# The role of magnetism in gravity [closed]

Ok, I haven't done any experiment and please don't get all technical "what type of scales are used"

But here is my question

Does the weight of and electromagnet change when it on?

Here is my though! If you place an electronic magnet on a weighing scale and weighed it. Would the weight change when you turned it on.

Would the magnetic field generated by the electromagnet attract or repel against the earth magnetic field changing its weight in a Positive or Negative direction

What's your thoughts. Dose magnatisum play a role in gravity?

• That would be nice. Don't you think that we would already levitating with our cars instead using tires? Commented Mar 6, 2017 at 20:35
• What does this have to do with electrical design? Seems more like a physics question to me, if you want to phrase the question as electrical noise then edit it, as it stands its off topic. Please read the help center on how to write good questions. Commented Mar 6, 2017 at 20:37
• I'm voting to close this question as off-topic because it's a physics question. Commented Mar 6, 2017 at 20:44
• Not only does energising a magnet have no effect on its weight, but also peanut butter has no effect on the rotation of the earth Commented Mar 6, 2017 at 21:25
• @MarcusMüller Well it should be moved to physics.SE, then, not closed. Commented Mar 7, 2017 at 1:38

The weight of the electromagnet is only a function of its mass and the pull of gravity. This has nothing to do with magnetism.

However, the total force between the earth and the electromagnet can change when the magnet is turned on. This is because the earth produces its own magnetic field. The two magnetic objects will have magnetic forces between them, depending on alignment. This force on the electromagnet due to it interacting with the earth's magnetic field is in addition to, and independent of, the force between the magnet and the earth due to gravity (the magnet's weight).

Does the weight of and electromagnet change when it on?

Yes, the weight of an electromagnet changes when it is energized (but only by an extremely small amount).

When you put current through an electromagnet to turn it on, you are storing energy in its magnetic field.

As you probably know, all mass produces a gravitational field around it. Energy also produces a gravitational field. This includes the energy stored in the solenoid (or stored in a capacitor, etc.) So increasing the energy increases the gravitational field around the magnet, which increases its weight in Earth's gravity.

As I said, though, it's an extremely small amount. The effective increase in mass is determined by the formula $e=mc^2$. Even the 340 MJ of energy stored in a big MRI magnet only weighs 4 micrograms. I think the forces due to the magnetic field itself would completely swamp any attempt to measure it.

Here's a paper proposing to use this effect to produce man-made gravitational waves (though I would think a giant centrifuge would be cheaper).

(Note that the mass of the solenoid does not change when current is going through it, since the total number of electrons stays the same, whether they are moving or not.)

The MASS of an electromagnet does not change when it is energized. There is, as far as my understanding of physics knows, no relationship between magnetism and gravity.

I can imagine that an experiment could be constructed where the apparent weight of the electromagnet changes, based on interaction with the Earth's magnetic field, or objects in its environment.

• very strictly speaking, energizing anything does change it's mass – on a relativistic scale. So, totally irrelevant for anything on earth. Commented Mar 6, 2017 at 20:44
• I could be mistaken, but is not the increased dissipation going to shed that relativistic mass?.... Ahh ... but the I**2-L energy storage ... yeah ... that'll change EVERYTHING :) Commented Mar 6, 2017 at 20:53
• Energy is what is equivalent to mass, not energy flow - for example, if you have a coil core that is highly charged with magnetic energy, it will be "massier". The fact that it got warm and radiates heat doesn't matter, if the energy to heat the thing up came from "outside". Commented Mar 6, 2017 at 20:54
• I got it ... I'm just riffin' on the theme. (Which is why I mentioned the I**2 * L ... ) Commented Mar 6, 2017 at 21:08

Hah, Shameless plug. You can measure the magnetic force on "something" and determine it's magnetic susceptibility. So we are weighing a magnet and the seeing how the weight changes when magnetic material is brought near.
http://www.teachspin.com/foundational-magnetic-susceptibility.html