Can You Make Magnets Orbit Each Other?

hey everyone today we're going to be seeing if it's possible to get two magnets to orbit each other in order to get one object to orbit another one you have to have two forces at play one of them needs to be an attractive force so you need something that's going to attract these two balls together and then you also need something that's going to repel them something that's pulling them apart and those have to perfectly balance out so that they keep each other at bay and so it can't move closer or further away it stays at the same distance from it so the way things work out in space where gravity is the dominating force gravity is the main force that attracts things together so what's the force that repels it well that's a centrifugal force so the centrifugal force comes from something spinning around in a circle if you spin around in a circle your arms fly out so the balancing act that keeps things in orbit is there has to be an attractive force and the thing that's orbiting around it has to be going fast enough so that the centrifugal force is pulling it away as it's being attracted towards the center and if you use gravity this works with any object with mass for example if i were far out in space and i took a bowling ball and then i shot a golf ball at the bowling ball i could get the golf ball to orbit the bowling ball but you have to shoot it at the right speed if you shoot it too fast then it has too much angular momentum and the centrifugal force is too high so it'll just go flying off into space if you shoot it too slow then the attractive force is stronger than the centrifugal force so it'll just fall into the bowling ball but if you shoot it at just the right speed then it will orbit around the bowling ball also because it's a bowling ball that hardly has any gravity we have to launch the golf ball at an extremely low velocity you can see it's only at point zero zero zero zero one eight ohm meters per second i've just sped up the time so that you can see it go fast with a force like gravity it's actually not hard to get things to orbit each other for example if i just start out with a bunch of golf balls randomly oriented in space and let's say these golf balls when they hit each other they stick together if i just let them fall in towards each other they'll eventually end up in some system that's orbiting each other so you can see eventually these golf balls start coalescing together and we get one big golf ball and eventually we get some smaller golf balls orbiting around the larger one and this is actually a stable orbit that stays there indefinitely if i speed up the time you can see that it stays there but the question is what about other forces besides gravity what about magnets have you ever wondered if you took one spherical magnet and another spherical magnet and threw them towards each other could you get them to orbit around each other as long as there was no friction let's say we were out in space could they just orbit around each other indefinitely well first since we can't go out to space to do this let's just try this on a very low friction surface and see that if i throw one magnet towards the other i can kind of get them to spin around and orbit each other let's try it out and see what happens okay let's see if i can get this to work i'm just going to set one here and then i'm gonna throw the other one at it and see if it has enough centrifugal force as it goes by that they'll just kind of orbit around each other [Music] whoa look at that spin [Music] holy cow as this ball came at it and came closer it kept its angular momentum so the whole system had to spin in a circle like this and it was spinning extremely fast you could hear it but that's not really defined as orbiting in order to orbit they'd have to stay apart from each other and kind of move around each other like this so what they really did was come together and then spin really fast in a circle so by throwing two magnets at each other i wasn't able to get them to orbit each other now the reason this isn't working is because magnets are a dipole as opposed to a gravitational field like a gravitational body which is a monopole which means that the field extends out in all directions equally but for a dipole like magnets the magnetic field looks like this so if you try to orbit around it you can see that you're passing through different strengths of magnetic fields pointing in different directions so the magnetic field changes depending on where you are around it but if we do this a little smarter we might be able to get some type of orbiting effect with magnets first of all instead of having two bodies that are about the same size we're going to have one more massive body and then another smaller thing orbiting around it and we're going to stay in the region of the magnetic field which is similar for example the magnetic field of these cylindrical magnets is going to look like this so it's going to come up from top and go around the bottom but if you'll notice that right around the center it's actually pretty consistent so if we can get something to orbit right around the center of the cylinder here it should be able to stay in the same range of magnetic field so it's not changing as it goes around it what i have here is a magnet on a thin rod and i'm going to start it off with some velocity around it so i'm going to move it around in a circle like this and let's see if i stop moving it if it will continue to orbit around it so you can see that when it's pointed in this direction it's attracted to it so this is an attractive force so now let's try to wiggle it around it and now i'll stop wiggling whoa it actually orbited around it you're probably thinking that this is the same motion it would have if i just wiggled a rod with a weight on the end of it normally but actually you can kind of see how it gains some momentum as it comes closer to the magnet and spins around as if it's starting to enter into an orbit [Music] this is actually a pretty cool setup if you manipulate it just right you can actually get a magnet that semi-orbits around a center magnetic mass no matter how good i get it started orbiting around it always seems to spiral towards the center there's two main reasons that this could be happening the first reason is is that because the rod that it's on is bending around that takes some energy and so there's continually energy lost from the system so it starts out further away and it loses more and more energy and spirals towards the center but what if we had a completely frictionless rod would it still be able to orbit around and never stop well the answer is still probably no the reason is because let's take for example gravity which we know can produce stable orbits we know that the gravitational field scales by one over r squared so the strength of the gravitational field drops off by the squared value the further you are away from it this is actually the same for the electric field as well in the bohr's model of the atom you have electrons orbiting around a positive nucleus now it doesn't actually look like this for electrons and protons because electrons are so small so you can't actually define their position and velocity at the same time so you have to describe more of a wave function for them but even in a waveform the electrons still have an orbital momentum around the center of the nucleus so we know that the electric force can cause things to orbit around each other the gravitational force can cause things to orbit around each other and a similarity between these two forces is that they both scale by one over r squared it turns out if you deviate from one over r squared just a little bit it changes the stability of the orbits a lot for example in this graphic the black ball has a force that scales by one over r squared the purple one is 1 over r to the 1.9 and the orange one is 1 over r to the 2.1 so a force that scales by 1 over r squared can produce stable closed orbits by stable it means that they'll stay in orbit forever and closed means that they stay in the same path but the problem is for forces that scale by one over r cubed like the magnetic force you can't produce a stable orbit so the answer is no you can't get magnets to stably orbit around each other even if you were out in space because they're dipoles and because the magnetic field drops off by one over r cubed and thanks for watching another episode of the action lab i hope you enjoyed it if you did don't forget to subscribe if you haven't yet and also hit the bell to be notified when i release my latest video and thanks for watching and i'll see you next time

Channel: The Action Lab

Views: 1,213,825

Keywords: Magnetic orbits, magnets orbiting, the action lab, magnetic field

Id: d2-EqVdaNT4

Length: 8min 45sec (525 seconds)

Published: Sun May 09 2021