# Basics of energy

I am not able to understand the second paragraph well. Please elaborate me anybody

• Please be more specific on the sentence or sentences that you can't interpret. – David White Jan 26 at 6:24

The second paragraph tells us about how abstract the concept of energy is but also how naturally connected it is to the universe. The author is trying to convey that energy is some sort of a number that one can calculate using certain formulas (like $$\frac 12 mv^2$$ for Kinetic energy or $$mgh$$ for Gravitational Potential energy) for objects in the universe, and that it has many forms in nature, but for some reason quite unknown to us, nature always tends to keep the total energy of the universe constant. You can convert energy from one form to the other, but never create or destroy it. This is what the author refers to as "wonderful property of our universe". Formally it is called - The principle of conservation of energy.