The Bizarre Behavior of Rotating Bodies, Explained

Spinning objects have strange instabilities known as The Dzhanibekov Effect or Tennis Racket Theorem - this video offers an intuitive explanation.
Part of this video was sponsored by LastPass, click here to find out more:
Prof. Terry Tao's Math Overflow Explanation:
The Twisting Tennis Racket
Ashbaugh, M.S., Chicone, C.C. & Cushman, R.H. J Dyn Diff Equat (1991) 3: 67.
Janibekov’s effect and the laws of mechanics
Petrov, A.G. & Volodin, S.E. Dokl. Phys. (2013) 58: 349.
Tumbling Asteroids
Prave et al.
The Exact Computation of the Free Rigid Body Motion and Its Use in Splitting Methods
SIAM J. Sci. Comput., 30(4), 2084-2112
E. Celledoni, F. Fassò, N. Säfström, and A. Zanna
Animations by Iván Tello and Isaac Frame
Special thanks to people who discussed this video with me:
Astronaut Don Pettit
Henry Reich of MinutePhysics
Grant Sanderson of 3blue1brown
Vert Dider (Russian ALthe channel)
Below is a further discussion by Henry Reich that I think helps summarize why axes 1 and 3 are generally stable while axis 2 is not:
In general, you might imagine that because the object can rotate in a bunch of different directions, the components of energy and momentum could be free to change while keeping the total momentum constant.
However, in the case of axis 1, the kinetic energy is the highest possible for a given angular momentum, and in the case of axis 3, the kinetic energy is the lowest possible for a given angular momentum (which can be easily shown from conservation of energy and momentum equations, and is also fairly intuitive from the fact that kinetic energy is proportional to velocity squared, while momentum is proportional to velocity - so in the case of axis 1, the smaller masses will have to be spinning faster for a given momentum, and will thus have more energy, and vice versa for axis 3 where all the masses are spinning: the energy will be lowest). In fact, this is a strict inequality - if the energy is highest possible, there are no other possible combinations of momenta other than L2=L3=0, and vice versa for if the energy is the lowest possible.
Because of this, in the case of axis 1 the energy is so high that there simply aren't any other possible combinations of angular momentum components L1, L2 and L3 - the object would have to lose energy in order to spin differently. And in the case of axis 3, the energy is so low that there likewise is no way for the object to be rotating other than purely around axis 3 - it would have to gain energy. However, there's no such constraint for axis 2, since the energy is somewhere in between the min and max possible. This, together with the centrifugal effects, means that the components of momentum DO change.


  • Moses Salazar
    Moses Salazar15 minuta më parë

    We have moon

  • Moses Salazar
    Moses Salazar18 minuta më parë

    Wow 😱

  • Rathonise Riingeathone
    Rathonise Riingeathone43 minuta më parë

    Yeah remember my passwords that’s how they work show them to strangers so I’ll feel secure

  • Matt Frye
    Matt Frye2 orë më parë

    What if the bottles were filled with mercury?

  • im aidan
    im aidan5 orë më parë

    Those hot spots on Mars looked like pascals triangle

  • Swastik Bhoyar
    Swastik Bhoyar5 orë më parë

    Also I learned that the Earth won't flip on it's axis because it already did a short time after it's creation, and also probably ones after the big rock created into it and made the moon, so it's currently spinning in the lowest kinetic energy state i.e. greatest moment of inertia

  • Swastik Bhoyar
    Swastik Bhoyar5 orë më parë

    I learned about the moment of inertia and state of it for spinning objects along with the intermediate axis theorem, so it's a lot of good info, would love if maths was this easy to understand

  • badr Tetouani
    badr Tetouani6 orë më parë

    But why there is no real pecture of round earth

  • Olorin Mithrandir
    Olorin Mithrandir6 orë më parë

    The earth's not going to flip over because it's flat

  • majormax 37
    majormax 377 orë më parë

    I'm not even kidding I noticed that when I was about 7 years old and I just thought that I wasn't good enough at flipping rackets to make it stop rotating

  • Usual Suspects
    Usual Suspects8 orë më parë

    Why is there a baby bottle on the spacecraft?

