Chasing a Hat Thought Experiment איינשטיין רודף אחרי קרן… הכובע

At the age of 16 Einstein imagined that he was chasing after a beam of light. Could he catch up with it?… Many years later Einstein would chase after and catch up with a wide rim hat. Professor Einstein: the (“Real”) Chasing a Hat Thought Experiment

Prof. Albert Einstein can estimate how much the light of a distant planet is pulled out of its course by the attraction of the sun, but there is nothing in the theory of relativity that tells him how to map the erratic wanderings of a runawy hat…  That day professor Einstein had accepted an invitation to be a guest of the Faulty Club of New York University and plant a tree on the campus at University Heights

Prof. Thomas W. Edmonson, Prof. John C. Hubbard and Captain Henry C. Hathaway, director of public occasions for the University, charged with the duty of escorting the guest to University Heights, decided that Captain Hathaway’s open car would be just the thing. When the party had reached the neighborhood of 133rd St. a wild cry from the back seat caused Capt. Hathaway to throw on the emergency break. He turned his head in time to see Professor Einstein make a flying leap out at one door of the car, his companions emerging only a moment later through the other

Professor Einstein affects a hat of the wide rimmed variety and when a blast of wind snatched it from its owner’s head it “lit running” and was picking a speedy course approximately down the center of Seventh Avenue

By the time he could bring his car to a stop at the curb, Captain Hathawy was hopelessly distanced, the chase already having gone far, with the champion of relativity easily leading his two fellow passengers. Professor Edmonson expanded a quantity of much-needed breath in shouting for somebody to stop that hat, but after all, it was sewer catch basin that brought the case to an end, and it was Professor Einstein who was in at the death, smiling and triumphant over the discomfiture of his less speedy escort

New York Sun, The Campus, June 4, 1921

József Illy, Albert Meets America, How Journalists treated Einstein during Einstein 1921 Travels, 2006

בגיל 16 איינשטיין חשב לעצמו, האם יוכל לרדוף ולהשיג קרן אור? שנים אחר כך הוא רדף אחרי כובע והשיג אותו… והנה עלילות איינשטיין והמרדף אחרי הכובע ברחובות ניו יורק.

ב-1921 פרופסור איינשטיין היה במסע תרומות להקמתה של האוניברסיטה העברית. הוא קיבל הזמנה לבוא ולהרצות באוניברסיטת ניו יורק ולנטוע עץ באוניברסיטת הייטס בעיר.

פרופסור תומס אדמונסון, פרופסור ג’ון הברד וקפטן הסוואי, מנהל מחלקת הדוברות של האוניברסיטה, היה ממונה על ליווי האורח החשוב לאוניברסיטת הייטס. השלושה החליטו שהמכונית הפתוחה של הקפטן תהיה בדיוק מתאימה להסיע את פרופסור איינשטיין לאוניברסיטה. השלושה החלו בנסיעה ואז לפתע בשכונה של רחוב 133 צווחה חזקה מהמושב האחורי גרמה לקפטן הסוואי לבלום את המכונית בחוזקה. הקפטן סובב את ראשו בדיוק בזמן כדי לראות איך איינשטיין קופץ דרך הדלת האחורית של המכונית, כאשר שני הפרופסורים המלווים אותו קפצו מיד אחריו.

איינשטיין לבש כובע רחב שוליים לרגל האירוע החגיגי של נטיעת העץ (בשמש?). לפתע חדרה דרך המכונית הפתוחה רוח והעיפה את הכובע היישר במהירות יחסותית לשדרה השביעית.

פרופסור איינשטיין, שידע שלא מדובר במרדף אחרי קרן אור (!), קפץ מהמכונית הפתוחה (דרך הדלת)… ורדף אחרי הכובע בשדרה השביעית. בינתיים הקפטן ומכוניתו הפתוחה התרחקו מהפרופסור. פרופ’ אדמונסון שאג בכל כוחותיו: “עצרו את הכובע”. אבל כמו שאתם יודעים, פעולה למרחוק (של שאגות) אינה קבילה בפיסיקה.

בהתאם למסורת של ניסויי מחשבה יחסותיים פרופסור איינשטיין היה אמור להמשיך לרדוף אחרי הכובע בדיוק כמו שהוא רדף אחרי קרן האור בגיל 16, לרדוף ולרדוף ולרדוף…. אבל מכיוון שמדובר בכובע ולא בקרן אור…. הכובע לבסוף נחת בתעלת ביוב עירונית שהביאה אותו לכדי עצירה מוחלטת.

