Earth's Inner Core May Have Started Spinning Other Way (yahoo.com) 84

Posted by msmash from the closer-look dept.
Far below our feet, a giant may have started moving against us. From a report: Earth's inner core, a hot iron ball the size of Pluto, has stopped spinning in the same direction as the rest of the planet and might even be rotating the other way, research suggested on Monday. Roughly 5,000 kilometres (3,100 miles) below the surface we live on, this "planet within the planet" can spin independently because it floats in the liquid metal outer core. Exactly how the inner core rotates has been a matter of debate between scientists -- and the latest research is expected to prove controversial. What little is known about the inner core comes from measuring the tiny differences in seismic waves -- created by earthquakes or sometimes nuclear explosions -- as they pass through the middle of the Earth.

Seeking to track the inner core's movements, new research published in the journal Nature Geoscience analysed seismic waves from repeating earthquakes over the last six decades. The study's authors, Xiaodong Song and Yi Yang of China's Peking University, said they found that the inner core's rotation "came to near halt around 2009 and then turned in an opposite direction." "We believe the inner core rotates, relative to the Earth's surface, back and forth, like a swing," they told AFP. "One cycle of the swing is about seven decades", meaning it changes direction roughly every 35 years, they added. They said it previously changed direction in the early 1970s, and predicted the next about-face would be in the mid-2040s. The researchers said this rotation roughly lines up with changes in what is called the "length of day" -- small variations in the exact time it takes Earth to rotate on its axis.
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Earth's Inner Core May Have Started Spinning Other Way More

Earth's Inner Core May Have Started Spinning Other Way

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  • Don't you just HATE it when that happens!

  • Doesn't that mean someone will stick a fork in our planet we'll all get flame broiled by a can of air freshner and a bic lighter? Compasses will go crazy, airplanes will fall out the sky, etc, etc. All these effects are proven in the movie "The Core". Where's Aaron Eckhart when you need him most?

  • Help me out here (Score:4, Interesting)

    by Big Hairy Gorilla ( 9839972 ) on Monday January 23, 2023 @03:08PM (#63233008)
    So 25 billion trillion tonnes of iron which was spinning in the same direction as the outer 55 trillion quadrillion tonnes of the planet has somehow slowed down and stopped and further, has begun to spin in the opposite direction?

    Am I understanding this correctly?

    • Re:Help me out here (Score:5, Informative)

      by rpresser ( 610529 ) <rpresserNO@SPAMgmail.com> on Monday January 23, 2023 @03:13PM (#63233026)

      from TFA, since you apparently didn't bother to click:

      Abstract

      Differential rotation of Earth’s inner core relative to the mantle is thought to occur under the effects of the geodynamo on core dynamics and gravitational core–mantle coupling. This rotation has been inferred from temporal changes between repeated seismic waves that should traverse the same path through the inner core. Here we analyse repeated seismic waves from the early 1990s and show that all of the paths that previously showed significant temporal changes have exhibited little change over the past decade. This globally consistent pattern suggests that inner-core rotation has recently paused. We compared this recent pattern to the Alaskan seismic records of South Sandwich Islands doublets going back to 1964 and it seems to be associated with a gradual turning-back of the inner core as a part of an approximately seven-decade oscillation, with another turning point in the early 1970s. This multidecadal periodicity coincides with changes in several other geophysical observations, especially the length of day and magnetic field. These observations provide evidence for dynamic interactions between the Earth’s layers, from the deepest interior to the surface, potentially due to gravitational coupling and the exchange of angular momentum from the core and mantle to the surface.

      • How dare you use complicated words to explain this?
        Think of the children!

      • Re:Help me out here (Score:5, Interesting)

        by fleeped ( 1945926 ) on Monday January 23, 2023 @05:32PM (#63233508)
        When a sentence begins with "Differential rotation", you know it's not in layman's terms. ChatGPT'd to a simpler form:

        "Scientists have found out that the Earth's inner core spins a little differently than the rest of the planet. They've been able to figure this out by looking at how sound waves move through the Earth. They found that over the last decade, the inner core has not been spinning as much as it used to. They looked at old records and found that this happens in a pattern, where the inner core spins less for a while and then starts spinning more again. This happens every 7 decades or so. They also found that this pattern is connected to other things happening on Earth, like the length of a day and the Earth's magnetic field. This shows that different parts of the Earth are connected and affect each other."

        Notice the academic wank-o-speak "multodecadal periodicity" has being converted to a nice readable "every 7 decades or so".
        • *multidecadal, argh.

        • Re:Help me out here (Score:5, Interesting)

          by rpresser ( 610529 ) <rpresserNO@SPAMgmail.com> on Monday January 23, 2023 @05:46PM (#63233564)

          ChatGPT'd to a simpler form:

          My God, that's beautiful. Thank you.

