Happy 100th Anniversary to Einstein’s General Theory of Relativity!

relativity jacketToday is the final day of our popular #ThanksEinstein series, in which an array of prominent scholars and scientists have shared their insights and reflections on relativity, Einstein, and how his work inspired their own careers. Scroll through this week’s blog posts to read pieces by Daniel Kennefick, Katherine Freese, Hanoch Gutfreund, Jürgen Renn, Alice Calaprice, Jimena Canales, J.P. Ostriker, and many more special features, including this piece on Einstein’s final days.

Einstein’s General Theory of Relativity celebrates its 100 year anniversary today. November 25, 1915, during a particularly strenuous time in his life, is when Einstein submitted his final version of the general theory of relativity to the Prussian Royal Academy, complete with the field equations that define how the force of gravity arises from the curvature of space and time by matter and energy. The theory, which is the current theory of gravitation in modern physics, has implications for everything from black holes to the idea of universe expansion. It gained rapid popularity after its conception in 1915, and in the early 1920s alone, it was translated into ten languages. Fifteen editions in the original German appeared over the course of Einstein’s lifetime.

Princeton University Press has released a special edition of Relativity: The Special and the General Theory to commemorate the anniversary, including commentary from Hanoch Gutfreund and Jürgen Renn, Einstein experts, as well as additional content such as title pages from several language translations. You can browse through them in the slideshow below. Happy 100th to the general theory of relativity! Science wouldn’t be the same without you.

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Relativity Title Page, English Edition

Relativity Title Page, Chinese Edition

Relativity Cover, Chinese 1921 Edition

Relativity Cover, Czech Republic 1923 Edition

Relativity Cover, German Edition

Relativity Title Page, Japanese Edition

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Was Einstein the First to Discover General Relativity?

Today the world celebrates the day 100 years ago that Albert Einstein submitted his final version of the general theory of relativity to the Prussian Royal Academy. A theory of gravitation with critical consequences, it completely transformed the field of theoretical physics and astronomy. Einstein has long been celebrated and popularized for his contribution, but some have continued to ask whether he was, in fact, the first to discover general relativity. Daniel Kennefick, co-author of An Einstein Encyclopedia, looks at the debate:

Einstein’s Race

By Daniel Kennefick

On November 25, 1915 Einstein submitted one of the most remarkable scientific papers of the twentieth century to the Prussian Academy of Sciences in Berlin. The paper presented the final form of what are called the Einstein Equations, the field equations of gravity which underpin Einstein’s General Theory of Relativity. Thus this year marks the centenary of that theory. Within a few years this paper had supplanted Newton’s Universal Theory of Gravitation as our explanation of the phenomenon of gravitation, as well as overthrown Newton’s understanding of such fundamental concepts as space, time and motion. As a result Einstein became, and has remained, the most famous and celebrated scientist since Newton himself.

EinsteinBut what if Einstein was not the first scientist to publish these famous equations? Should they be called, not the Einstein equations, but the Einstein-Hilbert equations, honoring also the German mathematician David Hilbert? In 1915, Einstein visited Hilbert in Gottingen, and Hilbert convinced him that the goal of a fully general relativistic theory was achievable, something Einstein had nearly convinced himself could not be done. Einstein returned to work, and by November, he had found the field equations which give General Relativity its final form. However, Hilbert also worked on the ideas Einstein had discussed with him and published a paper discussing how Einstein’s theory fitted in with his own ideas on the role of mathematics in physics.

The argument for honoring Hilbert lies in a paper written by him which included the Einstein equations, derived from fundamental principles. This paper, while appearing several months after Einstein’s, was submitted on November 20, and Hilbert even sent Einstein a copy which probably reached Einstein before he submitted his own paper. In fact, a few people have even gone so far as to propose that Einstein might have stolen the final form of his equations from Hilbert.

Of course even if that were true, we are talking only about one final term in the equations (Einstein had published a close to correct version earlier in the month) and to Einstein would still belong sole credit for the enormous amount of work which went into the argument by which equations with these unique properties were singled out in the first place. We would still recognize Einstein for the critical physical thinking, while acknowledging Hilbert’s superior mathematical ability in more quickly finding the final correct form of the equations. Still, perhaps Hilbert would deserve a share of the credit for that final step. Why then do the centenary celebrations mention Einstein only and omit Hilbert almost completely?