איינשטיין המרוצה תפס את כובעו והביס את שני הפרופסורים ואת הקפטן התשוש. בזה תמו עלילות פרופסור איינשטיין והכובע ברחובות ניו יורק.

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The Relativity of Trousers תורת היחסות של המכנסיים

At 8 o’clock Albert Einstein was to appear at a formal reception in his honor (in Chicago). At 7:30 his trunks, containing his dress trousers, had not arrived. His traveling pants had not been ironed

To give the problem its full relative significance: Supposing the dray containing his trunk, and therefore his pants, to be steaming westward from the railroad depot; supposing the earth to be whirling westward at the same time; supposing the earth to be revolving about the sun in still another orbit; and the solar system to be moving another way – in what direction would the professor’s pants be traveling?               x

It becomes apparent at once that the simplest incident may be crowded with the most abstruse problems to a man of science; and the learned doctor reflected this concern as he paced up and down and answered the childish questions of his interviewers, particularly as they asked him to tell them in five minutes what it had taken lifetime to discover

Published in Chicago Herald and Examiner, May 3, 1921

József Illy, Albert Meets America, How Journalists treated Einstein during Einstein 1921 Travels, 2006

In 1940 Einstein’s pants (shabby and baggy) finally arrived

ב-8 בערב אחד של מאי 1921 אלברט איינשטיין היה אמור להופיע בקבלת פנים רשמית לכבודו בשיקגו; ואילו ב-7:30 עדיין לא הגיעה המכולה עם המכנסיים שלו מגוהצים.

“השיקגו הרלד אנד אקזמינר” דיווח שכדי להעניק משמעות יחסותית לבעיה, הועלתה הסברה הבאה: נגיד שהקרון ועליו המזוודה ובה המכנסיים של הפרופסור משייט לו לכיוון מערב בעודו יוצא מתחנת הרכבת. נניח בנוסף שכדור הארץ מסתובב סביב צירו מערבה באותו הזמן; ונגיד שכדור הארץ גם מסובב את השמש עדיין במסלול נוסף; ומערכת השמש נעה לה לכיוון אחר – לאיזה כיוון ינועו המכנסיים של הפרופסור?

מיד אנו עדים לכך שעבור איש המדע המקרה הפשוט ביותר הופך לכזה עמוס בבעיות העמוקות ביותר; והדוקטור המלומד הרהר בנידון בעודו צועד מעלה-מטה (במדרגות המלון); וענה כך לשאלות הילדותיות של המראיינים, במיוחד כאשר הם ביקשו ממנו לתאר להם בחמש דקות את מה שלקח לו לגלות כל החיים.

מתיאור זה של החמש דקות נולדה תורת היחסות של המכנסיים…

דרך אגב, ב-1940 לבסוף הדוקטור מצא את מכנסיו (לא מגוהצים, לאחר מסע ארוך ומפרך ומעט בלויים).

Baggy Pants, 1940, Lucien Aigner

History and Foundations of Quantum Physics

 The Max Planck Institute for the History and Philosophy of Science has inaugurated a very big project: “History and Foundations of Quantum physics”: a project which is an international cooporation of researchers interested in the history and foundations of quantum physics

מכון מקס פלנק להיסטוריה ופילוסופיה של המדע מארגן פרויקט מחקר בינלאומי – היסטוריה ויסודות של פיסיקת הקוונטים. משתתפים בפרויקט חוקרים מכל העולם. רציתי להזכיר שהמנחה שלי לדוקטורט, פרופ’ מרה בלר ז”ל מהאוניברסיטה העברית, הייתה חלוצה במחקר של ההיסטוריה והיסודות של פיסיקת הקוונטים ואני מאוד מקווה שמבצעי המחקר יזכרו זאת. רשימה זו מוקדשת לזכרה.

I would like to emphasize that Professor Mara Beller zal from the Hebrew University of Jerusalem was a known expert in the history and foundations of Quantum physics. I dedicate this short piece to Professor Beller

איינשטיין כידוע לכם התווכח עם נילס בוהר בנוגע לפיסיקת הקוונטים. תוך כדי כך הוא שחרר ביטויים שנהפכו למפורסמים כמו “אלוהים לא משחק בקוביות” ו”פעולה למרחוק של רוחות רפאים”.

