Einstein - Part I

EVERYDAY work on the frontiers of modern physics usually involves complex concepts and extreme conditions. We speak of quantum fields, entanglement or super symmetry, and analyze the ridiculously small or conceptualize the incomprehensibly large. Just as Willie Sutton famously explained that he robbed banks because “that’s where the money is”, so we do these things because “that’s where the Unknown is”. It is an amazing and delightful fact, however, that occasionally this sophisticated work gives answers to childlike questions about familiar things. The world of quarks and gluons, casts brilliant new light on one such childlike question: What is the origin of mass?

            This is an especially appropriate topic for the World Year of Physics, because it relates so closely to the circle of ideas around Albert Einstein’s most famous equation , E = mc^2 . That equation, written in that form, immediately suggests the possibility of converting small quantities of mass into large quantities of energy – a suggestion that was realized, of course, with the development of nuclear reactors and nuclear weapons. It is worth noting, however, that this is not the way the equation appears in Einstein’s original paper. In that paper you do not find E = mc^2 , but rather m = E/c^2. The difference is trivial algebraically, but profound conceptually, for the second (original) form of the equation suggests something quite different : the possibility to derive mass from energy. For a modern physicist , and even for Einstein in 1905, this sounds a deeper resonance. Energy appears a pervasive, primary concept in modern physics , and there is no real prospect of explaining it in terms of something more basic. For mass the situation is quite different. The title of Einstein’s paper is “Does the Inertia of a Body Depend Upon Its Energy Content?”. It shows that from the beginning, Einstein was thinking about questioning the foundations of fundamental physics, not making bombs. Modern physics, as I shall now explain in my next post, answers his question with a resounding “Yes!”