The fall of 2015 marks the centennial of Albert Einstein’s unveiling of the general theory of relativity.  A dramatic result that Einstein derived was the prediction that a light ray grazing the Sun would be deflected about 1.7 seconds of arc.  In 1919 a British expedition confirmed Einstein’s prediction during a solar eclipse.  The social significance of this event was as dramatic as its physics significance.  A deep truth about the universe, predicted by a resident of Germany, was confirmed by a British group one year after World War I ended.  On both sides this accomplishment lifted the public’s imagination—as shown by Einstein suddenly becoming an international celebrity—to something higher than nationalistic squabbles...