For example I am wondering, in the following thought experiment: If you have a single atom resting in a vacum and it is hit by a photon, causing it to heat, what is the reason for the resulting motion of the atom? i.e. what intrinsic changes occour in a single atom when heat is applied.

Rocket launchpads are often sited near the equator to use the earth’s rotation to save fuel. Are there any other examples of mankind using this tremendous source of energy?

A mass of air will travel from an area of high pressure to low pressure whether or not there is a wind farm in the way.....where would the energy extracted by the wind farm otherwise exist. Is it theoretically possible to alter the energy balance if a wind farm were vast enough.

Basically, would it be possible to base some electrical or other type of machinery or technology on the transfer of different types of energy through a vacuum such as heat through radiation or light?

Is there any technology which uses this at the moment, but with an actual vacuum as compared to fibre optics or something?

Surely to the extent where you wouldn't necessarily have to pump the gas out to create a vacuum surely this would be cheaper than using actual materials?

Anyway just a thought, any answers would be appreciated.

Human beings have identified four fundamental forces of nature (the strong nuclear force, the weak nuclear force, the electromagnetic force, and gravity), and it appears that these four fundamental forces enable us to account for everything we observe in the universe (including all matter – i.e. all particles and subatomic particles are understood to be stable manifestations of these four fundamental forces). It appears that all other forces observed in nature can be derived from these four fundamental forces.

If it is correct that Energy is defined not by what it is but by what it can do, then is it correct to assume that energy must be some measure of the fundamental forces of nature acting upon one another?

The fact that mass (such as matter) can be converted into energy (such as in a nuclear explosion) in accordance with Einstein’s equation suggests that everything we observe in the universe is simply the various stable manifestations of the four fundamental forces acting upon one another. If this is correct, then what is a force, exactly (i.e. what is a force, not what does it do)?

According to the second law of thermodynamics, the energy of a closed system always tends towards equilibrium (because an equilibrium state has a higher probability than any other) and the overall entropy always increases. Can energy (all forms including heat, potential energy, kinetic energy, chemical energy etc.) be explained and defined by the fundamental forces of nature tending towards equilibrium?

According to Einstein's famous equation E = MC2, or Energy = Mass times the speed of light times the speed of light. This tells us that anything that has mass, such as matter, is comprised entirely of energy. Any physical object with mass is therefore simply a lump of energy existing in some stable form.

As I understand it, all forms of energy, including chemical energy, kinetic energy and potential energy are covered by Einstein's equation, meaning that fundamentally all forms of energy are the same basic 'stuff' (for want of a better word). My question is, therefore, what exactly is energy? I want to get to a fundamental understanding of energy, because it seems that such an understanding would help to explain much of reality.

I'm not asking for explanations about work done etc, I'm asking at the fundamental level what is energy?