California Institute of Technology
Einstein Papers Project




"Einstein's Gyros"


Longtime EPP Editor, József Illy's most recent publication "Einstein's Gyros", can be found in Physics in Perspective. Here's the introduction:

In 1992, W. Schröder and H. J. Treder called attention to Albert Einstein’s short but fascinating detour into geophysics. (1) At the time, they were able to rely only on published papers—in the case of Einstein, on a footnote in his paper on the ether.

Since that time, Einstein’s correspondence of the period has been published and we can draw a more detailed picture of why he embarked on a field so seemingly distant from his main interests. In October 1921, two engineers of the gyrocompass factory of Hermann Anschütz-Kaempfe in Kiel, Germany, launched a series of experiments. They rotated a brass cylinder around its axis, heated it by hot oil, and wondered whether a magnetic field arose around it. (2) It seemed to be a routine test, for there were several gyroscopes rotating in each gyrocompass the firm manufactured and if a magnetic field were to be produced by their mere rotation, it would seriously influence their operation.

Their reason for pursuing these experiments, however, was different: “Even though I cannot yet imagine clearly that a positive effect is to be expected, it is still for me the only reasonable possibility to bring the heat current together with the earth currents, since the latter can only be caused by an irreversible process.” These lines were written in December by Albert Einstein, who had persuaded the engineers to perform the experiment. (3) Heat currents? Earth currents?

In a letter written to Hermann Anschütz-Kaempfe, the owner of the factory, Einstein called the possible positive result “of enormous interest.” (4) Did he mean this with regard to the development of the gyrocompass? No. When, in June 1922, after several failed attempts, the engineers had given up, Einstein remarked, “I thank you very much for repeating the heat-rotation experiment. In thinking about the nature of the Earth’s field, I have got bogged down in improbabilities.” (5) By “field,” he meant the magnetic field of the earth. Thus, the goal of the experiment was to check on a laboratory scale whether the sources of the geomagnetic field are the electric currents circulating in the earth that are sustained by its internal heat. However, before continuing, let us see how Einstein found himself at a gyrocompass factory.

Continue reading: click here for the full text article.

100 Year Anniversary of the Meeting that Confirmed Einstein's Theory

Caltech Twitter Screenshot

On November 6, 1919 the results of Arthur Eddington, Frank Dyson and Andrew Crommelin's expedition-- to observe a total solar eclipse and test Einstein's general theory of relativity-- were presented to the Royal Astronomical Society and Royal Society, in London.

Today in London, on the hundredth anniversary of that meeting, EPP editor Daniel Kennefick will present, with Dr. Meghan Gray of the University of Nottingham, Dr. Carolin Crawford of University of Cambridge and author Ron Cowen at the Royal Astronomical Society.

From the event webpage: Speakers will look at how general relativity underpins modern science. Astrophysicists use it to explain the motion of stars and planets, and understand how matter behaves in extreme environments like the regions around black holes. On the largest scales general relativity is crucial to our understanding of the beginning and ultimate fate of the universe we live in. And in everyday life, it makes possible navigation with satnavs and mobile phones.

Check out Caltech's Twitter page for their announcement of the above and to follow, like and retweet. New York Times subscribers can read Mr. Cowen's Opinion piece in today's digital edition titled How Einstein Became the First Science Superstar.


Q & A with New EPP Editor: Joshua Eisenthal

Eisenthal portrait

1. Welcome to the Einstein Papers Project! Describe the work you were doing in recent years and how that work led you to joining us at the EPP.

After studying Physics and Philosophy at the University of Oxford I spent two years as a science and physics teacher at Capital City Academy in London. In 2018 I completed a PhD in Philosophy at the University of Pittsburgh, where I continued as lecturer in Logic and Philosophy of Science. My dissertation focused on the philosopher-physicist Heinrich Hertz and the influence he had on Ludwig Wittgenstein. Another project I worked on while at Pittsburgh concerned the philosophy of geometry before and after general relativity, particularly Hermann Weyl’s distinctive solution to the “problem of space”.

A focal point of my research is the close interplay between physics and philosophy at the turn of the century and the intellectual upheaval brought about by the transition from classical to modern physics. Einstein, of course, is one of the most important figures in this period: the father of relativity, one of the major progenitors of quantum mechanics, and perhaps the most prominent example of a scientist who remained deeply engaged with philosophy throughout his career.

