and by substantial distance i mean like a square mile.
i know its possible, but what would the "scale" of a magnet like this be? and what would, theoretically, be the scale of a man made magnet (electromagnet/ or other) that could like... cover the whole world (if its possible)

With enough materials, you can make an electromagnet as big and powerful as you want. I'm not sure of the math behind how they scale up, but yes.

A square mile isnt a substantial distance. It isnt a distance at all. A square mile could be a substantial area.

why thank you, now everything makes sense

cover the whole world (if its possible)

Think about the fact that it takes the entire core of the earth spinning however fast it spins (fast) to magnetize the world just enough to make compasses point north. Then think of a way to top that.

im pretty sure the core of the earth doesn't spin, but even if it does it wouldn't do shit to make the earth magnetic.

the core of the earth does rotate, and current theory suggests that this sustains the magnetic field (look up the dynamo theory). if some magnetic materials are present, and conductive material such as molten iron is rotating, a current is induced which in turn can magnify the magnetic field.


in response to the original question, let's say for simplicity's sake that you want to disrupt all compasses within a mile of a certain point - a circle of radius 1 mile. If you have a wire going straight into the ground and extending up into space, very far both ways, and if you assume the earth's magnetic field is .5 gauss, the wire would need to carry a current of at least 402,336 amps.

i wouldnt think the core of the earth makes it magnetic, because its past its curie point, but hey, im talking out of my ass

anyway, the power of a magnetic field decreases at a really fast rate as you get further from it, so you will need a lot of energy to run it. of course its theoretically possible. as for a permanent magnet, im guessing it will have to be really big

anyway, the power of a magnetic field decreases at a really fast rate as you get further from it, so you will need a lot of energy to run it. of course its theoretically possible. as for a permanent magnet, im guessing it will have to be really big

For the above example the strength of the magnetic field would be inversely proportional to the distance from the wire.