=:

         A good equation is not simply a formula for computation, nor is it a balance scale confirming that two items you suspected were nearly equal really are the same. Instead scientists started using the = symbol as something of a telescope of new ideas—a devise for directing attention to fresh, unsuspected realms. Equations simply happen to be written in symbols instead of words.

          This is how Einstein used the”=” in his equation as well. The Victorians had thought they’d found all the possible sources of energy there were: chemical energy, heat energy, magnetic energy and the rest. But by 1905 Einstein could say, NO, there is another place you can look where you’ll find more. His equation was like a telescope to lead there, but the hiding place was not far away in outer space. It was down here—it had been right in front of his professors all along.

          He found this vast energy source in the one place where no one had thought of looking. It was hidden away in solid matter itself.