True, and you can magnetize a needle (temporarily) by simply rubbing it against a magnet a few times. All kinds of ferrous metal can become incidentally and temporarily magnetized in various common ways. If you put a magnetic compass near a screwdriver or pair scissors you have around the house, it will probably deflect the needle. Also, microwave ovens have powerful magnets and if you wear a mechanical wristwatch, it will become magnetized if you wear it nearby. When a mechanical watch becomes magnetized, its timekeeping accuracy suffers until it is demagnetized. You can demagnetize common objects with a basic tape deck demagnetizer wand (which those over a certain age will remember).
People who navigate with map and compass already know this, but the Earth’s magnetic field moves around and is not aligned to the geographic N and S poles. You have to account for this difference between magnetic north and geographic north when using a paper map to navigate. It’s because the solid inner core moves within the liquid outer core that the magnetic field is able to shift.
Light waves are more than just "related" to radio waves. Light waves and radio waves are both the same thing - electromagnetic radiation. The only difference is the frequency at which they oscillate. To make an analogy to sound, if radio waves are "bass", then light waves are "treble".
Back in college I remember a little book by Max Born. The preface had a paragraph about this. Sadly I don't have the book anymore but I remember it as this. His take on particle/wave duality was that probably neither really exists, they are only useful concepts that we create. Put differently: the universe is made up of stuff. But we can't perceive the stuff directly as it really is. Every form of perception we use involves more stuff, which interacts with the stuff being perceived. What we perceive is not the stuff itself, but the interaction between the stuff we used to perceive it, and the stuff being perceived. That interaction appears or behaves as either wave or particle.
It travels at the speed of light. Gravity waves have been detected, and they travel at the speed of light.
What? You joined for this?
radio waves on this side of visible (ROYGBIV) followed by X then gamma on this side. All the same sort of "stuff" and put into use by all of us daily: remote on your garage door opener: radio, remote on your TV controller: infrared.
If you get down to it, nothing has any direct link. All forces are exerted over some distance in space, call them "fields". Even the coffee cup resting on my desk isn't actually touching the desk. By that I mean the atoms are never in contact, but are separated from each other. They are very close to each other. Close enough for the closest atoms of the desk and of the coffee cup to exert forces against each other over that tiny distance. Intuitively the terms "touch" or "in contact" don't mean what we think, but instead they mean close enough for these local forces to take effect.
The answer is that the force, like gravity, is inversely proportional to the square of distance. That means small changes in distance make big changes in the strength of the force. It's easier if you don't pull directly against the magnetic field, but perpendicular to it - slide them against each other until they are offset which weakens the magnetic attraction.
