Rotation of Earth’s inner core oscillates back and forth over time compared to surface
The uncertainty of science: New data now suggests that the Earth’s inner core is no longer rotating faster than the planet’s outer layers — as had been measured in 1996 — but is now actually rotating slower.
Research published in 1996 was the first to propose the inner core rotates faster than the rest of the planet — also known as super-rotation — at roughly 1 degree per year. Subsequent findings from Vidale reinforced the idea that the inner core super-rotates, albeit at a slower rate.
Utilizing data from the Large Aperture Seismic Array, a U.S. Air Force facility in Montana, researcher Wei Wang and Vidale found the inner core rotated slower than previously predicted, approximately 0.1 degrees per year. The study analyzed waves generated from Soviet underground nuclear bomb tests from 1971-74 in the Arctic archipelago Novaya Zemlya using a novel beamforming technique developed by Vidale.
The new findings emerged when Wang and Vidale applied the same methodology to a pair of earlier atomic tests beneath Amchitka Island at the tip of the Alaskan archipelago — Milrow in 1969 and Cannikin in 1971. Measuring the compressional waves resulting from the nuclear explosions, they discovered the inner core had reversed direction, sub-rotating at least a tenth of a degree per year.
This latest study marked the first time the well-known six-year oscillation had been indicated through direct seismological observation.
What the data really suggests is that the core’s rotation is somewhat independent of the upper layers, so that each can vary relative to each other. This difference must carry with it some profound consequences, related to the length of the day, earthquakes, plate tectonics, and any number of other seismic phenomenon, but at the moment too little is known to tie everything together.
A bit of trivial for my readers: In 2004 I wrote an article for Natural History describing the discovery that the core rotated faster than the Earth’s upper layers. It was that article that prompted John Batchelor to invite me to appear on his show for the first time. The rest is history.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
The uncertainty of science: New data now suggests that the Earth’s inner core is no longer rotating faster than the planet’s outer layers — as had been measured in 1996 — but is now actually rotating slower.
Research published in 1996 was the first to propose the inner core rotates faster than the rest of the planet — also known as super-rotation — at roughly 1 degree per year. Subsequent findings from Vidale reinforced the idea that the inner core super-rotates, albeit at a slower rate.
Utilizing data from the Large Aperture Seismic Array, a U.S. Air Force facility in Montana, researcher Wei Wang and Vidale found the inner core rotated slower than previously predicted, approximately 0.1 degrees per year. The study analyzed waves generated from Soviet underground nuclear bomb tests from 1971-74 in the Arctic archipelago Novaya Zemlya using a novel beamforming technique developed by Vidale.
The new findings emerged when Wang and Vidale applied the same methodology to a pair of earlier atomic tests beneath Amchitka Island at the tip of the Alaskan archipelago — Milrow in 1969 and Cannikin in 1971. Measuring the compressional waves resulting from the nuclear explosions, they discovered the inner core had reversed direction, sub-rotating at least a tenth of a degree per year.
This latest study marked the first time the well-known six-year oscillation had been indicated through direct seismological observation.
What the data really suggests is that the core’s rotation is somewhat independent of the upper layers, so that each can vary relative to each other. This difference must carry with it some profound consequences, related to the length of the day, earthquakes, plate tectonics, and any number of other seismic phenomenon, but at the moment too little is known to tie everything together.
A bit of trivial for my readers: In 2004 I wrote an article for Natural History describing the discovery that the core rotated faster than the Earth’s upper layers. It was that article that prompted John Batchelor to invite me to appear on his show for the first time. The rest is history.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
I never knew about these tests in Alaska. I will have read up on them.
Funny, I remember some old Godzilla movies that made references to tests in Alaska.
My question is what is the resultant effect on the magnetic field?
Wonder if and how this is tied to the polarity flip every 200-300thousand years.
Many of us are fans of your conversations with John Bachelor. There is something about your spoken word. I went looking for your old chestnuts at https://behindtheblack.com/past-appearances-prior-to-2015/ The oldest working link I found on March 17, 2021 is not that old, https://audioboom.com/posts/7826561-more-water-mysteries-on-mars-bob-zimmerman-behindtheblack-com.
And I searched the interwebs for your 2004 Natural History magazine article about inner core super-roatation, Deep Impressions The Core of the Earth, which you say kicked off your relationship with John Batchelor in 2004. Instead I’ll have to check the library.
People say knowledge is increasing exponentially, but what of our rate of forgetting? You two are such prolific creators already, you can’t spend all your resources archiving.. So we’re in the here and now, and looking forward to another way to measure the slowing super rotation of Earth’s solid core.
Glenn McLaughlin: Yup, sadly Batchelor’s old shows when he was on WABC radio are gone. Oh well.
It was by listening to the John Batchelor show that I found out about Behind the Black and
I’ve been coming here ever since. I am always pleased when John Batchelor ( who also seems
to be a space science enthusiast ) has you on his show, Mr. Z. I am guaranteed an intelligent
discussion that will be well worth my listening time.
It is curious how talk radio still has at least some useful programming. When my mother passed
away in 2007 we closed down my parent’s house and, of course, turned off the television. I have
not watched “television” since 2007. Sometimes I see bits of CNN ( Communist News Network )
on the big screen plasma TV in the cafeteria at work. GAWD, what a mess.
Thank God for talk radio and the internet.
To Chris
Try not to worry
https://phys.org/news/2022-06-earth-magnetic-poles-flip.html
Thanks for the article Jeff
My concern is not so much about a flip in the magnetic field but a strong reduction. The article speaks to a ~10% reduction in the past 180 years. (Not sure how they got that type of resolution in magnetic strength measurements 100+ years ago) My understanding is that if the magnetic field reduces severely our atmosphere is in peril.
I thought everyone knew the earth flipped 90 degrees every 6000/12000 years?
https://suspicious0bservers.org/
(For entertainment purposes only)
Glenn / Mr. Z.,
I am saddened to discover JB’s extensive radio archive, went poof!
He does however have about 600 (audio) files uploaded to his Youtube page, which does include some Hotel Mars and Zimmerman segments, but only goes back 6 years.
The view counts are ultra-low, they must not have devoted a lot of time or effort to that page (I assume, because ya’ know, he had an extensive audio archive at WABC…)
https://www.youtube.com/channel/UCLI1Y6SG3RISMixPxBWwaug
The first question I would ask is: where are the angular momentum and kinetic energy going?
The answer is in the article:
The scientists say their model of inner core movement also explains the variation in the length of day, which has been shown to oscillate persistently for the past several decades.
The change in rotation rate of the inner core seems to be reflected in a change in rotation of the outer crust. The whole system seems to be very interesting. It would be nice to see how the model explains the transfer of the rotational momentum and energy between the inner core and the crust.
The more we learn, the curiouser we become.