  • Noblesse Oblige
    Noblesse Oblige13 orë më parë

    How about when 400 ft of ocean water is redistributed to the north and south poles as ice as was during Ice Age 13,000 years ago. How would that affect earth?

  • Roger Warton
    Roger Warton14 orë më parë

    Also wouldnt we start seeing the sun rising in the west or have opposite seasons from what we normally would if the earth could randomly flip? I am sure we would see changes with our relation to things in space.

  • SlickJayB
    SlickJayB14 orë më parë


  • Kamaljeet Singh Mander
    Kamaljeet Singh Mander16 orë më parë

    I understood as much as I have understood my wife.

  • Pierre-Alain Dorange
    Pierre-Alain Dorange17 orë më parë

    Thanks, very interesting vidéo, but... I got 4 ads interruption plus yours (acceptable it was yours). The others (4 in 15 minutes) was from ALthe and are quite disturbing ; i never had 4 ads in a short vidéo before...

  • KM
    KM18 orë më parë

    NOOOOO! At 7:31 you mention "centripetal forces". THERE IS NO SUCH THING!!! Centripetal terms are kinematic effects; they arise from the acceleration expressions (omega x [omega x X]) and not from the force side of Newton2. And at 7:44 you mention "centrifugal forces". Dear Lord. You are my worst enemy! I just finished teaching a first year graduate course in 3d, particle and rigid body dynamics (in which we dealt extensively with multiple rotating reference frames) and you're casually - and incorrectly - talking about things these things, further sowing long-term confusion rather than elucidating facts about basic physics. Oh, my achin' back! By the way, a simple description of Euler's equations doesn't require any high-end mathematics (once you've taken all of the necessary derivatives) ... and can be used to explain what's going on. Don't shy away from math. It's our friend (and it has the added bonus of providing a way to quantify what we see).

  • justonlyweb
    justonlyweb19 orë më parë

    Too many ads really detract from this video!!!

  • GetMoGaming
    GetMoGaming19 orë më parë

    It seems obvious to my mind while viewing the wingnut that it's something to do with slight variations in mass causing the rotation to become unstable and flip. It seems like it should happen. Does this mean I'm a genius?

  • Truck Driver
    Truck Driver19 orë më parë

    Please do not spin a revolver.

    COSMOS23 orë më parë

    So if its spun on the y axis perfectly does that mean this effect wont happen?

    THEY LIVE23 orë më parë

    FAKE propaganda BS space is made in hollywood basement space is a cartoon ...

  • Divyesh Rane
    Divyesh RaneDitë më parë

    So is it possible that earth has fliped that's y dinosaurs don't exist?😂

  • Brandon Brodbeck
    Brandon BrodbeckDitë më parë

    I thought I was special and that I was making do that with skill now I find out it will do it with anyone dam

  • Clecy Conner
    Clecy ConnerDitë më parë

    Most amazing physics discovery since the Slinky..

  • Winfried Wilcke
    Winfried WilckeDitë më parë

    This effect (that rotation around the L2 axis is unstable) nearly killer Chuck Yeager in a high altitude (about 100 000') in a F104 Starfighter jet. That was long after his Mach 1 flight. He survived by bailing out, but barely.

  • Alexander Rau
    Alexander RauDitë më parë

    I noticed this effect while flipping my knife and my mobile phone that reminds me of this video Thank you for youre work Greetings from Germany 🇩🇪

  • Winfried Wilcke
    Winfried WilckeDitë më parë

    Oh my, reminds me of my Physics 101 (Mechanics of rigid bodies). I was and still am astounded that something seemingly so simple is so complicated. If one wants to drown in such questions, go and read technical papers on heliccopters!

  • Gabriel Preda
    Gabriel PredaDitë më parë

    You can actually do something cool at home. Just grab a big empty plastic bottle, and hold it horizontally so that the cap is pointing away from you. Then throw the bottle so it's making a backflip, but also give some spin to it so it rolls in the air. You will see that the ends draw a circle in the air. If you throw it with a lot of roll and a bit of flip, you will find that the cap will never point towards you!

