If everybody floated with the tide of talk, placidity would soon end in stagnation. It is the strong backward stroke which stirs the ripples, and gives animation and variety.
E=mc2. Energy equals mass times the speed of light squared. The original statement is: If a body gives off the energy L in the form of radiation, its mass diminishes by L/c2. Ist die Tragheit eines Korpers von Seinem Energieghalt Abhangig? 1905