One reason is that in the late 1990s a historian working on Hilbert named Leo Corry made a remarkable discovery. He found a copy of the proofs of Hilbert’s paper, with a printers stamp dating it to December 6, 1915. These proofs show that Hilbert made significant changes to the paper after this date. In addition, the proofs do not contain the Einstein equations. The proofs have been cut up here and there (probably by the printers themselves as they worked), so it is possible that the equations would be there if we had the missing pieces. But it is also quite possible that amidst the changes Hilbert made to the paper, he took the opportunity to include the final form of the equations from Einstein’s paper. Indeed some of the changes he made after December 6 were to update his argument from earlier versions of Einstein’s theory to the later version.

Certainly it was Einstein who felt himself to be the injured party in this short-lived priority dispute (arguably the only occasion in his life when Einstein found himself in such a dispute). He complained to a friend that Hilbert was trying to “nostrify” his theory, to claim a share of the credit. Einstein complained to Hilbert himself indeed, and some of the changes made in proofs by Hilbert included the addition of remarks giving credit for the basic ideas behind the theory to Einstein. At any rate, Einstein tried not to let proprietary feelings color his feelings of gratitude for Hilbert. He recalled well that Hilbert had played an important role in encouraging Einstein to return to his theory at a time when Einstein had, to some extent, given up on his original goals. On December 20, 1915, he wrote to Hilbert:

“There has been a certain resentment between us, the cause of which I do not want analyze any further. I have fought against the feeling of bitterness associated with it, and with complete success. I again think of you with undiminished kindness and I ask you to attempt the same with me. It is objectively a pity if two guys that have somewhat liberated themselves from this shabby world are not giving pleasure to each other.” (translated and quoted in Corry, Renn and Stachel, 1997).

So if Einstein was becoming the new Newton, as the man who solved the riddle of gravity, he was far from being a new Newton in another sense; of being the sort of man who carries on scientific grudges to the detriment of his friendship with the other great thinkers of his day.

Daniel Kennefick is associate professor of physics at the University of Arkansas, an editor of the Collected Papers of Albert Einstein, and the author of An Einstein Encyclopedia and Traveling at the Speed of Thought: Einstein and the Quest for Gravitational Waves (Princeton).

For more on Einstein’s field equations, check out this article by Dennis Lehmkuhl at Caltech.

The Final Days of Albert Einstein


Albert Einstein’s time on earth ended on April 18, 1955, at the Princeton Hospital.

In April of 1955, shortly after Einstein’s death, a pathologist removed his brain without the permission of his family, and stored it in formaldehyde until around 2007, shortly before dying himself. In that time, the brain of the man who has been credited with the some of the most beautiful and imaginative ideas in all of science was photographed, fragmented —small sections parceled to various researchers. His eyes were given to his ophthalmologist.

These indignities in the name of science netted several so-called findings—that the inferior parietal lobe, the part said to be responsible for mathematical reasoning was wider, that the unique makeup of the Sulvian fissure could have allowed more neurons to make connections. And yet, there remains the sense that no differences can truly account for the cognitive abilities that made his genius so striking.

Along with an exhaustive amount of information on  the personal, scientific, and public spheres of Einstein’s life, An Einstein Encyclopedia includes this well-known if macabre “brain in a jar” story. But there is a quieter one that is far more revealing of the man himself: The story in which Helen Dukas, Einstein’s longtime secretary and companion, recounts his last days. Dukas, the encyclopedia notes, was “well known for being intelligent, modest, shy, and passionately loyal to Einstein.” Her account is at once unsensational and unadorned.

One might expect a story of encroaching death, however restrained, to chronicle confusion and fear. Medically supported death was a regular occurrence by the middle of the 20th century, and Einstein died in his local hospital. But what is immediately striking from the account is the simplicity and calmness with which Einstein met his own passing, which he regarded as a natural event. The telling of this chapter is matter of fact, from his collapse at home, to his diagnosis with a hemorrhage, to his reluctant trip to the hospital and refusal of a famous heart surgeon. Dukas writes that he endured the pain from an internal hemorrhage (“the worst pain one can have”) with a smile, occasionally taking morphine. On his final day, during a respite from pain, he read the paper and talked about politics and scientific matters.

“You’re really hysterical—I have to pass on sometime, and it doesn’t really matter when.” he tells Dukas, when she rises in the night to check on him.

