# Can a Magnetically Held Sphere Levitate in the Air [closed]

I have a Sphere like device in my book that floats around doing whatever stuff it does. But I wanted a different implementation than your typical thrusters for it to levitate.

So, I designed two layers of magnets in its core, both opposite poles are facing each other so when there is a strong power current flowing through the magnets they start pulling away from each other that (in theory) keeps it forever levitating in the air. The idea is that the force that pulls the magnets away when contained in a shell and control the power current in the layers to make it stable. The top layer pulls and the mid layer stabilizers. With a control guidance system installed it doesn't fly off in one direction. You don't need to focus on the power supply (it's sci-fi) and the area that it patrols contains no metals. (I probably don't need to point this out but, this is not a magic question I want scientifically sound facts.

So my Question is this: Would a magnetically held sphere levitate in the air?

Would love to find out if this is possibility and use the facts for my book. And as always if you want any more details don't hesitate to ask.

• Could you perhaps try to explain how you think it would work yourself? In order to levitate, you need to generate a force that counteracts e.g. gravity, right? Where does that force come from? Also, what happens if you push the sphere closer towards Earth? What happens if there is wind? Perhaps you should describe your design a bit better May 29, 2018 at 8:41
• This sounds like a misconception that magnetic fields and gravitational fields are linked, which they are not. May 29, 2018 at 9:04
• @StephenG i don't think that they are linked. what i was trying to do is have the magnetic fields fight each-other in a controlled heavily power environment that pushers away from gravitational pull more then gravity can pull it back May 29, 2018 at 9:27
• Equal and opposite force must occur between the two magnets. One will push and one will pull but the net force on the assembly (from the magnets) will be zero. This is Newton's third law. May 29, 2018 at 9:33
• I don't see where does the net force come from. A system of material points can be accelerated only by an external force; what happens inside the system does not count. The forces between internal components of the system do not count -- in order to accelerate the entire sphere you must have an external force. May 29, 2018 at 9:56

I guess that the magnetic sphere you designed can't work respecting the magnetic laws we know so far, but i do admit that i don't in my mind have a clear view of your device. Anyway, I'll try to answer your question, which is

Would a Magnetically Held Sphere Levitate in the Air?

maybe this will help you to clarify how this could be obtained.

First of all: how the magnetic force, and every other force, work. As other people stated, there's no link between gravity and magnetic field, therefore whatever system you'll design will need to apply some "magnetic force" to the earth and not to the system itself. Otherwise it's like to pretend to lift yourself, standing in a bucket, trying only to pull the handle: it simply doesn't make sense. It's not very scientific, but luckily the earth has his own magnetic field, and you can somehow (it's sci-fi, after all) interact with this field. Or, you can pretend to apply your very-powerful-and-spectacularly-controllable magnetic force to the metals inside earth. As far as I know every material loses its magnetization above a certain temperature (Curie temperature), and I fear that could be an issue with the Earth internal temperature. Anyway, still sci-fi, therefore some licenses could be taken.

Second: you need to control the "magnetic forces". As per the Earnshaw's theorem, you can't have a stable static configuration. Said that, you can pretend to have a very complex system or use some help from other physical phenomenon. Let's define that we - somehow - can have a device that can properly interact with the Earth magnetic field and that he can provide lift. You could use four of them and create a device that could resemble a quacopter. Or, you can use the levitron principle: spin-stabilized magnetic levitation. In this case your sphere needs only to rotate fast enough to have stability, and your "magnetic motor" needs only to modulate its power to gain or lose height.

To summarize: yes, a "magnetic" sphere can levitate in the air, but not in the way you supposed.

I didn't discuss about how to actually move the sphere forward or how to curve its trajectory because this can be done in a lot of different ways and i don't know how your world could/should apply for that. Maybe a gigantic magnetically levitating zeppelin (which has propellers to move) could fit perfectly or not, you know.

• I don't see how. You only stated "yes it can because sci-fi". But that's not a reality check answer.
– L.Dutch
May 29, 2018 at 14:45
• How does inability to have a stable static configuration apply to something that is specifically supposed to move? In this case you want controlled instability not static stability. May 29, 2018 at 15:00
• Actually i explained why the original contraption doesn't make sense at all, then i suggested a couple of concepts about how a sphere can levitate: it could use the levitron concept and one (big) electromagnet inside the sphere. The sci-fi part of the answer is here because the two suggested solution (earth magnetic field and/or earth internal metals) could be useful to describe a "possible" way to have proper application point for the generated magnetic force. And it's called sci-fi because no one ever build a flying vehichle shaped as a sphere and lifted by magnetism. :) May 29, 2018 at 15:07
• @Ville Niemi: you are right, the theorem was my hint (for me) to think about the electromagnets configuration. A fastly rotating, self balancing, sphere is way more interesting that a "magnetic quadcopter" covered by a sphere. But in the end is true, no static stability is required. May 29, 2018 at 15:15

I don't see how this can work. If I have understood your design concept, you put two magnets (or magnet cores) close-by in the same assembly.

They will either attract or repel each other, but in neither of the two cases they will counter the gravitational force acting on the assembly. Your device will simply fall on the ground. Don't forget that the resulting of all the internal forces acting on a body is null: you can't lift yourself by pulling up your ponytail!

If you want magnetic levitation, one of the two magnets has to be outside the assembly and must generate a force on the assembly so that it can oppose the gravity.

