Seeking the unknown in the known (part 1, energy)

[Astrophysics]

A few years ago it came to my attention that everything somehow always related to energy. But the more I thought about it, the more I realized that I don't understand what energy actually is [o)]. There isn't a very good explanation of energy in my physics textbooks, only the basic stuff about energy. And my physics teacher sounds like she has never heard of the subject physics [:((] .

I'm hoping for some good explanations on energy (I say explanations and not explanation, because I think that there are more perspectives on this subject than just one).

[Tyger]

The concept of energy is classical, but when we convert it to a quantum mechanical concept we find that it is just the change of the phase of a quantum mechanical amplitude with time.That is what makes energy so important, it is related directly to how systems change with time. The quantum mechanical equation that describes the energy of a system is called the Hamiltonian, and it tells us how a system changes with time. If we want to make a system change with time we have to put some energy into it, which is why we heat a mixture of chemicals to make them react faster, etc..

That should give you some perspective on the true nature of energy.

[Astrophysics]

Thanks tyger, finally I'm learning some of the good stuff[6)]

Could you please recommend a book on this subject? I'd really appreciate it.

I thank you in advance,

Astrophysics