Fundamentally, what is an electric field?

SystemTheory

Interference patterns exist in EM fields. The classic example of particle-wave duality is light (or electrons) passing through a double-slit.

http://en.wikipedia.org/wiki/Double-slit_experiment

I'm not sure how this applies to gravity or electrostatic field models. I'll think about your question re. the moon interfering with the Sun's gravitation on the earth ...

SystemTheory

The OP asks about the similarities between General Relativity and Electromagnetic waves, so I'm posting this link, which has a number of (apparently informed) papers near the bottom on Gravity and Relativity:

http://www.metaresearch.org/home.asp

I've always wondered how space instantaneously "knows" how to bend the instant I drop some mass into a region? In other words, Newton's view of gravity is instantaneous and I'm not sure how Relativity impacts this assumption, but admittedly, I've never thought much about it.

Longstreet

Well, energy/momentum is something, or represents the effect of something. And whatever that something is everything is made of it.

My interpretation/speculation (and that is all it is) is that "something" is structures in space-time. Or, in another way, alterations to space-time. We see that plainly in gravity as space-time has a structure causing gravity. By loose induction, all physical phenomena, including EM fields, would be different types of structures of space-time. Now, I think string theorist attempt to actually codify this but I don't know much about it. It would have to be a structure which impacts each type of particle differently, where as GR impacts everything the same.

Phrak

These guys proposed that the electric field potential could be elements of the metric for 5 dimensional spacetime.

dE_logics

All 'normal' matter (to be precise) is made up of charged and uncharged particles.

An electric filed which exists in space simply has this property to apply force on these charged particles.

sridhar10chitta

Two important properties are 1. The electric field due to a charge fills the entire universe and 2. The electric field penetrates through matter.....In short, where there is a charge there is an electric field around it.

dE_logics

I'm afraid point 1 is violating quantum physics and so that actually does not happen; but cause I'm not into that subject, I can't explain further.

Longstreet

How does that violate quantum physics? You are saying at some large distance from a source you would no longer be able to make a measurement of the electric field?

qsa

I am responding a little bit late, but late is better than never. Well, the reason that nobody has answered you question what is "charge" is that there is no such a thing. Even in QFT the potential is put in there by hand. My idea is that the so called charge (effect) is only due to interacting particle based on the mass. for example the proton pulls on the electron wavefunction toward itself (as per the interaction for high potential particle-equivelent to high mass- in my website), the potential is automatically is introduced inthe system. If the particles waves are of comparable size then the waves of the particles facing each other get exponentially chupped of in front of each other forcing the wave to back off ie. repultion. That is why I think QM and GR are not fundemental but manage to describe processes very accuratly. I hope my system does that and more.

http://www.qsa.netne.net