פסל של איינשטיין ובוהר בגן גורקי במוסקבה – פסל של V.S. Lemport

כאשר בוחנים את היחס של איינשטיין לתורת הקוונטים צריך לקחת בחשבון את מכלול הגורמים ההיסטוריים, החברתיים והאישיים שבהם היה נתון איינשטיין: איינשטיין היהודי הרגיש שנוא ונרדף באירופה, הוא הרגיש לכוד במתמטיקה של היחסות הכללית (מתמטיקה זו הובילה אותו להצלחה הגדולה הזו); הוא הלך ושקע בפיתוחים המתמטיים שבאו בעקבות היחסות הכללית והוא התבודד בגלל כל מכלול הגורמים האלה. להלן צוהר קטן למשבר שבו היה נתון איינשטיין מתוך ההתכתבות של איינשטיין עם שני בניו, הנס אלברט ואדוארד. ניתן למצוא את ההתכתבות בארכיון איינשטיין. ההתכתבות נמכרה ב-1996.

Einstein wrote to Hans Albert and Eduard Einstein, December 12, 1922, Kyoto. “The trip is wonderful, even though Japan is rather tiring. I have already given 13 lectures… Now you will really get the Nobel prize. Look around for a house. The surplus will be deposited somewhere in your names… After my return (end of March or beginning of April) I have to travel to Stockholm to receive the prize… Papa”. And

In 1921, the physics Nobel Prize was given to Einstein for his “work on theoretical physics, and in particular for your discovery of the law of the photoelectric effect, without taking into account the value which will be accorded your relativity and gravitation theories after these are confirmed in the future”. And

The announcement was made while Einstein and his wife Elsa were on route to Japen, where he gave a series of lectures on…  Relativity in November and December 1922. In 1923 Einstein gave the whole Nobel Prize, amounting to 121,000 Swedish Kroner ($32,000), to his first wife Mileva and the children, as he had promised; this enabled Mileva to purchase three houses in Zurich, in one of which she lived for the rest of her life. Einstein never received a Nobel prize for his work on either special or the general theory of relativity

Einstein to Eduard Einstein, December, 1933, Princeton. “Terrible things have happened since we last saw each other… I am one of the most hated men, and even the Swiss newspapers speak against me. But I have kept my sense of Humor… Men are like the sea, sometimes calm and friendly, sometimes stormy and treacherous, but on the whole, just water… Papa”. And

Here

Einstein to Hans Albert Einstein, January, 1935, Princeton. “I am so completely in the clutches of the mathematical devil that I have nothing left for private correspondence. I’m pursuing such hopeless goals that my head is good for nothing else…. Papa”. And

Einstein to Hans Albert Einstein, February, 1936, “I am working very hard on a theory of matter based on the general theory of relativity. I have never encountered such mathematical obstacles. A very famous young colleague [Nathan Rosen?] is working with me, and I am enjoying our daily collaboration very much… Pater”. And

Hans Albert Comes to America. Einstein to Hans Albert, March 3, 1937, Princeton, “I am not as tough as I once was, but it’s better to work all out than to be a well-preserved shell… Papa”. And

Einstein to Hans Albert, August 30, 1937, Princeton, “Because I live in isolation my English is rotten…Papa”. And

Einstein to Hans Albert, October 30, 1938, Princeton. Hans Albert and his family are in America. Einstein is pleased “especially since you are burdened with the name Einstein, which is now detested in Germany”. And

Einstein to Hans Albert Einstein, October 19, 1942. “My work is going rather well, in that I have finally found the right form for the ‘Greenville idea’, after scribbling over mountains of paper with false starts. It will soon have progressed to the point where I can make a comparison with reality… Papa”. And

Einstein was searching to make comparison with REALITY; he lived in isolation (is this reality?); he was so completely in the clutches of the mathematical devil: a theory of matter based on the general theory of relativity; and he was one of the most hated men (a Jew in Nazi-era Europe and later a gypsy in America). However, he received a Nobel prize for his quantum of light paper

Albert Einstein and the Theory of Relativity איינשטיין ותורת היחסות

Age 16. Between 1894 and 1895 Einstein writes an essay and sends it to his uncle Caesar Koch. He believes in the ether. Einstein is also familiar with the principle of relativity in mechanics

A year later, in 1895-1896, while in Aarau, Einstein conceives of a thought experiment: Einstein chases a light beam

In 1899 Einstein studies Maxwell’s electromagnetic theory

Around 1898-1900Einstein invents the magnet and conductor thought experiment

Between 1899 and 1900 Einstein is occupied with the contradiction between the Galilean principle of relativity and the constancy of the velocity of light in Maxwell’s theory

Between 1899 and 1901 Einstein is interested in ether drift experiments, and appears to have designed at least two experiments, the first in 1899

