What if charges are not what they seem? What if rather than looking at electric fields separately, maybe charges are simply the aspect of the electromagnetic field that binds it in place, which is why the non-binding aspect of the field does not look like a sink or a source. That makes sense with seeing how electric fields and magnetic field values can vary according to the chosen inertial frame of reference; or in the other sense, for a specific inertial reference frame, the field values vary according to the flow of fields.

This is actually due to the fact that all thing are in constant motion, and their velocity only depends on the frame of reference. That is, if we choose a different reference frame, a charged particle was still in motion. The measured electric and magnetic fields may change around that region of space, but the electromagnetic field won't as it is a tensor describing the complete field state, regardless of the inertial frame of reference used.

Whenever the velocity changes, information about the change in fields simply travel outwards at the speed of light, which is not relative to the charge, but relative to the background. This is because the speed of light is simply the speed at which changes flow. For example, the speed of sound is the speed at which the disturbance in water propagates.

(So you see, information is not your grandpa's name. It simply is the flow of events reaching from one place to another.)

- [Doubt (SOLVED): How is light speed fixed, if all motion is relative? (Try reading: https://physics.stackexchange.com/questions/192891/if-all-motion-is-relative-how-does-light-have-a-finite-speed)) ]
- Answer: Speed of light is fixed, but it is fixed as the same for every observer. This is the result of the Michelson-Morley experiments, when they tried to find the speed of light against the background. So if the speed of light must be same for bodies moving at all velocities, it must mean that at higher velocities, the space must contract to create the same measurement. (The main answer in the link above explains this in terms of geometry better)

When does velocity ever change to begin with? When it's accelerated!

So acceleration is not just any kind of motion. It's just something that initiates motion itself! Or in other words, a force is what creates acceleration. Since mass and energy refer to the same concept, even a change in the fields is an acceleration generated due to a force.

If for a charge, if the electromagnetic field stays same around it
And if I change the frame of reference to one where it is moving, and observe a magnetic field
That, without any actual change in motion of the object, but only of my reference frames
Then isn't magnetic field just the velocity component of the electromagnetic field?

In other words, the magnitude of the magnetic field is proportional to the velocity of the charge.

Wild thoughts
So if I move myself, I see the charge as producing a field, although it is my eyes which are fooling me into thinking so
That is an ever-present illusion of the universe, right?

(Also refer back to the stackoverflow article I linked in the second Idea section)
(Also read the Idea section at the top)

If the field measurements are relative, then true, the only criteria would be that two bodies cannot move relative to one another faster than at the speed of light.

However, one of those bodies must also not move faster than the speed of light relative to a third body.

So the speed of light has to be references with respected to some stationary state. What we do know is that whatever it is, we can observe the relative velocity of light.

That is, we have measured the speed of light relative to Earth. But that may not be the velocity we observe if we are on another planet.

Am I wrong here? Did we really measure the true speed of light somehow?

What if, one body is moving relative to X at -0.7c and another at +0.7c? Won't they see the other body as moving away from them at 1.4c?

Answer: Yes, relative speed can be faster than c. But the apparent speed won't be. It will be according to the perceived spacetime contraction, which ends up being slower than c (0.9396c here). [Addition Rule: \(v_{rel}=\dfrac{v+u}{1-\dfrac{vu}{c^2}}\)]
- https://physics.stackexchange.com/a/165712/205108
- https://physics.stackexchange.com/a/356354/205108
- A third party's observation doesn't mean anything compared to each other's perspective towards one another (which is 0.9396c)
- The third party only saw the two bodies separately move at 0.7c in either directions, and he used that information to conclude their relative velocity was 1.4c
- This is kind of philosophical

Extra info: Though you can't add velocities just like that, you can add rapidities. Rapidity is the hyperbolic angle between two velocities in the Minkowski diagram.

If electrons and protons are chosen by convention, does it mean that it doesn't matter whether the electron is a sink or a source?

Both models should come to the same results then..
Or rather, the model is the same whichever pattern you consider.