Erklarung der Perihelbewegung des Merkur aus der allgemeinen Relativitatstheorie, pp. 831-839 in Sitzungsberichte der Königlich preussischen Akademie der Wissenschaften, XLVII, 18 November 1915.

Berlin: George Reimer for the Königlich Akademie der Wissenschaften, 1915.

First edition, journal issue in original printed wrappers, of one of Einstein’s most important papers, in which “he presents two of his greatest discoveries. Each of these changed his life” (Pais, p. 253). “In the fall of 1915, Einstein came to the painful realization that the ‘Entwurf’ field equations are untenable. Casting about for new field equations, he fortuitously found his way back to equations of broad covariance that he had reluctantly abandoned three years earlier. He had learned enough in the meantime to see that they were physically viable after all … and on November 4, 1915, presented the rediscovered old equations to the Berlin Academy. He returned a week later with an important modification, and two weeks after that with a further modification. In between these two appearances before his learned colleagues, he presented yet another paper showing that his new theory explains the anomalous advance of the perihelion of Mercury. Fortunately, this result was not affected by the final modification of the field equations presented the following week” (Janssen, pp. 59-60). “The first result [reported in the present paper] was that his theory [of general relativity] ‘explains … quantitatively … the secular rotation of the orbit of Mercury, discovered by Le Verrier, … without the need of any special hypothesis.' This discovery was, I believe, by far the strongest emotional experience in Einstein's scientific life, perhaps in all his life. Nature had spoken to him. He had to be right. ‘For a few days, I was beside myself with joyous excitement’. Later, he told Fokker that his discovery had given him palpitations of the heart. What he told de Haas is even more profoundly significant: when he saw that his calculations agreed with the unexplained astronomical observations, he had the feeling that something actually snapped in him” (Pais, p. 253). “Einstein devoted only half a page to his second discovery: the bending of light [by gravity] is twice as large as he had found earlier. ‘A light ray passing the sun should suffer a deflection of 1".7 (instead of 0".85)’” (Pais, p. 255). The confirmation of this prediction four years later by Dyson and Eddington not only confirmed Einstein’s theory, but also made Einstein world famous.

“Einstein's discovery resolved a difficulty that was known for more than sixty years. Urbain Jean Joseph Le Verrier had been the first to find evidence for an anomaly in the orbit of Mercury and also the first to attempt to explain this effect. On September 12, 1859, he submitted to the Academy of Sciences in Paris the text of a letter to Herve Faye in which he recorded his findings. The perihelion of Mercury advances by thirty-eight seconds per century due to ‘some as yet unknown action on which no light has been thrown … a grave difficulty, worthy of attention by astronomers.’ The only way to explain the effect in terms of known bodies would be (he noted) to increase the mass of Venus by at least 10 per cent, an inadmissible modification. He strongly doubted that an intramercurial planet, as yet unobserved, might be the cause. A swarm of intramercurial asteroids was not ruled out, he believed. ‘Here then, mon cher confrere, is a new complication which manifests itself in the neighborhood of the sun.’ Perihelion precessions of Mercury and other bodies have been the subject of experimental study from 1850 up to the present. The value 43 seconds per century for Mercury, obtained in 1882 by Simon Newcomb, has not changed. The present best value is 43".11 + 0.45. The experimental number quoted by Einstein on November 18, 1915, was 45" ± 5.

“In the late nineteenth and early twentieth centuries, attempts at a theoretical interpretation of the Mercury anomaly were numerous. Le Verrier’s suggestions of an intramercurial planet or planetary ring were reconsidered. Other mechanisms examined were a Mercury moon (again as yet unseen), interplanetary dust, and a possible oblateness of the sun. Each idea had its proponents at one time or another. None was ever generally accepted. All of them had in common that Newton’s 1/r2 law of gravitation was assumed to be strictly valid. There were also a number of proposals to explain the anomaly in terms of a deviation from this law … These attempts either failed or are uninteresting because they involve adjustable parameters. Whatever was tried, the anomaly remained puzzling. In his later years, Newcomb tended ‘to prefer provisionally the hypothesis that the sun's gravitation is not exactly as the inverse square’.

“Against this background, Einstein’s joy in being able to give an explanation ‘without any special hypothesis’ becomes all the more understandable” (Pais, pp. 253-4).

