Humans began with fire from wood, to fire from charcoal, to coal, to fossil fuel, and natural sources such as hydroelectric, wind, solar. All sorts of energies had always existed around us, waiting for people to discover and gain control of their usage. There was only one type of energy humans obtained by altering natural structures. It was a big leap in our understanding of the universe. The development and usage of nuclear energy.
The success of altering atoms and the conversion between mass and energy signified our advancement in our knowledge of the universe and also brought forth a danger beyond anything that had happened in our history. Humans became threatened by our own weapons. A push of a button could put an end to human history.