As Mary Talbot  writes in Aeon, “Apprehending the truth that all things arise and pass away might be the ultimate groundwork for dying.” And certainly, it would be difficult to dispute Einstein’s wholehearted dedication to the truth throughout his life and work. His manifesto, referenced here by Hanoch Gutfreund on the occasion of the opening of the Hebrew University, asserts, “Science and investigation recognize as their aim the truth only.” From passionate debates on the nature of reality with Bohr, to his historic clash on the nature of time with Bergson, Einstein’s quest for the truth was a constant in his life.  It would seem that it was equally so at the time of his death. What, then, did he believe at the end? We can’t know, but An Einstein Encyclopedia opens with his own words,

Strange is our situation here upon earth. Each of us comes for a short visit, not knowing why, yet sometimes seeming to divine a purpose….To ponder interminably over the reason for one’s own existence or the meaning of life in general seems to me, from an objective point of view, to be sheer folly. And yet everyone holds certain ideals by which he guides his aspiration and his judgment. The ideals which have always shone before me and filled me with the joy of living are goodness, beauty, and truth. To make a goal of comfort or happiness has never appealed to me; a system of ethics built on this basis would be sufficient only for a herd of cattle.

Read a sample chapter of An Einstein Encyclopedia, by Alice Calaprice, Daniel Kennefick, & Robert Schulmann here.

#ThanksEinstein: Alice Calaprice on the man behind the myth

Thanks Einstein Meme 4

Becoming an Einstein Author

By Alice Calaprice

Alice Calaprice is the editor of the hugely popular collection of Einstein quotations that has sold tens of thousands of copies worldwide and been translated into twenty-five languages. This is the story of how her knack for German and quest for full-time work in Princeton, New Jersey led her to a career she never imagined.

As a child I did not dream of someday becoming an author of books about Albert Einstein, nor did I contemplate the possibility even after graduating from UC Berkeley in the 1960s. Such an idea would not even have occurred to me. Along with my interest in science, languages, cultures, and history, it was eventually serendipity that took me there.

In the late 1970s, after my family had settled well into the routine of raising school-age children in Princeton, New Jersey, I assigned myself the task of finding full-time work. I had recently completed a course in the then relatively new field of computer technology, hoping it would help bolster a future career. One day in early 1978, a friend told me about a new venture being undertaken by Princeton University Press: the publication of the papers of Albert Einstein in a voluminous series that would span many years. An intriguing project, for sure, but I did not imagine myself being a part of it.

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Calaprice at an Einstein statue in Washington DC (“worshipping at Einstein’s feet”).

Soon after, however, the founding editor of the project, physicist John Stachel, and I met after he had started some preliminary work on the papers. It interested him that I was a native German speaker, had spent time around computers, and wasn’t averse to physics jargon and working with physicists, being married to one at the time. He had been looking for someone for a specialized task: helping him prepare three electronic indexes of the contents of the Einstein archive. He explained that the archive contained about 10,000 documents, consisting of Einstein’s writings, correspondence, and third-party materials. The indexes would give him an overview of the archive’s size and contents–information crucial to the planning stages of the enormous undertaking.

Although the Collected Papers of Albert Einstein would be administered and published by the university press, the archive and his office were located at the nearby Institute for Advanced Study, in the same building where Einstein himself had worked during the last two decades of his life. Stachel asked if I was interested in helping to jump-start this initial phase of the project. The timing turned out to be perfect, and I agreed. I had no inkling that I was about to jump-start a lifelong career as well.

Hello, Einstein

This assignment, which required perusing and often carefully reading each document in the archive’s files, gave me the chance to familiarize myself with the details of Einstein’s legacy and life, with which I was not particularly familiar. It was also an opportunity to revive my long-neglected German-language aptitude, which had waned over the years. Einstein wrote almost exclusively in his native language, even after he came to America from Germany in 1933; his correspondence and papers were generally translated by his secretary or assistants. I was surprised by some of the particulars about his life. He was not so saintly, after all, and besides transforming scientific thinking he had also done ordinary things like play the violin and love animals.