“Let us briefly recapitulate Einstein’s progress in understanding the bending of light. 1907. The clerk at the patent office in Bern discovers the equivalence principle, realizes that this principle by itself implies some bending of light, but believes that the effect is too small to ever be observed. 1911. The professor at Prague finds that the effect can be detected for starlight grazing the sun during a total eclipse and finds that the amount of bending in that case is 0''.87. He does not yet know that space is curved and that, therefore, his answer is incorrect. He is still too close to Newton, who believed that space is flat and who could have himself computed the 0''.87 (now called the Newton value) from his law of gravitation and his corpuscular theory of light. 1912. The professor at Zürich discovers that space is curved. Several years pass before he understands that the curvature of space modifies the bending of light. 1915. The member of the Prussian Academy discovers that general relativity implies a bending of light by the sun equal to 1".74, the Einstein value, twice the Newton value. This factor of 2 sets the stage for a confrontation between Newton and Einstein …

“An opportunity to observe an eclipse in Venezuela in 1916 had to be passed up because of the war. Early attempts to seek deflection in photographs taken during past eclipses led nowhere. An American effort to measure the effect during the eclipse of June 1918 never gave conclusive results. It was not until May 1919 that two British expeditions obtained the first useful photographs and not until November 1919 that their results were formally announced.

“English interest in the bending of light developed soon after copies of Einstein’s general relativity papers were sent from Holland by de Sitter to Arthur Stanley Eddington at Cambridge (presumably these were the first papers on the theory to reach England). In addition, de Sitter’s beautiful essay on the subject, published in June 1916 in the Observatory, as well as his three important papers in the Monthly Notices further helped to spread the word. So did a subsequent report by Eddington, who in a communication to the Royal Astronomical Society in February 1917 stressed the importance of the deflection of light. In March 1917 the Astronomer Royal, Sir Frank Watson Dyson, drew attention to the excellence of the star configuration on May 29, 1919, (another eclipse date) for measuring the alleged deflection, adding that ‘Mr Hinks has kindly undertaken to obtain for the Society information of the stations which may be occupied’. Two expeditions were mounted, one to Sobral in Brazil, led by Andrew Crommelin from the Greenwich Observatory, and one to Principe Island off the coast of Spanish Guinea, led by Eddington. Before departing, Eddington wrote, ‘The present eclipse expeditions may for the first time demonstrate the weight of light [i.e., the Newton value]; or they may confirm Einstein’s weird theory of non- Euclidean space; or they may lead to a result of yet more far-reaching consequences – no deflection’. Under the heading ‘Stop Press News,’ the June issue of the Observatory contains the text of two telegrams, one from Sobral: ‘Eclipse splendid. Crommelin,’ and one from Principe: ‘Through cloud. Hopeful. Eddington’. The expeditions returned. Data analysis began. According to a preliminary report by Eddington to the meeting of the British Association held in Bournemouth on September 9-13, the bending of light lay between 0''.87 and double that value. Word reached Lorentz. Lorentz cabled Einstein, whose excitement on receiving this news after seven years of waiting will now be clearer. Then came November 6, 1919, the day on which Einstein was canonized.

“Ever since 1905 Einstein had been beatus, having performed two first-class miracles. Now, on November 6, the setting, a joint meeting of the Royal Society and the Royal Astronomical Society, resembled a Congregation of Rites. Dyson acted as postulator, ably assisted by Crommelin and Eddington as advocate-procurators. Dyson, speaking first, concluded his remarks with the statement, ‘After a careful study of the plates I am prepared to say that they confirm Einstein’s prediction. A very definite result has been obtained, that light is deflected in accordance with Einstein’s law of gravitation’” (Pais, pp. 303-5).

Janssen, ‘Of pots and holes: Einstein’s bumpy road to general relativity,’ Annalen der Physik 14, Supplement, 2005, pp. 58-85; Pais, Subtle is the Lord, 1982; Weil 76.

Large 8vo (268 x 190 mm). In: Sitzungsberichte der Königlich Preussischen Akademie der Wissenschaften, XLVII, pp.831-839. The entire issue (pp.803-842) offered here, in original printed wrappers. A very fine and unopened copy. Rare in such good condition.

Item #4849

Price: $8,500.00

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