It is well known that energy cannot be conceived from nothing , nor disappear.
my question is this: if energy changes from one form to another I'd guess the total amount of
energy in all that exists is zero. I was told that this is not true, the number is very close
to zero but it is not zero, Why? Where does that small amount of energy come from?
You enter into a very difficult area because it is very difficult to define what "energy" IS.
We know numerous formulas for HOW ENERGY BEHAVES but that is very different from what energy
IS. If you page through Richard Feynman's three volumes on Physics, you will find that he
concludes that no one knows what energy IS, only how it behaves. All the conservation laws
involve HOW energy behaves not what it IS. In fact on scales smaller than the Heisenberg
Uncertainty Principle energy is not even conserved. It can be "borrowed" for a very short
time -- less than Plank's constant divided by the amount of energy "borrowed". This gives
rise to virtual particles and other very esoteric ideas. So it is not entirely true that
energy cannot be created from "nothing", just not for very long!!!
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Update: June 2012