  • Thomas Henry
    Thomas HenryDitë më parë

    Absolutely incredible video!!! Thank you 🥰🥰🥰❤️

  • Versus Battle
    Versus BattleDitë më parë

    Scientists are scary they show you something, then you agree and then somehow they always tell you how it's eithet gonna destroy earth or do some mass destruction and you can't even deny 😱😂🖐 For example, Einstein was like, e=mc^2......normal peoples - 🙏🙏🙏🙏🙏 clap clap clap Einstein - that's how even one atom of hydrogen can destroy whole city ☺😂✌

  • Piyal Perera
    Piyal Perera2 ditë më parë

    A complex theorem explained in an understandable manner. Thoroughly enjoyed. Thanks!

  • rich4444hrsm
    rich4444hrsm2 ditë më parë

    13:45 ...stable, for now? ;)

  • Patrick Kilduff
    Patrick Kilduff2 ditë më parë

    Try this. Twist a basketball as You push down'bounce' ball. The ball spins in opposite direction as it goes up

  • Rob Orchiston
    Rob Orchiston2 ditë më parë

    "So the earth won't flip - its spinning about the axis with the maximum moment of inertia". That sounds like a simplied mathematicians explanation and didn't provide any evidence the earth can't flip. The earth is not an asteroid. It is a very dynamic elastic system with a molten core that has surges of molten movement, and plate tectonics that cause large bodies far from the center to migrate. Then there are shorter term effects such as the earth redepositing large amounts of moisture such as glaciers aroind the planet. For example the polar ice sheet is currently 3km thick sure not much compared to the 12000km diameter of the earth but the point is the earth look relatively static in our human viewframe but it is far from static. Look at even the 3 gorges dam filling creating a momentary imbalance. So I don't think a simple mathematical equation is even close the proving the earth can't flip. Maybe we should try modeling more dramatic scenarios that prove that the earth actually could flip such as adding larger amounts of polar ice or extreme mountain buildup with plate tectonics causing 100,000m high mountains. So many variables to test. It may help explain a lot of things that happen on earth such as the geological time periods Cretaceous, Jurassic, Triassic, Permian etc which almost occur with approximate regulariy. I shall make it my ambition to prove you wrong that the earth can't mathematically flip. Your math may be right at a snapshot in time but far too simple for something as complex as earth.

  • taher munther
    taher munther2 ditë më parë

    i understood nothing, but i agree, yes

  • Fawaz N
    Fawaz N2 ditë më parë

    Islamic profit Mohammed prophesy that the sun rise ☀ from west at the end times... Meaning earth well reverse it polarity.. Is it magnatic or is it this big planet ☄ comet that might pass and change the internal magma location.. So massive earthquake would happen and some plates will loss it support pressure leading to massive collapse of big cities... We don't know /this unstable movement can happen if large mass pass our planet effecting its liquid magma core or NoT.. We wait and see

  • Fawaz N

    Fawaz N

    2 ditë më parë

    @Lumalee it will /the Question is when? /maybe not in our lifetime or...?

  • Lumalee


    2 ditë më parë

    Yeah lol that wont happen

  • macforme
    macforme2 ditë më parë

    I am so glad I watched to the I can rest assured that Christmas won't be in summer. Thanks !!!! - Happy Californian

  • kennith hackett
    kennith hackett2 ditë më parë

    I`m curious to see how lord kelvin`s thunderstorm would work in space with the magnetic property's it may prove to be too complex attempting to generate a stream would the can collect the water?

  • Mahir Balushi
    Mahir Balushi2 ditë më parë


  • splee99
    splee992 ditë më parë

    Great video.

  • Gerrie Niemand
    Gerrie Niemand2 ditë më parë

    but what if u move large quantities of weight from the one part of earth to the others , e.f all of the oil tankers coming together in the middle of the Atlantic sea, surely you will create a mass slighlyt off the center of the y axis ?

