Being a constant
Conservation Takes several forms energy, momentum, angular momentum, elec charge, among others. However the Symmetry by Coordinate rotation is what implicates the very essence of this mechanisms basic function. The same basic function fully implicates the above mentioned constants
In fact bieng a constant implicates a state of perpetuate. the constances known and unknown to man are present in everything around us via the orbital mechanics of every atom. The Key is knowing that the observance of degridation of what under other conditions such as exposure to other elements are the bieng acted upon from an outside force negating the constants. http://en.wikipedia.org/wiki/Conservation_law