I know the definitions for energy, yet I still find them unsatisfactory. Energy seems to be something which both exists and does not exist at the same time, so really, how would you quantify it? It's like that old saying, "You can't see the wind, you can only see where the wind has been." Does energy operate the same way; can we not percieve it, only its effects?

You physically perceive energy at all times. Everything that you can see, hear, and touch is energy. It just whether its potential energy or kinetic. It takes energy to make absolutely everything, every atom in your body, and every atom in existence is energy.

I get that. But what perplexes me is how something can exist without being of matter. It feels like something from nothing, even though I know it's not. I accept the current definitions out of faith and convenience, but our understanding of the "substance" of energy is almost none.

Light has mass.

Or, E=MC^2 aka energy equals mass times the speed of light squared.

Theres the answer!

How can anything exist if there is no energy behind it Homer? What are you referring to?

Where did the energy come from? It can not be created or destroyed, yet it is here.

Does electo-magnetic radiation have mass, and not just light? Does the force of gravity have mass? Does heat? If these things do, then wouldn't it be concievable to turn energy (a lot of energy) into matter and the other way around? It seems that we only know that these things exist, but not much else about them.

I know that it is impossible for something to come from nothing, but it seems as if energy, and forces, especially forces, exist AS nothing.

Maybe string theory is the answer and we're all just little vibrating loops of energy, and matter is not important.

Energy is a little town in Texas, about half way between Hamilton and Commanche.

Does electo-magnetic radiation have mass, and not just light? Does the force of gravity have mass? Does heat? If these things do, then wouldn't it be concievable to turn energy (a lot of energy) into matter and the other way around? It seems that we only know that these things exist, but not much else about them.

I know that it is impossible for something to come from nothing, but it seems as if energy, and forces, especially forces, exist AS nothing.

Maybe string theory is the answer and we're all just little vibrating loops of energy, and matter is not important.

We already know how to turn matter into energy although in an uncontrolled manner. That is the source of the energy in nuclear weapons, and also in the sun and all the other stars.

Particles of all sorts exist as both matter and energy, and which properties they exhibit depends on how you observe them.

An interesting experiment first performed in the 1950's reveals some of the fundamentally paradoxical effects of quantum mechanics. If you take a single photon and split it with a beam splitter into two seperate equal length paths that converge, you can record with a photographic plate the interference pattern as it interferes with itself. If you use a particle detector, the particle properties can be detected on only one path, with an equal chance it will be either path. The wave properties take both paths at once, while the particle properties take either path equally probably. Which it is doing is not determined until the observation is made.

Particles have specific energy, while waves can vary infinitely. If a wave has an energy that does not match any of the limited number of particles, when it is turned into matter it will turn into several particles whose energies add up to the original energy of the wave. This is the principal used in detecting the production of particles in particle accelerators, by observing the cascades of particles the original particle produces as it decays.

Does electo-magnetic radiation have mass, and not just light? Does the force of gravity have mass? Does heat? If these things do, then wouldn't it be concievable to turn energy (a lot of energy) into matter and the other way around? It seems that we only know that these things exist, but not much else about them.

I know that it is impossible for something to come from nothing, but it seems as if energy, and forces, especially forces, exist AS nothing.

Maybe string theory is the answer and we're all just little vibrating loops of energy, and matter is not important.

Those things you mentioned do not happen unless something causes it to happen, and when that force, whatever it may be, does make one of those things happen you could say it has mass because there are, at least, subatomic particles involved. I guess you could say things like heat, light, and gravity exist as nothing until the requirements are met for their existence.

As for string theory, I doubt it, lol.