  • Mark Millard
    Mark Millard2 ditë më parë

    So during the next ice age, when the water is reduced around the equator and accumulates near the North and South pole to a thickness of miles, it won't affect the moment of inertia of the earth? LOL here comes the flip, in 20 million years. Global warming contributes to maintaining a stable axis of rotation. I will continue to do my part to save humanity. LOL

  • Brian Josephson
    Brian Josephson2 ditë më parë

    Your sponsor LastPass used to be very good, but recently they decided you'd have pay a monthly sum to be able to use it both on a mobile device and on a laptop, so passwords can no longer be shared between the two with the free version. Bummer!

  • Lumalee


    Ditë më parë

    @Brian Josephson yeah but dont complain if the free version has drawbacks

  • Brian Josephson

    Brian Josephson

    2 ditë më parë

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  • Lumalee


    2 ditë më parë

    So.. pay then

  • marshalcraft
    marshalcraft2 ditë më parë

    The answer is compact I admit, however, it's relies on non inertial reference frame and ficticious forces.

  • Chris Stephens
    Chris Stephens2 ditë më parë

    What a great channel! Thank you!

  • St Ballz
    St Ballz2 ditë më parë

    Why is there a rectangular plane on the tennis racquet net ? Doesn't that catch air and change the course of the rotation ?

  • btntx
    btntx2 ditë më parë

    So would this still happen if the object were perfectly balanced?

  • Liveit ca
    Liveit ca2 ditë më parë

    have a look at the latest modeling of the earths interior....

  • Dave Woff
    Dave Woff3 ditë më parë

    I noticed this flipping wrenches 20years ago. I just assumed it was the way I was flipping them but no matter how I did it it never I never could stop it, now I know

  • Nonconcensusical
    Nonconcensusical3 ditë më parë

    They say there isn't precession in Space, only in a magnetic field. Maybe this is precession in Space, just flipping?

  • Markus Haapala
    Markus Haapala3 ditë më parë

    what if we build something very heavy in the poles. That would flip the earth. how much mass would it need?

  • Lumalee


    2 ditë më parë

    @Ayatollah Sha’Nay-Nay no, because it would take millions of years for that to happen even if it did

  • Ayatollah Sha’Nay-Nay

    Ayatollah Sha’Nay-Nay

    2 ditë më parë

    there already is something very heavy at the poles: its called ice. Terrified yet?

  • Michael Albany
    Michael Albany3 ditë më parë

    If the intermediate moment of inertia are actually aligned perfectly in and not off axis at all, would it not then spin continuously without flipping? Speaking mathematically of course; nothing is perfect.

  • i_m_0p
    i_m_0p4 ditë më parë

    I wannaa see earth flipping 🤣

  • Dustin Fette
    Dustin Fette4 ditë më parë

    Okay but what if we had a bomb big enough to shake the Earth thus causing the rotation to become unstable?

  • Sonorous Guitars
    Sonorous Guitars4 ditë më parë

    I experienced this with a racket when I was eight in 93’ and couldn’t explain it. My neighbor told me to stop smoking dope when i told him..........well screw you Carl!!

  • Paul Denize
    Paul Denize4 ditë më parë

    You showed a liquid filled object spinning about the first axis. But each object only had 2 axis of inertia. What if it has 3 (say a cellphone shaped box filled with water). Does it go from the 1st to 2nd or directly to the 3rd axis?

  • Onddu22
    Onddu224 ditë më parë

    I noticed this when i was like 10, when i was flipping books. I was pretty confused what caused it until i found this video.

  • Mark Thomas
    Mark Thomas4 ditë më parë

    Do what happens when the ice caps melt, how does that affect the maximum moment of inertia?

