Beautiful, Simple and Profound -

Final Development and Testing GR

http://edu-observatory.org/olli/GR/Week1.html

BBC: Albert Einstein Documentary HD (1h 30m) https://www.youtube.com/watch?v=R_yk45m4E3M (start at 44 min) https://www.youtube.com/watch?v=Uvpw6Jh1WGQ (start at 44 min) Reference General relativity: 100 years of the most beautiful theory ever created The cases of Hilbert and Noether are interesting enough to dwell on. In the Spring of 1915, Hilbert invited Einstein to give some lectures at the university at Gottingen, which had become the center of mathematics in Germany and perhaps in the whole Western world. Einstein and Grossmann had published papers expounding a preliminary version of his new theory of gravity, and as Einstein was continuing to work on it Hilbert wanted to know more. He was already familiar with the exotic (to Einstein) mathematics involved (having developed further some of it himself), so as soon as he was able to achieve some understanding of the physics, Hilbert was off and running. At first, Einstein was delighted in finding a new intellectual companion in Hilbert, someone who was able to instantly grasp the core of the problem and tackle it head-on. As he wrote in a letter near the end of November 1915, "The theory is beautiful beyond comparison. However, only one colleague has really understood it", referring to Hilbert. Einstein considered this famed mathematician a genuine "comrade of conviction" who shared his attitude about science as transcending national and ethnic boundaries. That stance might seem obvious today, but it could be considered unpatriotic in the Germany of WWI. But this delight soon turned to resentment as a kind of race ensued, as least in Einstein's imagination, to write down the correct set of equations to describe the gravitational field. Both men understood that this was something big, and the stakes were high. Einstein carried on an intense correspondence with Hilbert and other scientists during the struggle. He became horrified that, after his years of striving, someone else might be able to hijack his work and claim credit for the complete and final theory of gravity. As he said in the same letter, "In my personal experience I have hardly come to know the wretchedness of mankind better than as a result of this theory and everything connected to it." In a note a few days after that to Michele Besso, Einstein continued. "My colleagues are acting hideously in this affair." For his part, Hilbert had already made the remark that would later become somewhat infamous: "physics is much too hard for physicists." While author David Rowe rightfully points out we "know almost nothing about what Einstein and Hilbert talked about during the physicist's week in Gottingen," Hilbert did send off a manuscript with the correct, final field equations that comprised the fundamental content of the theory of general relativity. And he did so almost simultaneously with Einstein's public presentation of these equations. The debate over priority is still being waged by historians, but Einstein and Hilbert had forgotten their differences and moved on almost immediately. In fact, Hilbert relinquished any claim to priority and gave unqualified credit for the theory to the physicist. "Every boy in the streets of Gottingen understands more about four-dimensional geometry than Einstein. Yet, in spite of that, Einstein did the work and not the mathematicians." In the case of Emmy Noether, it is even more difficult to ascertain the exact contributions she made to general relativity. Mathematical research at the time was largely a verbal affair, with formal publication almost an afterthought, and Noether was especially fond of the conversational approach to math. Hilbert had called her to Gottingen for particular help with the immediate aftermath of the discovery of the field equations to work on the very difficult issue of the conservation of energy in general relativity. (This problem is so tricky that it was only in 1981 that Edward Witten was able to prove that the energy derived from the gravitational field equations is guaranteed to be positive.) (Emmy) Noether's Theorem may be the most important theoretical result in modern physics. Correspondence at the time from and to Einstein, including several references to a lost set of notes by Noether, make it clear that she provided critical help and tutelage during the frenzied months leading up to the final appearance of the field equations. But even more important was that her work on the energy problem led to her discovery of the far-reaching result that we now call Noether's theorem and to a mature mathematical understanding of the gravitational equations themselves. No matter how clear Einstein's vision might have been about what the physical content of a relativistic theory of gravity should be, there was no theory until there was a set of equations that expressed those ideas and that satisfied certain mathematical and physical demands of consistency. This is why Einstein struggled for so many years to put his ideas into a form that would be worthy of the name "theory." And it's the best explanation why general relativity should rightfully be credited to a small handful of authors rather than just Einstein himself. The matter of the correct form of the gravitational field equations aside, it is still true that the formulation of the equivalence principle, the seminal thought experiments, and therefore the initial physical impetus for general relativity was certainly Einstein's alone. Let's Recall with Isaac Newton (1642-1727) https://en.wikipedia.org/wiki/Isaac_Newton Amazon: Newton's Principia for the Common Reader (Physics) by S. Chandrasekhar https://www.amazon.com/Newtons-Principia-Common-Reader-Physics/dp/0198517440 The Principia (1687) reigned supreme for more than 200 years. For Newton, time and space were absolute. Along comes Einstein and look what happened in 1905. MiraculousYear1905b.html ON THE ELECTRODYNAMICS OF MOVING BODIES By A. Einstein June 30, 1905 http://www.fourmilab.ch/etexts/einstein/specrel/specrel.pdf Special Relativity https://en.wikipedia.org/wiki/Special_relativity sam.wormley@gmail.com