In 1901 Einstein still accepts the Galilean kinematics of space and time, in which the Galileian principle of relativity holds good

In 1902 Einstein reads Hendryk Antoon Lorentz’s 1895 seminal work on electron theory

Between 1901 and 1903 Einstein is working with the Maxwell-Hertz equations for empty space. He tries to find solutions to two problems

Magnet and conductor experiment and Faraday’s induction law lead to a conclusion that there is an asymmetry in the explanation depending on whether the magnet moves or the conductor moves. Einstein analyzed the magnet and conductor thought experiment according to Maxwell’s theory and the Galilean transformations. But covariance of Maxwell equations failed

Einstein confronts a conflict between the principle of Galilean relativity and the constancy of the velocity of light

Between 1901 and 1903 Einstein drops the ether hypothesis and chooses the principle of relativity instead of the postulate of the constancy of the velocity of light, and finds a (temporary) solution for his conflict in the form of an emission theory

Einstein seems to have pondered with this problem for an extra year, from 1903-1904 until almost spring-summer 1904. Einstein discusses Fizeau’s experiment using emission theory. He demonstrates, by using Fizeau’s celebrated experimental result, why this standpoint of emission theories cannot hold true

Towards spring-summer 1904 Einstein dropps emission theory and returns to Lorentz’s theory. He spends almost a year in vain trying to modify the idea of Lorentz in the hope of resolving the above problem. Einstein tries to discuss Fizeau’s experiment in Lorentz’s theory [In 1895 Lorentz managed to derive the Fresnel Formula from the first principles of his theory (stationary ether and moving electrons) without the need of any partial ether drag. Lorentz thus adhered to Fizeau’s original 1851 experimental result, but not to Fresnel’s theoretical interpretation of partial ether drag hypothesis, used to derive his dragging coefficient]. Finally

Age 26. In spring 1905, Einstein found the final solution, the “step”, which solved his dilemma

For footnotes, references, and further details please consult my papers

Centenary of the Death of Poincaré – Einstein and Poincaré 2012 פואנקרה ואיינשטיין

לרגל מאה שנה למותו של פואנקרה, פרסמתי בשלושה חלקים מחקר על הנרי פואנקרה, תרומתו בתחום של תורת האלקטרון והאלקטרודינמיקה של הגופים בתנועה והשאלה האם פואנקרה הגיע לתורת יחסות ולגילויים שאותם אנו מוצאים בתורת היחסות הפרטית לפני או במקביל לאיינשטיין. כמובן שהשאלה היא מעט יותר מורכבת ולא פשטנית כפי שהצגתי אותה כאן. בנושא זה כתבתי את עבודת הדוקטורט שלי והמאמרים הם סיכום ועדכון של הדוקטורט שלי שנכתב לפני 14 שנה.

A Biography of Poincaré  – Researcher in dynamics of the electron and electrodynamics –  2012 Centenary of the Death of Poincaré. Here

On January 4, 2012 (the centenary of Henri Poincaré’s death) a colloquium was held in Nancy, France the subject of which was “Vers une biographie d’Henri Poincaré”. Scholars discussed several approaches for writing a biography of Poincaré

 

I present a personal and scientific biographical sketch of Poincaré and his contributions to electrodynamics of moving bodies, which does not in any way reflect Poincaré’s rich personality and immense activity in science. When Poincaré traveled to parts of Europe, Africa and America, his companions noticed that he knew well everything from statistics to history and curious customs and habits of peoples. He was almost teaching everything in science. He was so encyclopedic that he dealt with the outstanding questions in the different branches of physics and mathematics; he had altered whole fields of science such as non-Euclidean geometry, Arithmetic, celestial mechanics, thermodynamics and kinetic theory, optics, electrodynamics, Maxwell’s theory, and other topics from the forefront of Fin de Siècle physical science

As opposed to the prosperity of biographies and secondary papers studying the life and scientific contributions of Albert Einstein, one finds much less biographies and secondary sources discussing Poincaré’s life and work. Unlike Einstein, Poincaré was not a cultural icon. Beginning in 1920 Einstein became a myth and a world famous figure. Although Poincaré was so brilliant in mathematics, he mainly remained a famous mathematician within the professional circle of scientists. He published more papers than Einstein, performed research in many more branches of physics and mathematics, received more prizes on his studies, and was a member of more academies in the whole world. Despite this tremendous yield, Poincaré did not win the Nobel Prize

