Why do positive and negative attract?

Question

All mass is attracted to each other due to gravity, which is really just a curvature of space time. But why do only postive and negative things attract. What actually causes the electromagnetic forces, specifically in a vacuum.

Answer 1

I asked my AP Physics teacher the exact same question one day, and he said, "I don't know, it's beyond my expertise."

I'll try to get back to you in a couple of minutes.

Answer 2

Positive and negative attract to get to a lower energy state.

The potential energy of a negative charge and a positive charge is

constant*(positive charge)*(negative charge)/(distance between them)

that equation is just from the definition of energy in a system of charges. So you can see that the potential energy is a negative quantity. Since distance is on the bottom of the equation you can see that if the distance gets smaller then the energy becomes a larger negative number, in other words, the system moves to a state of lower energy.

So the only reason things happen on their own is because it is going to a lower energy state.

Answer 3

I'll go out on a limb and say no one really knows.

Physicists will tell you it involves the exchange of photons, the force carrier particle associated with electromagnetic interactions at the quantum level, but I doubt they really know what that means.

So, what happens? Do like charges throw one flavor of photons at each other and unlike charges throw a different flavor? How does one flavor of photon cause charges to repel, and another to attract? How does that work? I don't have a clue, and I bet physicists don't either.

Answer 4

I don't see why you are willing to accept gravity so easily but not electromagnetism. You say, gravity is really just a curvature of space-time. I ask you - how does mass cause this curvature? Through a gravitational field, of course.

In the same way, charged bodies are surrounded by electromagnetic fields, which interact with electromagnetic fields given off by other charged bodies.

Of course, the reason why these bodies are charged at all is because they are composed of charged elementary particles. We may well define "electromagnetism" as the force mediated by photons which acts on these particles - of which there are a very limited number - rather than define charge as the property upon which electromagnetism acts.

If you are really interested, consider a career in theoretical physics... and make sure you campaign for the building of the VLHC in the second half of this century...