I made a discovery, perhaps known to others but new to me: I need not put myself center stage but can rather place myself at the side, like a Greek chorus. As the curtain rises, I can walk to the center and can speak as follows: I wish to tell you of happenings in the twentieth century, as I witnessed them and reflected upon them. You will see me return to center stage, but only occasionally. Once that imagery had gotten hold of me, I went back to Ida and said yes, I shall try.
Dutch-American physicist and science historian (1918–2000)
Abraham Pais (May 19, 1918 – July 28, 2000) was a Dutch-born American physicist and science historian. He served as an assistant to Niels Bohr in Denmark and was later a colleague of Albert Einstein at the Princeton Institute for Advanced Study. Pais wrote books documenting the lives of these two great physicists and the contributions they and others made to modern physics.
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Today we live in the midst of upheaval and crisis. We do not know where we are going, nor even where we ought to be going. Awareness is spreading that our future cannot be a straight extension of the past or the present … The century now approaching its end has been one of indiscriminate violence, it has been perhaps the most murderous one in Western history of which we have record. Yet I would think that what will strike people most when, hundreds of years from now, they will look back on our days is that this was the age when the exploration of space began, the microchip was invented, revolutions in transport and communication virtually annihilated time and distance, transforming the world into a "global village," and relativity theory, quantum mechanics, and the structure of the atom were discovered, in brief that this has been the century of science and technology.
The first thing Bohr said to me was that it would only then be profitable to work with him if I understood that he was a dilettante. The only way I knew to react to this unexpected statement was with a polite smile of disbelief. But evidently Bohr was serious. He explained how he had to approach every new question from a starting point of total ignorance. It is perhaps better to say that Bohr's strength lay in his formidable intuition and insight rather than erudition.
Special relativity killed the classical dream of using the energy-momentum-velocity relations of a particle as a means of probing the dynamic origins of its mass. The relations are purely kinematic. The classical picture of a particle as a finite little sphere is also gone for good. Quantum field theory has taught us that particles nevertheless have structure, arising from quantum fluctuations. Recently, unified field theories have taught us that the mass of the electron is certainly not purely electromagnetic in nature. But we still do not know what causes the electron to weigh.
Weak, electromagnetic, and strong interactions have distinct intrinsic symmetry properties, but this hierarchy of symmetries is not well understood theoretically. Perhaps the most puzzling are the small effects of noninvariance under space reflection and the even smaller effects of noninvariance under space reflection and the even smaller effects of noninvariance under time reversal. It adds to the puzzlement that the latter phenomenon has been observed so far only in a single instance, namely, in the K° - K^-^ system. (These phenomena were first observed after Einstein's death. I have often wondered what might have been his reactions to these discoveries, given his 'conviction' that pure mathematical construction enables us to discover tbe concepts and the laws connectin them'.
Promising steps have been made toward grand unification, the union of weak, electromagnetic, and strong interactions in one compact, non-Abelian gauge group. In most grand unifies theories the proton is unstable. News about the proton's fate is eagerly awaited at this time. Superunification, the union of all four forces, is the major goal. Some believe that it is near and that supergravity will provide the answer. Others are not so sure.
"I introduce the subject of fine structure with a mini-calendar of events. ...
Winter 1914-15. Sommerfeld computes relativistic orbits for hydrogen-like atoms. Pashcen, aware of these studies, carefully investigates fine structures, ....
January 6, 1916. Sommerfeld announces his fine structure formula, citing results to be published by Paschen in support of his answer.
February 1916. Einstein to Sommerfeld: "A revelation!"
March 1916. Bohr to Sommerfeld: "I do not believe ever to have read anything with more joy than your beautiful work."
September 1916. Paschen publishes his work, acknowledging Sommerfeld's "indefatigable efforts.