          One thing that the abstract has that the translation softened for some reason:

          Abstract:

          This globally consistent pattern suggests that inner-core rotation has recently paused.

          ChatGPT:

          They found that over the last decade, the inner core has not been spinning as much as it used to.

          The techspeak sentence says the core isn't spinning now, while ChatGPT just said it's not spinning as much.

          • Re:Help me out here (Score:4, Interesting)

            by fleeped ( 1945926 ) on Monday January 23, 2023 @06:35PM (#63233706)
            Bloody hell, it's super annoying if it gets 95% right... Thanks for checking that out. Still I suppose it's useful to get the gist quickly, and then re-read with the built-up context to decode the academese. You can also use it in reverse:

            Prompt: Augment the following text to sound very academic and difficult to read: "we developed a new real-time algorithm that uses octrees and raytracing in order to accelerate caustics rendering"

            "An extensive and rigorous research endeavor was undertaken to formulate a cutting-edge real-time algorithm, which amalgamates the utilization of octree data structures and ray tracing techniques, resulting in a substantial increase in the efficiency of rendering caustics."

            I think there's scope for improvement
          • Looks like ChatGPT has it right, if one looks at the comment thread "Depends on perspective".

          • Re: (Score:2)

            by Chaset ( 552418 )

            My take on this, that the "differential" part is obscuring, and the ChatGPT seems to have accurately picked up on, is that if differential rotation is zero (the "paused" in the abstract), it's still spinning at the same rate as the rest of the earth ("not... as much" by chatGPT), and hence a little easier for the lay person to visualize.

            By restating the rotation in terms of a common reference frame, I think it was successful in making it more understandable/believable.

            Consequently, when differential rotatio

            • I agree with you, and now I blame the opaqueness of the abstract, not ChatGPT.

              I still wonder how a text prediction model could possibly figure that out.

      • from TFA, since you apparently didn't bother to click:

        Abstract

        Differential rotation of Earth’s inner core relative to the mantle is thought to occur under the effects of the geodynamo on core dynamics and gravitational core–mantle coupling. This rotation has been inferred from temporal changes between repeated seismic waves that should traverse the same path through the inner core. Here we analyse repeated seismic waves from the early 1990s and show that all of the paths that previously showed significant temporal changes have exhibited little change over the past decade. This globally consistent pattern suggests that inner-core rotation has recently paused. We compared this recent pattern to the Alaskan seismic records of South Sandwich Islands doublets going back to 1964 and it seems to be associated with a gradual turning-back of the inner core as a part of an approximately seven-decade oscillation, with another turning point in the early 1970s. This multidecadal periodicity coincides with changes in several other geophysical observations, especially the length of day and magnetic field. These observations provide evidence for dynamic interactions between the Earth’s layers, from the deepest interior to the surface, potentially due to gravitational coupling and the exchange of angular momentum from the core and mantle to the surface.

        I don't know that I've ever seen a longer version of "yes". Well done.

      • You quoted the article. Great job. Now tell us what part of that describes how the earthâ(TM)s core, which is hyper-massive, simply stops, then starts spinning in the opposite direction. Also please explain how the magnetosphere doesnâ(TM)t simply stop existing once the core stops rotating.

    • The Sun's magnetic field flips every ~11 years, so there is probably some harmonic effect. This puts the Earth flips on the odd cycle's of the Sun's flips which makes some sense.

    • Yes. Relative to earth, itâ(TM)s not spinning fast like a flywheel, but like 1 degree per year faster than earth (measured on the surface, about 12 meters per hour, but the core is a lot smaller).

      We are talking about huge masses with huge influences on each other and theyâ(TM)re not exactly coasting on water, rather interacting more like a very viscous fluid. The claim/hypothesis made here is that as earth shifts, the propagation delay of that change in the core is on the matter of decades.

      • ... Relative to earth ...

        That is the important part that yahoo skipped over and OP missed as well. Obviously, the idea of the core suddenly starting to rotate in the opposite direction in any external coordinate system, e.g. heliocentric, or fixed stars, or something like that, is such an idiotic concept the researchers likely didn't consider that anybody would make such a misinterpretation. But yahoo has journous writing for them, and one should never underestimate the stupidity of journous.

    • Re:Help me out here (Score:5, Informative)

      by spitzak ( 4019 ) on Monday January 23, 2023 @03:47PM (#63233162) Homepage

      It's not "spinning the other way", at least not what most people think of by those words. It is spinning the same direction, it just slightly varies in speed between slightly faster and slightly slower. It doesn't say but it probably does not manage anywhere near an entire extra rotation before it switches speeds.

      • Thank you very much. That makes some sense to me. I read the abstract, which rpresser was kind enough to paste for me... and frankly, and didn't get that out of it. From the abstract: "This globally consistent pattern suggests that inner-core rotation has recently paused"... paused? I get it now, any slight variations of speed of rotation of millions of billions of tons of iron is enough to have measurable effects. That's what I'm taking away.