2. In what ways does your previous research dovetail with or diverge from what we work on at the project?

My recent research on Weyl’s interpretation of general relativity is closely connected with work at the EPP. Weyl’s analysis of geometry led him to a unified theory of gravity and electromagnetism. He quickly communicated his work to Einstein, and although Einstein’s initial response was enthusiastic , he soon discovered a tension with observational data. Weyl’s response to Einstein’s criticism went to the heart of the physical interpretation of geometrical notions, and seems to have influenced Einstein for decades after.

My interest in Wittgenstein, however, brings up questions in the foundations of logic and language which are more distant from Einstein’s work. There appear to be relatively few connections between Einstein and Wittgenstein, which is a little surprising given Wittgenstein’s engineering background and persistent interest in a number of Einstein’s predecessors (Boltzmann, Hertz & Maxwell). Nevertheless, a number of philosophers—especially the members of the Vienna Circle—had parallel interests in Wittgenstein and Einstein, and this is an area of research that I hope to pursue in the future.

3. Does your experience of teaching science continue to affect your working practices? Do you anticipate that it may affect your work as an editor?

One of the lasting impacts of my teaching experience was a sense of the importance and power of clear and effective communication, especially communication to a diverse audience. (If my teenage pupils didn’t find my classes engaging, they would let me know about it very quickly!) The more I’ve learnt about Einstein’s work the more fascinating I have found it, and I am keen to communicate the importance of the work done at the EPP to as broad an audience as possible.

4. Was there a key moment in your formative years that set you on the path to becoming a researcher or philosopher?

I began my undergraduate degree focusing exclusively on physics. However, I soon realized that my interests were always in the theoretical and foundational aspects of physics—those aspects which lie closest to philosophy. (The study of space, time and matter are the most central issues in twentieth century physics, but they are also tied to some of the oldest questions in philosophy.)

The first of two critical moments for me was choosing to study “Physics and Philosophy” as a combined degree. The second was visiting Princeton University as an exchange student, where I wrote a thesis on “Space, Spacetime, and Geometry”. In fact, it was the experience of working on that thesis which set me on the path to becoming a professional researcher today.

Photo by Emily Araújo

A. J. Kox's Biography of H. A. Lorentz Released October 11th

Kox Book Cover; shows LorentzA. J. Kox is Pieter Zeeman Professor of History of Physics, Emeritus, at the University of Amsterdam, Netherlands and Visiting Associate in History at Caltech. Since 1985, Kox has worked with the Einstein Papers Project as an editor of The Collected Papers of Albert Einstein. His most recent book ‘Een levend kunstwerk.’ Hendrik Antoon Lorentz, physicist 1853-1928 was released last week by Balans. This most recent work follows the release of Kox's 2018 publication The Scientific Correspondence of H. A. Lorentz: Volume 2, the Dutch Correspondents.

As described on the Balans website:
He won the Nobel Prize, was a member of the Royal Society and laid the foundation for Einstein's theory of relativity: Lorentz was one of the greatest physicists the Netherlands has ever known. When he died in 1928, telegraph services were stopped for three minutes. Extra trains had to be used to get all interested people to the cemetery on time. Queen Wilhelmina's husband, Prince Hendrik personally came to offer condolences to Lorentz's widow, Aletta Catharina Lorentz.

Lorentz was an icon. Einstein called him a living work of art, a perfect personality, a genius. He was a wise, good person, bridge builder, grandmaster.

For twenty-five years, biographer A. J. Kox immersed himself in Lorentz's life and work. He discovered a person behind the facade of admiration. Clear and nuanced, Kox describes Lorentz's passion, his unique place in science, the importance of his ideas, his international actions just after the First World War, his friendship with Albert Einstein, of whom he was both teacher and critic, his work in Teylers Museum, and his tireless loyalty to a large group of scientists, nationally and internationally.

‘Een levend kunstwerk.’ Hendrik Antoon Lorentz 1853-1928 is an extremely important book about a great man who profoundly influenced international science and played a major social role in the Netherlands.


In Caltech News: "researchers are putting Einstein's theories to new tests"

Whitney Clavin's article, First Overtones "Heard" in the Ringing of a Black Hole posted to the Caltech website on September 11th. The article describes the work of Caltech graduate student Matthew Giesler. Giesler and his colleagues used LIGO data and Einstein's general theory of relativity in their research on gravitational waves and a phenomena called the ringdown.


"Einstein's Working Sheets and His Search for a Unified Field Theory"

Tilman Sauer's most recent publication, "Einstein's Working Sheets and His Search for a Unified Field Theory", was published in the The European Physical Journal H. The paper abstract is as follows: The Einstein Archives contain a considerable collection of calculations in the form of working sheets and scratch paper, documenting Einstein's scientific preoccupations during the last three decades of his life until his death in 1955. This paper provides a brief description of these documents and some indications of what can be expected from a more thorough investigation of these notes.


