Author Options:

magnet gravity Answered

Couldn't, with well position magnets, create an orbit around a central magnet? Almost like perpetual motion? I've been playing around with magnets lately, and I've gotten magnets to do 2 full revolutions around other magnets before coliding. Is it possible?


You probably could, but the orbit will still decay, and trying to generate power from the orbit would likely destroy it, also, this would be extremely difficult to do on Earth, or anywhere with gravity, because gravity would most likely be stronger than the magnet.

Hey, Guy, are you still interested in this? It's 2-1/2 years old, and started getting bumped this past June. I can tell you that in general the answer is no.

You can work it out either using forces or potentials, but it turns out that only 1/r2 forces (1/r potentials) like gravity and electric charges, have stable elliptical orbits. The latter are a prerequisite for stable circular orbits, because a small perturbation from circular becomes elliptical.

Dipole magnets have a 1/r3 force law in the equatorial plane, and a more complicated structure around the poles. The consequence is that any small deviation from circular is unstable, and the magnets either crash into each other or fly apart.

As Betelgeus3 wrote, you would need to use electromagnets, at least for the central part, with an active feedback system to constant adjust the current to "deperturb" the orbit. The "Galileo Gravitator" executive toy uses this kind of system to suspend a spinning ball in the air, and Steveastrouk recently posted (no I don't remember where!) a nice circuit to do the feedback.

yes, but there would need to be a monitoring system that could constantly adjust the central's power to keep the others up for as long as possible. Realistically, there's too much interference for something that precise to work on a homemade budget.

With the right orientations, it would be possible... the problem being that there's no such thing as a perpetual orbit. Any object that orbits around another is "falling" toward the central object, it just happens very slowly because it has enough lateral momentum to travel in a spiral that eventually results in either a collision or "escape" of the orbiting object. When you got the magnets to make two revolutions, you made the same kind of spiral, but the magnets were too strong compared to their momentum, so the "gravity" overcame the lateral momentum. A heavier orbit magnet or a weaker central magnet would make the orbit last longer. It would be incredibly difficult to actually set up a working orbital system like this because and orbit is a very delicate phenomena. Small changes make a lot of difference. Neat idea though... if you get it to work, put up an 'ible.


8 years ago

How did you do this anyway?

It should be, if only for a limited time. It would depend on a constantly held field of magnetism or eventually the orbit would decay. It is fairly easy to make a static "suspension" of a magnet or magnetic item. With movement involved, the mathematics get a little beyond me though :-)