Most famous is Poincaré’s philosophy of conventionalism, which sprang out of his research into geometry during a period (the end of the 1880’s) when non-Euclidean geometries were a matter of a consistent possibility. Poincaré developed two kinds of conventionalism, conventionalism applicable to geometry and conventionalism for the principles of physics. Both sprang from Poincaré’s mathematical group theory

In addition to the geometries of Euclid, Lobachewski, and Riemann, Poincaré proposed another geometry, the truth of which was not incompatible with the other geometries; he called it the “fourth geometry”. The first time that Poincaré’s fourth geometry appeared in print was in 1891

Einstein did not feel at ease with Poincaré’s standpoint. In 1992 Michel Paty commented on Einstein’s presentation of Poincaré’s conventionalism in 1921, “Actually this is not exactly Poincaré’s point of view, but a translation of it made by Einstein in his own perspective, that is according to his conception of physical Geometry”. See

Scott Walter’s papers here

And Peter Galison’s book Einstein’s Clocks, Poincare’s Maps here

Review by John Stachel: here and by Alberto Martínez here

Scientific contributions in electrodynamics: Before 1905, Poincaré stressed the importance of the method of clocks and their synchronization, but unlike Einstein, magnet and conductor (asymmetries in Lorentz’s theory regarding the explanation of Faraday’s induction) or chasing a light beam and overtaking it, were not a matter of great concern for him

In 1905 Poincaré elaborated Lorentz’s electron theory from 1904 in two papers entitled “On the Dynamics of the Electron”. Poincaré’s theory was a space-time mathematical theory of groups at the basis of which stood the postulate of relativity; Einstein’s 1905 theory was a kinematical theory of relativity

Poincaré did not renounce the ether. He wrote a new law of addition of velocities, but he did not abandon the tacit assumptions made about the nature of time, simultaneity, and space measurements implicit in Newtonian kinematics

Although he questioned absolute time and absolute simultaneity, he did not make new kinematical tacit assumptions about space and time. He also did not require reciprocity of the appearances, and therefore did not discover relativity of simultaneity

These are the main hallmarks of Einstein’s special theory of relativity. Nevertheless, Poincaré had arrived at many novel findings that went way beyond Fin de Siècle physics. here

Here

Read other point of views: Olivier Darrigol’s papers here and here

Darrigol, Olivier, “Henri Poincaré’s criticism of fin de siècle electrodynamics”, Studies in History and Philosophy of Modern Physics 26, 1995, pp. 1-44. here

Darrigol, Olivier, Electrodynamics from Ampère to Einstein, 2000, Oxford: Oxford University Press. Here

Mass-energy equivalence: In 1900 Poincaré considered a device creating and emitting electromagnetic waves. The device emits energy in all directions. As a result of the energy being emitted, it recoils. No motion of any other material body compensates for the recoil at that moment. Poincaré found that as a result of the recoil of the oscillator, in the moving system, the oscillator generating the electromagnetic energy suffers an “apparent complementary force”. In addition, in order to demonstrate the non-violation of the theorem of the motion of the centre of gravity, Poincaré needed an arbitrary convention, the “fictitious fluid”

Einstein demonstrated that if the inertial mass E/c2 is associated with the energy E, and on assuming the inseparability of the theorem of the conservation of mass and that of energy, then – at least as a first approximation – the theorem of the conservation of the motion of the centre of gravity is also valid for all systems in which electromagnetic processes take place

Before 1905 (and also afterwards) Poincaré did not explore the inertial mass-energy equivalence

Einstein was the first to explore the inertial mass-energy equivalence. In 1905 Einstein showed that a change in energy is associated with a change in inertial mass equal to the change in energy divided by c2

Here

For a different point of view: Darrigol, Olivier, “Poincaré, Einstein, et l’inertie de l’énergie”, Comptes rendus de l’Académie des sciences IV 1, 2000, pp. 143-153. Here

See also this paper by Stephen Boughn and  Tony Rothman. A report of the paper here

Here

Did Poincaré influence Einstein on his way to the Special theory of relativity? One differentiates two kinds of questions here

  1What was the effect of Poincaré’s studies on the development of the Special Theory of relativity? and

 2What was the effect Poincaré’s research may have had on the development of Einstein’s own pathway towards the Special Theory of Relativity? hence

Poincaré did contribute to the theory of relativity a great deal. His 1905 space-time theory of groups greatly influenced Minkowski on his way to reformulate and recast mathematically the special theory of relativity. In addition, he arrived at many interesting ideas. However, it appears from examining the primary sources that Poincaré did not influence Einstein on his route to the special theory of relativity. See my papers here