Q & A with New EPP Editor: Jennifer L. Rodgers

1. Welcome to the Einstein Papers Project! What has been your work in recent years, and how did it lead you to the EPP?

After completing college, I did research for several government agencies on issues related to Nazi Germany, World War II, and the Holocaust. Since finishing my PhD in history at Penn in 2014, I’ve had postdocs in Berlin and Florida, and lectured at Penn. Several things attracted me to the EPP. First, I liked the idea of a challenging new project on a rather unfamiliar subject matter that still intersects with my own interests. Secondly, I welcomed the chance to use documents in diverse ways. At heart, I love nothing more than being in the proverbial salt mine of an archive and plumbing what I can out of the material. Finally, the team-driven atmosphere of the EPP really drew me in when I first came to visit. That same salt mine I adore can also be very isolating and the prospect of having other people to discuss the documents and history with was incredibly appealing.

2. In what ways does your previous research dovetail with or diverge from what we work on at the project?

At first glance, it would appear to most people that my research—as a non-scientist or history of science person—would entirely diverge from Einstein’s work, and what we do here at the project. In reality, there is much more overlap with my research than even I expected, especially once you read against the archival grain, to steal from Ann Stoler.

My book manuscript, The Archives of Humanity: The International Tracing Service, the Holocaust, and Postwar Order, examines aspects of the ongoing refugee and humanitarian crises that swelled because of Nazi racial policies and World War II, two issues Einstein was very engaged with even before Hitler came to power. In fact, while doing the research that underlies the book, I came across correspondence between Einstein and the tracing service in the early 1950s. I remember asking myself at the time: "Why is Albert Einstein intrigued by this place?" Our current and future volumes at the EPP will contain documents that specifically address topics that my own research deals with: refugees, displacement and statelessness, humanitarianism and human rights, and war.

3. You've conducted extensive research in various archives. Can you elucidate how or why working with primary sources is a motivating factor in your work as an historian?

I think the foundation of being a historian is using primary source material. Archives and other primary sources let you peel back layers to get at how the past essentially unfolded, to paraphrase Leopold von Ranke, the founder of the modern historical profession. While historians today have a considerably more refined understanding of this trope, drawing on this core truth to follow the sources, we still use ever-evolving theories and methods to interrogate and contextualize primary material, allowing us to construct considerably more nuanced histories and understandings of the past. I also just love the materiality of being able to physically touch and examine original sources and revel in the "dust" of history.

Photo by Lucinda MacTaggart Rodgers

Riesenfeld Family Visits the EPP

Riesenfelds in EPP conference room

The Einstein Papers Project were delighted to receive a visit from members of the Riesenfeld family earlier this week. As noted in the Spring 2019 issue of Techniques, Caltech received $50,000 for the Einstein Papers Project and $50,000 for the Palomar Observatory from the estate of Shoshana Riesenfeld.

We are truly grateful for the support.

Photo by Emily Araújo

EPP Editor, Daniel Kennefick's book No Shadow of a Doubt out on April 30th

Kennefick Book Cover; shows eclipseDaniel Kennefick is associate professor of physics at the University of Arkansas, Fayetteville and a contributing scientific editor to The Collected Papers of Albert Einstein. He is the author of Traveling at the Speed of Thought: Einstein and the Quest for Gravitational Waves and a coauthor of An Einstein Encyclopedia. Kennefick's forthcoming book, No Shadow of a Doubt: The 1919 Eclipse That Confirmed Einstein’s Theory of Relativity tells the story of the thrilling and contentious scientific expeditions that ushered in the era of relativity.

In 1919, British scientists Arthur Eddington and Frank Dyson led extraordinary expeditions to Brazil and Africa to test Albert Einstein’s revolutionary new theory of general relativity. Their subsequent confirmation of his dramatic prediction – that the path of light rays would be bent by gravity – catapulted Einstein to global stardom. Today, Einstein’s theory is scientific fact. Yet the quest to “weigh light” by measuring its gravitational deflection during the May 29th solar eclipse has since become clouded by myth and skepticism. Daniel Kennefick’s No Shadow of a Doubt provides definitive confirmation of these events through a combination of first-hand accounts and authoritative analysis to show how expedition scientists overcame war, bad weather, and equipment problems to test and prove one of science’s most fundamental theories.

Announcement prepared by Sara Henning-Stout, Senior Publicist, Princeton University Press.