My curiosity was piqued. I quickly became an autodidact, reading supplementary articles and books so I could put the archival material into context. Names of Einstein’s family, friends, and colleagues became familiar, as did the terms for concepts in physics used by him and his cohorts. The prewar and wartime venues and events in Germany became clearer, alive, and more personal. Berlin, the city of my wartime birth, took on new meaning: I discovered that the Einstein family had lived in the same neighborhood as my family, but, unlike them, we did not have to flee persecution. We did flee the city during the Allied bombings of 1945, long after the Einsteins had already departed for America. After short stints in various villages, we coincidentally ended up in Bad Cannstatt in southwestern Germany, which I later learned was also the ancestral home of Einstein’s mother. And, finally, both of us had found our way to Princeton, if at different times, by different routes, and for different reasons. After I had oriented myself to my new surroundings, I loved coming to work. I had found a stimulating job that suited me well. Not only was the timing of my employment in the archive ideal for me personally, but the times were exciting, too. The centennial of Einstein’s birth took place at the Institute—among other worldwide venues—in 1979. Some of Einstein’s assistants and collaborators were still alive and gave firsthand accounts of their recollections in a symposium on the campus. I was able to attend these talks.

Einstein’s Inner Circle

There and at other times, I met many people who had been associated with Einstein either directly or were now members of boards that were planning the eventual publication of his papers. Outstanding among these was Helen Dukas, Einstein’s longtime, modest, and intensely loyal secretary, who, after his death in 1955, had become the first archivist of his papers. Now in her early eighties, she still came to work almost daily. Her office was around the corner from mine on the third floor of Fuld Hall. She stopped by to chat every morning after exiting the elevator located across from my office, often inspecting the never-ending clutches of house finches nesting outside my window in spring and summer. She came to our house for dinner, and she invited my family to be her guests at the swimming pool in the Institute Woods.

At Helen’s crowded memorial service after her death in 1982, I heard her old friend Otto Nathan, the executor of Einstein’s estate, tearfully proclaim, “When Helen died, Einstein died a second time.” The Institute, a cosmopolitan place of world-renowned scholars, where foreign languages were heard more often than English, was a place where one could thrive professionally and personally.

We completed the indexes by the 1980 deadline. Because the 10,000 estimated documents had more than quadrupled to 42,000, we had hired a part-time assistant to help accomplish the task. I spent long hours working off-site in the evenings, when mainframe computers at the university’s Computer Center and, later, in my husband’s cyclotron laboratory in the physics department, were more readily available for use.

Herb Bailey, the well-regarded director of Princeton University Press who had long advocated for publication of the Collected Papers, was apparently pleased with my work. He now offered me a position in the editorial offices at the Press’s historic Scribner building on the university’s campus. My first day of work was on April Fool’s Day 1980, but I was assured my employment was not a joke. John Stachel continued his sole editorship of the papers at the Institute, and later at Scribner with a small staff. I was in touch with the group almost daily, grounding my interest in what came to be known as the Einstein Papers Project.

Fluent in Einstein

Five years later, after I had become a senior editor at PUP, I had the opportunity to again read the documents and letters that were about to be published in volume 1 of the Collected Papers. In 1985, the first manuscript in the series was turned over to the Press’s editorial office, and I was asked to take charge. I helped to set an editorial style for the series, copyedited the volumes as they arrived in-house, and became administrator and “principal investigator” of the concomitant National Science Foundation-funded English-translation project. Over a span of almost thirty years, I copyedited all fifteen of the volumes in the series—more recently as a freelancer—that have been published so far, including the translated volumes. Alas, so much reading, yet I never succeeded in understanding physics and relativity theory! Despite this shortfall, I became the liaison for nonscientific Einstein-related inquiries, book projects, film documentaries, and even the movie IQ in the early 1990s. I was a resource on matters dealing with Einstein, consistently learning something new in the process and having contact with an assortment of Einstein aficionados around the world. At the same time, I handled many other editing projects, mostly in the sciences. Surrounded by a group of wonderful, supportive, and good-humored colleagues and a continuously changing stream of engaging authors, I was having the time of my life. Those years set the stage for the twenty years ahead.

In 1995, I had an especially good year. First, it was the year I began mitigating my restlessness at home by taking annual trips to unlikely parts of the world, and I went to eastern Siberia with a small group of fellow nature lovers. Second, on my return, I received the news that I would receive the national Literary Market Place (LMP) Award for Individual Editorial Achievement in Scholarly Publishing, to be presented at the New York Public Library the following year. Third, Trevor Lipscombe, PUP’s acquisitions editor in physics at the time, discussed with me the prospect of publishing a book of quotations by Einstein. Like all those familiar with Einstein’s life, Trevor was aware that the physicist was multidimensional and fearless in expressing opinions on a variety of topics of interest to many: there was much more to him than relativity theory. Unbeknownst to Trevor, I had already collected many quotations while working on the indexes and copyediting the first few volumes of the Collected Papers—simply because they had struck a chord with me. When I showed him my blue box of index cards containing the quotations, he suggested I write the book myself rather than find someone else to do so. I was excited at the prospect of being on the other side of the author/editor relationship.