  • Sky High
    Sky High4 ditë më parë

    I just came here cause I did the spinning thing EVA experiment in KSP and was curious lol

  • Graham Tritt
    Graham Tritt4 ditë më parë

    The flip does not change angula momentum, that means the object after flipping is still spinning round its axis in the same direction (either clockwise or anticlockwise, seen from the same distance away). BUT THE EARTH MODEL FLIPS DIRECTION! I wonder how we would feel :-(

  • Gmail User
    Gmail User4 ditë më parë

    Why the secrecy? Because it's scientific knowledge. Who knows what application it has?

  • LArKuLe
    LArKuLe5 ditë më parë

    Is there any relation to nuclear spin flipping?

  • ngc 5139

    ngc 5139

    4 ditë më parë


  • Ayush Tiwari ce20b022
    Ayush Tiwari ce20b0225 ditë më parë

    What can be more beautiful ❤️

  • Onkar Mane
    Onkar Mane5 ditë më parë

    Nothing is more fun than watching an American asking Russians why do they keep secrets 🤣 🤣

  • Nathan Samuel Unger
    Nathan Samuel Unger5 ditë më parë

    Thank you for helping me fall asleep

  • fran cis
    fran cis5 ditë më parë

    i watched this thinking i was smart enough to understand it. but im glad to know earth is stable 😂

  • John Barber

    John Barber

    5 ditë më parë

    I'm still going to strap myself to a big tree.

  • H G Malone
    H G Malone5 ditë më parë

    180,000 Million years ago - The Earth "Flipped": This caused the Continents to "Drift" and major weather changes: Now the Weather changes are causing the rotation of the Earth to alter: WE really need to study and track what is happening. You say we will not "Flip" again; What if our equator shift 5 degrees off the equator?! Could Alaska have a full year of "NO-SUN"? Or Antarctica A "Full Year of "NO Night".

  • ngc 5139

    ngc 5139

    4 ditë më parë

    No. Where do you get this silliness from?

  • TyBo Tesla
    TyBo Tesla5 ditë më parë

    The way he pronounces ‘centrifugal’ hurts my brain 😣😖🥴

  • Autofitment Centre
    Autofitment Centre5 ditë më parë

    Sitting here as a avid science follower and a technician it struck me that thread is not perfectly straight and can thus cause the imbalance described. Also when tossing the tennis racket or phone you are not doing it perfectly symetric. I would like to know what the result will be if the initial forces the caused the motion was symetrical? Also the construction needs to be perfect symmetry on a molecule scale So if the greatest moment of inertia does not flip what is the force need to overcome the stability of the orbit to destabilize it and if the smallest moment of inertia does not do it why?

  • Ritwik Shivam
    Ritwik Shivam5 ditë më parë

    11:15 that's how the minds of engineers would have rotated after reading that book as well, to understand "Engineering thermo"

  • burningruin666
    burningruin6665 ditë më parë

    Its stable untill we "screw" things up(on) it

  • Marius D
    Marius D6 ditë më parë

    How does this relate to the earths magnetic pole reversal which happens from time to time?

  • Michaels Musings
    Michaels Musings6 ditë më parë

    I think I’d like to be his neighbour great videos

  • Will Kadri
    Will Kadri6 ditë më parë

    me: trying to learn ads: sorry you lost focus, give me your money

  • Jake Hooton
    Jake Hooton6 ditë më parë

    Your a looser if you can’t perfectly flip your phone around. Probably gay to

  • Drew Andrews
    Drew Andrews6 ditë më parë

    Why aren’t there circles instead of squares at their large point masses? (6:54) / 14:48

  • D. Mac
    D. Mac6 ditë më parë

    the inicial force generated from first momentum - ( human force )- under 0 G's, would store that energy within itself, continuously bouncing the energy contact point around within itself.

  • Creative worx
    Creative worx6 ditë më parë

    Imagine education is like that at school.

  • masessum1
    masessum16 ditë më parë

    Too busy solving century old math problems? Don't we have Bitcoin computers to do that now?