90 Years Ago: March 14, 1929, Einstein’s 50th Birthday

Child's Drawing

Einstein’s fiftieth birthday appears to have been more of a cause for celebration by others than for himself. Having lived under intense scrutiny from the (mostly) adoring public and intrusive journalists for 10 years already, Einstein made valiant efforts to avoid attention from the press on this momentous occasion. He was particularly keen to avoid the hullabaloo ratcheting up for his fiftieth in Berlin. The day before his birthday, a New York Times article, Einstein Flees Berlin to Avoid Being Feted reported that: “To evade all ceremonies and celebrations, he suddenly departed from Berlin last night and left no address. Even his most intimate friends will not know his whereabouts.”

Einstein’s decision allowed him and his family relative respite. While Einstein hid in a countryside retreat, “[t]elegraph messengers, postmen and delivery boys had to wait in line hours today in front of the house No. 5 Haberland Strasse, delivering congratulations and gifts to Albert Einstein on the occasion of his fiftieth birthday today,” according to the March 15 issue of the Jewish Daily Bulletin. Above is one card of the many that Einstein received on and around his birthday; it was made by a pupil at the Jüdische Knabenschule, Hermann Küchler.

After all, an intrepid reporter did find Einstein – in a leafy neighborhood of Berlin called Gatow, half an hour from the city center. A report for avid fans, Einstein Found Hiding on his Birthday, in the March 15 edition of The New York Times provides a gamut of details from the color of his sweater to the menu for his birthday dinner and the array of gifts found on a side table. Happy reading, on this, the 140th anniversary of Einstein’s birth!


Einstein’s 50th will be covered in Volume 16 of The Collected Papers of Albert Einstein. Of the many and varied resources we refer to for historical research, the two used for this web post were: The New York Times archive: Times Machine and the Jewish Telegraphic Agency Archive.

Access to the Times Machine requires a subscription to The New York Times. The card, item number 30-349, is held at the Albert Einstein Archives at HUJI.

Legend to the Letter: Einstein's links to French Scientists is a beautiful online exhibit regarding Einstein's relationship with the Académie des sciences and many of its illustrious members. Documents presented from the Académie's archive are both official and personal. Among them are Einstein's notice of election to the venerable institution and his subsequent registration with the Académie. Other items include letters to his long-time colleague, mathematician Elie Cartan, revealing intellectual exchanges and heartfelt reflections on loss. Click here or on the blue text, above, to go to the Google Arts & Culture site.

Screenshot of Diana Buchwald on CSPAN


Legend to the Letter curated by:
Catherine Bréchignac, physicist, Honorary perpetual Secretary of the Académie des sciences, delegated ambassador of science, technology and innovation
Thibault Damour, physicist, Laureate of the CNRS gold medal, member of the Académie des sciences since 1999
Isabelle Maurin-Joffre, chief curator, director of Académie des sciences archives
Christian Auboyneau, director of sponsorship, development and Rencontres capitales

Watch Diana Kormos Buchwald describing the Einstein Papers Project, Einstein's work habits and more. Click here or on the blue text, above, to see coverage of the EPP on C-SPAN's Cities Tour website.

Screenshot of Diana Buchwald on CSPAN


Interview with EPP Director Airs on C-SPAN March 2 & 3, 2019

A recommendation Otto Stoll sent to Heinrich Ernst on 4 March 1909, ranked the 30 year-old Einstein “among the most important theoretical physicists”. Stoll’s assessment has stood the test of time. Einstein’s legacy as a physicist underpins our work at the Einstein Papers Project.

To learn more about the EPP, see Diana Kormos Buchwald interviewed on C-SPAN’s Book TV, airing Saturday, March 2 at 4:30pm Pacific Time, or Sunday, March 3 at 11am Pacific Time on C-SPAN’s American History TV.

Recognition was not immediate for Einstein. His first published scientific paper “Conclusions Drawn from the Phenomena of Capillarity” came out in the Annalen der Physik on 1 March 1901. At the time of publication Einstein, a recent graduate of the Swiss Federal Polytechnical School (ETH), was unemployed.

As noted by the editors on page 5 of The Collected Papers of Albert Einstein, Volume 2: “Offprints [of Einstein’s first paper] were sent to several prominent physicists, notably Wilhelm Ostwald (who is cited in the paper), as part of Einstein's unsuccessful attempt during that spring to find a position as Assistent at some university.” Then, in spite of a second note by Einstein”—and an effort some, in 2019, might deem an act of helicopter parenting—“Hermann Einstein himself wrote in April 1901 to Ostwald with an appeal that he send words of encouragement or even a job offer to Einstein. Ostwald did not respond.” Of course, 4 years hence, much would change.