The Quotable Einstein is born

Soon after I returned from another adventure trip about a year later, this time into the Amazon Basin in northeastern Peru, the first edition of The Quotable Einstein was published. It contained four hundred quotations and their sources, arranged by topic, such as Einstein on religion, on his family, on Jews, on politics, on science and scientists, and so forth. The initial print run was modest, as there were doubts that the book would have wide appeal. The volume quickly sold out, however, and was reprinted six times. For a long time, it was at the top of PUP’s sales list, which I admired in disbelief and awe whenever one was posted on the bulletin board. Three more enlarged editions followed at approximately five-year intervals, and more than twenty-five foreign-language translations have been contracted, some in obscure languages I had never heard of. I believe these books were successful because they showed Einstein in all his guises, in his own uncensored words—a human being beyond the prevailing hagiographic and absent-minded-professor myths and falsely attributed quotations. The Ultimate Quotable Einstein, containing about 1,600 documented quotations and published in 2008, was my fourth and final contribution to this series of quotation books.

Because of the success of these volumes, I was now, to my surprise, perceived as an authority. I was asked to give Calaprice_Einstein_Encyclopediatalks for nonacademic audiences and participate in television shows and documentaries. I was invited to the German embassy to celebrate the special relativity centennial in 2005, and sat next to the German ambassador for lunch. I had book signings. I appeared on Ira Flatow’s “Science Friday” at the NPR studio in New York, along with Dennis Overbye of the New York Times. I have to confess that I found these new challenges difficult. I felt more comfortable doing research and writing, so I agreed to write three more books for other publishers who approached me.

Now, well into retirement in California, I am back with PUP for my swan song in the Einstein genre. Having often felt the need for a concise Einstein reference guide while doing research, I had submitted to the publisher an informal proposal to write An Einstein Encyclopedia. My expertise on specialized topics relating to Einstein is limited, so two Einstein scholars with broad experience on the Einstein Papers Project, historian Robert Schulmann and physicist Dan Kennefick, fortunately agreed to join me in this project as co-authors. Our final proposal was accepted, the three of us had a productive long-distance collaboration, and, best of all, we managed to stay friends throughout the process. As our reward, we are now the proud authors of a reference book that we expect will be of use and interest to an eclectic readership.

Alice Calaprice is a renowned authority on Albert Einstein and the author of several popular books on Einstein, including The Ultimate Quotable Einstein (Princeton).

#ThanksEinstein image courtesy of the official Albert Einstein Facebook page.

#ThanksEinstein: J.P. Ostriker on Einstein and the wonder of pure thought

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Questions with No Reply

J. P. Ostriker

J.P. Ostriker is an astrophysicist and the co-author of Heart of Darkness, which tells the saga of humankind’s quest to unravel the deepest secrets of the universe: dark matter and dark energy. Here is his story about how an Einstein thought experiment he encountered as a teenager changed his life.

When I was a high school student I drove my teachers crazy with incessant and insatiable curiosity about the natural world. Next to our pictures in the yearbook, one of the teachers had added a line for each student and for me it was “I thought of questions that have no reply.”

And for the questions that I had that my teachers could not or would not answer, I went to books. Einstein wrote several of these that were accessible to high school students, and they fascinated me. I remember a “thought experiment” presented in one of them: A scientist sets up an exquisite laboratory on a train and tests both Newton’s laws of mechanics and Maxwell’s laws of electricity and magnetism. And, hypothetically, one finds that both are correct to arbitrary precision.

train image, copyright: phildaintThen the train begins to move and E shows that, since the laws transform differently with the velocity of the observer, they can no longer both be true! Therefore one (or both) theories must be false.

This amazed me. No experiment was necessary. Pure thought was all that was needed and any high school student who thought about it could have come to the same conclusion as Einstein, and could have invented special relativity to solve the problem! I thought that this was wonderful, truly wonderful. I resolved that I would pursue physics and think about simple and fundamental matters. It looked easy.

Well, needless to say it was not always easy, but it has always been fun. I’m thankful I had access to Einstein’s popular books when I was a teenager with more questions than answers.