  • Daryl15skydiver
    Daryl15skydiver6 ditë më parë

    Hello, first of all i've never been in any university or something, and i'm not graduate or degree holder, i'm just a guy who always think a lot and can do materials or particles displacement or mevement simulation in 3d for everything in my mind... I've Always have a particular intetest for physical science, and i'm autodidact... I may ne wrong in what i'm about to say or may be not. As you said, the earth can't just flip like this. But this phenomenon could be the reason why the Sun changes it's polarity sometimes, and the Sun doesn't change the polarity as often as the axis of rotation of the bolt because of the différence in the mass of the two bodies (billions and billions of Times and much more, and bigger mass implies bigger momentum)... The change in the magnetic polarity orientation of the Sun, which is much more massive than the planets in the system could lead to a change in the magnetic polarity of the planets too, as the mass of the Sun dominantes that of the planets, and this should be observed more closely, because if the mangetic polarity of our planet changes too much often, this could leave us without our magnetic field protection, and if meanwhile there are some Solar winds, we would be directly exposed to particles coming from the Sun... This us very dangerous...

  • Brendan Courage
    Brendan Courage6 ditë më parë

    @12:08 "The cylinder has no other ch- OPTION"

  • Luke Schoepke
    Luke Schoepke6 ditë më parë

    dont play with my emotions dude

  • Patrickmaydoe
    Patrickmaydoe6 ditë më parë

    i flipped my phone to turn it back over to the screen having a dude flipping his phone

  • re5o28
    re5o286 ditë më parë

    This might be a key to solving gimbal lock. Hmm.

  • kirtil5
    kirtil56 ditë më parë

    finally, now i know why this happens when i flip a notebook

  • Medication
    Medication7 ditë më parë

    Thanks for the cool explaination. I think about stuff like this and wonder how many different axis and forces and momentum are at play when you see those dirtbike guys flip their bikes. The gyro effect of the spinning wheels and parts in the engine/ reciprocating mass and whatnot.

  • Chad T
    Chad T7 ditë më parë

    2020 brough us pandemic and blm and free money. 2021 bring us hyperinflation and starvation? will he retract this video after the earth flips in 2022?

  • neonAnarchist
    neonAnarchist7 ditë më parë

    I knew about the tennis racket part. I’ve been learning to juggle, both balls and pins, but mostly pins. Whenever I have an object with a handle, like a tennis or badminton racket, I start juggling it. It’s pretty crazy, and this video is just so cool to me cuz I had no clue why it was happening

  • Bryant
    Bryant7 ditë më parë

    What if you could spin a person, would they more closely relate a tennis rackets or disc? I would imagine the moment of inertia diagram he showed would look more like a racket. How close does it have to be to work (me asking questions before I finish watching the video)

  • micahel hobbs
    micahel hobbs7 ditë më parë

    This is applicable to projectiles

  • AH Crafts
    AH Crafts7 ditë më parë


    JUSTFOR PIE7 ditë më parë

    so do you mean that the earth has already spined

  • Hydroxy moron
    Hydroxy moron7 ditë më parë

    Would someone help me understand something? I thought the water in the twirling bottle would slosh around in an irregular way, causing the bottle to do the second rotation thing. But, the explanation for the second rotation was that it was transferred energy. Does thus mean the water in the bottle is spinning in a uniform way?

  • Navid wahab
    Navid wahab8 ditë më parë

    Iam falling in love with you man, stop!

  • rkps987
    rkps9878 ditë më parë

    The goal of this video is to prove Prof Richard Feynman's claim wrong. Wow a bold statement. Wonderful video. I did learn something new.

  • La Vie Est basket
    La Vie Est basket8 ditë më parë

    Imagine writing that article and having it brought down so nonchalantly

  • B Emm
    B Emm8 ditë më parë

    Could this be why planets keep stable orbits?

  • Ahmad AlSubaie
    Ahmad AlSubaie8 ditë më parë

    [16:15] And He has cast into the earth firmly set mountains, lest it shift with you, and [made] rivers and roads, that you may be guided,

  • Machtyn
    Machtyn8 ditë më parë

    The crazy thing is, skateboarders, specifically, Rodney Mullen, intuitively knew this when he developed the "Impossible" skateboard trick back in the 1980s.

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