The Sun has mystified mankind for centuries. In days long gone, primitive people worshiped the Sun or a Sun God. But much more recently, in the later 1800s, people were still mystified because by then science had advanced a great deal and physicists had acquired a significant understanding of thermodynamics and energy. They knew that thermodynamics states that energy can neither be created nor destroyed, and it can only be converted to another form. They also knew how to calculate the heat emitted from burning coal, wood, or anything else.