• That last sentence : note the force is between the two magnets. May 29, 2018 at 9:03
• @StephenG, got it. check now
– L.Dutch
May 29, 2018 at 9:28
• you can't move a sail ship by blowing the sails while being on the same ship: of course you can, you just need a powerful enough fan! The boat is free to move, and there's no net horizontal force on it. A better example would be the famous "Pull yourself up by your bootstraps". Doesn't work if you're wearing the boots in question. May 29, 2018 at 10:23
• @nzaman, changed to a literary quote...
– L.Dutch
May 29, 2018 at 10:26
• @KamiKaze youtube.com/watch?v=uKXMTzMQWjo Mythbusters did it. Of course you'd be better off pointing the fan backwards and not have a sail but it does apparently work. They speculate on how it works at the end of the video. May 29, 2018 at 15:05

If you're writing about a large, mostly empty, magnetic sphere, which in its interior holds a smaller and also magnetic sphere, then yes, the small sphere could in principle float in the magnetic field containing it. It would immediately try to rotate and move from the center of the field in order to be attracted to one of the inner walls, but if the outer magnet is an electromagnet, this in can be avoided using the same principle as ion traps i.e. rapidly oscillating fields.

If what you mean is two spherical magnets (shell+core or of whatever shape), both of them floating away from a non-magnetic ground, despite gravity because of the magnetic interactions between each other (citing from your comment):

both magnets are in the same shell. the magnetic poles fight each-other in a controlled heavily power environment that pushers away from gravitational pull

then no, this does not work that way. Making two bodies repel each other strongly does not make them pull against Earth's attraction. This is independent of their force of magnetic repulsion (from each other). So the answer to the question would be no. You'd have to think of a different mechanism for your floating sphere, if you want it to be scientifically sound.

• both magnets are in the same shell. the magnetic poles fight each-other in a controlled heavily power environment that pushers away from gravitational pull May 29, 2018 at 9:35

So my Question is this: Would a Magnetically Held Sphere Levitate in the Air

No. The force acts between the two powerful magnets, so even when one of them is pushed upwards, the other is pushed downwards, and it "falls" faster.

The same would happen if you sat outside your car and pushed against the steering wheel: the car would move forward, and momentum would be transferred to the ground by your feet. But if you sat inside the car, the momentum would get transferred from the steering wheel to the seat, and the car would not move at all. You need to exert force on something outside the sphere

But you can achieve a similar effect using Meissner-Abrikosov grapnels, thin layers of unobtainium (or similar) that can be flipped between a normal state (temperature above, say, 80 K) and type-II superconducting state (temperature below 80 K). When active, a MAG will undergo an effect called flux pinning or quantum locking, and become fixed in space with respect to a magnetic field (such as Earth's). Having several MAGs, half of which in inert state and free to move, while the rest are active and locked in place, allows the sphere to "float": within the sphere, the free MAGs are moved to a new position in the direction where the sphere needs to go. When they are, they're cooled from 90 to 70 K, and thus become locked in place, while the heat is transferred to the other MAGs, that warm up, cease to be superconducting, and unlock.

This is something like how a person walks - by moving a foot in the right direction, pushing it down to lock it on the sidewalk, then moving the other. Your sphere can do the same in space using two sets of MAGs.

Of course, the strength of the grasp depends solely on the external magnetic field, which isn't all that great. But if the sphere is light enough (let's suppose it's full of lots of vacuum), the combined buoyancy from the Earth's atmosphere and its space-locking properties could be enough to get it to hover, apparently, "reactionlessly".

The method you suggested can't work. You are pushing the sphere up with the same force that you are pushing it down, so the net force on the sphere is 0. It will still fall.

You could hand wave your contraption if somehow the bottom magnet is not attached to the spaceship. For example it is attached directly to the universe or some other fixed point that is not part of the spaceship but moves with it. So the downward force would be pushing against that instead.

It follows that if you can hand wave that, that you would then also have the sphere's means of propulsion through space. It would be by using the same magnet technology to create thrust. This is because when the thrust is no longer countered by gravity, it would result in movement.

Your proposed mechanism of 2 magnets pushing against gravity will not work as has been pointed out by other answers. But with a sci-fi strength magnet, you could assert that your ball floats using diamagnetic levitation.

http://www.physics.ucla.edu/marty/diamag/

Many common materials such as water, wood, plants, animals, diamonds, fingers, etc. are usually considered to be non-magnetic but in fact, they are very weakly diamagnetic. Diamagnets repel, and are repelled by a strong magnetic field. The electrons in a diamagnetic material rearrange their orbits slightly creating small persistent currents which oppose the external magnetic field. Two of the strongest diamagnetic materials are graphite and bismuth.

The forces created by diamagnetism are extremely weak, millions of times smaller than the forces between magnets and such common ferromagnetic materials as iron. However, in certain carefully arranged situations, the influence of diamagnetic materials can produce startling effects such as levitation.

It was proved in 1842 that it is impossible to stably levitate any static array of magnets by any arrangement of fixed magnets and gravity. However, the addition of diamagnetic materials makes such levitation possible. The July 22 Nature paper, Magnetic Levitation at your fingertips, describes two configurations where diamagnetic materials are used to stabilize the levitation of a magnet in the field of a fixed lifting magnet.

This is the prinicple behind the famous magnetically levitating frog. I thought this magnet hovering between fingers was also cool. Your sphere can alter the strength of its magnetic field and so levitate by diamagnetic levitation - provided it has the right substrate below it!

Linked below is the first in a video series in which the author systematically tests every element he can get his hands on for diamagnetism, paramagnetism and ferromagnetism. I learned a lot. Ice can be pushed with a magnet? https://www.youtube.com/watch?v=62dez4tD5Ok&t=144s