        • The way I understand this is that the inner and outer cores both rotate in the same direction but because they are different fluids not always in sync.

          If inner core were rotating slower, then there seems to be some kind of elastic band friction effect in which the otter core slings the inner core around until it's going faster. The same force then yanks the inner core back, making it slow down until the outer cores is going faster. Rinse repeat.

          I assume this mysterious "elastic" friction like effect I've

    • Am I understanding this correctly?

      Clearly not.
      What they're saying is that two of the giant elephants standing on Great A'Tuin's back are now facing the other way.

    • So 25 billion trillion tonnes of iron which was spinning in the same direction as the outer 55 trillion quadrillion tonnes of the planet has somehow slowed down and stopped and further, has begun to spin in the opposite direction? Am I understanding this correctly?

      Not necessarily. A spinning ball that also rotates 180 degrees around a perpendicular axis ends up spinning the other way w/o stopping -- ie: turn the spinning ball upside down.

    • "Am I understanding this correctly?" -
      Yes - exactly.

      Those big numbers are relative to our human scale.
      We can observe far greater masses of complex fluids flowing and mixing and shearing in the sun, Jupiter, and Saturn. Those umpty-zillion tonnnnnes of mass are nonetheless made of atoms which respond to gravity, electromagnetic fields, friction & impulse one at a time. The bulk flow or oscillations may be different, or on a different time scale than the escape in your wristwatch or the pendulum at your

    • The article was written by someone who was stupid. The earthâ(TM)s core doesnâ(TM)t stop rotating, like the idiotic author of the article says it does.

      What the paper is saying is that the coreâ(TM)s rate of rotation relative to the earthâ(TM)s crust cycles between âoeslightly fasterâ and âoeslightly slowerâ. When the the coreâ(TM)s rate of rotation is slightly slower than the crust, the idiot author of the article calls that âoespinning backwardsâ but f

  • Depends on perspective. (Score:5, Insightful)

    by night ( 28448 ) on Monday January 23, 2023 @03:13PM (#63233028)

    Keep in mind the statement in the article "We believe the inner core rotates, relative to the Earth's surface, back and forth,".

    So the core is rotating in the same direction as the rest of the planet, but oscillates from slightly slower then the surface of the earth, to slightly faster. So not "reversing" in the literal sense of clockwise vs counter clockwise, but instead slightly slower to slightly faster.

    • Thank you, @night. I'll come out of my Pole-Shift shelter then.

  • Oh, great... (Score:5, Insightful)

    by Joce640k ( 829181 ) on Monday January 23, 2023 @03:19PM (#63233046) Homepage

    Cue the nutcases saying that the record global temperatures over the last decade were due to this and therefore global warming is fake news.

    • Comment removed based on user account deletion
  • Like Mr Humphries, fluids tend not be one way or another.
  • Or it is just a clickbait title?

  • I am pretty sure the core is not a ball of iron, just like stones sink in water, the heaviest metals when molton will make their way to the core, the outer core may be iron but the inner core will be the heaviest metals we have on the planet.

    • It's a great question. But yes, it turns out the molten core is full of iron.

      https://physics.stackexchange.... [stackexchange.com]

      (yes, that's the full link, it's cutoff like that). Short answer: you are both pretty sure and totally incorrect. Read the link answers for the physics behind why that is: there's a lot going on. There's lots of stuff that you didn't consider, like that heavier elements may be more volatile and undergo transformations under extreme heat, pressure, and combination with other elements. Iron has partic

    • Re: (Score:2)

      by pjt33 ( 739471 )

      Isn't iron the densest abundant metal by some margin, followed by the less dense aluminium?

      • I was thinking much higher up the periodic table, but you would start with copper, cobalt, nickel ... tungsten, gold, lead ... uranium, plutonium ...

  • Comment removed (Score:3)

    by account_deleted ( 4530225 ) on Monday January 23, 2023 @04:51PM (#63233362)
    Comment removed based on user account deletion

  • This is absolute total nonsense. Earth core has not stopped spinning because the Earth continues to spin as normal. Earth core control the tilt of the Earth and length of day. This is the most wild wrong news that I've seen in a while and there's been a lot of nonsense in recent years on the internet claimed to be the news.

    If people want to see a planet that has a core that has almost stopped spinning. Look no further than the planet Venus. Something happened to that planet core and its day is now 243 Earth

  • Next time you spit out such a BS clickbait headline you please google first, will you? Write "Angular Momentum is a Conservation Variable" on a sheet of paper 100 times and pin it to the wall of your dorm room. One trillion tons of iron are not going to spin the other direction easily. What the scientists did is they managed to interpret slight variations in earthquake waves by ever so slight variations in rotation speed. No mention of "the other way". Also, they did not go down and ignited some nukes to

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