Jeremiah P. Ostriker is professor of astrophysical sciences at Princeton University. He is author, with Simon Mitton, of Heart of Darkness: Unraveling the Mysteries of the Invisible Universe. His books include Formation of Structure in the Universe and Unsolved Problems in Astrophysics (Princeton).


Train tracks image from Shutterstock, copyright: phildaint

#ThanksEinstein: Katherine Freese on how relativity rejuvenated her career

Thanks Einstein Meme 3Under the Spell of Relativity

By Katherine Freese

Katherine Freese is director of Nordita, the Nordic Institute for Theoretical Physics, in Stockholm, and author of The Cosmic Cocktail, which tells of the epic quest to solve one of the most compelling enigmas of modern science—what is the universe made of? This is the story of how one of today’s foremost pioneers in the study of dark matter came back from the brink of burnout because of Relativity.

My career choice was hugely influenced by the work of Albert Einstein. I chose a career in physics precisely because I was inspired by his theories of relativity. My first exposure to physics was at Exeter Summer School in New Hampshire when I was fifteen years old. I went there after my junior year in high school because, frankly, I enjoyed learning and would otherwise have been bored over the long summer. I took an introductory course in physics and have to admit that, at first, I was a bit intimidated. But I got into it quickly and was gratified to discover that I did really well. The course was inspiring, and my teacher Mr. Dudley probably has no idea what an impact he had on me.

It was when the summer course turned to Special Relativity that I became really excited. What a bizarre and fascinating subject! To begin with, the idea that there is no absolute reference frame was an eye-opener. I later tried to explain this to friends, but they persisted in arguing that the Earth really does provide a special reference frame, world freeseat least for humans, so we should just compute everything from our own point of view.

Strange paradoxes arise when one makes one simple postulate, that the speed of light is the same in every reference frame. Two observers moving with relativistic speeds (relative to one another) measure completely different things. Clocks measure different times, and rulers measure different lengths. The shortest time is measured in the reference frame where the event takes place, and in every other frame time appears dilated. So an astronaut, who goes off into space and eventually returns, ages more slowly than the rest of us. There can be time travel! In the sense that the astronaut can come back to the Earth at an arbitrarily distant point in the future…if she can tolerate traveling at those speeds. Recently I met quite a few astronauts in Stockholm at the Congress of the Association of Space Explorers. They are amazing people. I was invited to give a 20 minute talk on “What we know about the Universe today.” A tall order in front of these folks. Can you guess what I talked about? Cosmology, beginning with Einstein’s relativity, of course.

These exciting things I learned when I was 15 made me determined to learn more physics, and I ended up majoring in physics in college. I went very young, at 16, and graduated with a bachelor’s degree in physics from Princeton University at the age of 20. It was really hard, I was burning out quickly, and at that point I wasn’t sure I wanted to continue. Chapter One of The Cosmic Cocktail, the book that was published by Princeton University Press just over a year ago, describes what happened next. I decided to take some time off from school. With my best friend, I went off to Tokyo to teach English and ended up serving drinks in bars for a giant salary. (I finally surpassed it a few years ago as a Full Professor.) A year and a half later, I went to Korea to renew my visa. While I was traveling around Pusang, my stomach, or so I thought, started to hurt. When I returned to Tokyo I was walking around doubled over with pain. Indeed it turned out to be appendicitis. I went to the Catholic Hospital, run by English nuns, and had my appendix removed.

While I was lying in the hospital bed, I read the only book I had brought with me, Spacetime Physics by Taylor and Wheeler. It is a book about Einstein’s special relativity. The book is beautifully written and only requires simple knowledge of forces, energy, and so on, and I loved it. The minute I got out of the hospital, I flew back to the US, reinvigorated by the desire to study physics. I contacted Columbia University, which had previously accepted me, and they let me in at a moment’s notice. I was lucky they did.

Einstein’s influence persisted. Two years into my graduate program at Columbia University, I went to Fermilab, the particle physics accelerator outside of Chicago, to work in experimental high energy physics. However, I also took a class in cosmology at the University of Chicago twice a week, out of curiosity. Plus, it took me into the city of Chicago. Fermilab is on a farm an hour west and has buffalo roaming around. The professor who taught the course, David Schramm, was a giant both physically and mentally, and one of the founders of the field of astroparticle physics, where the smallest particles explain the properties of the largest galaxies. We nicknamed him “Schrammbo.” (If you want to know more about him, you’ll have to read my book.) In that course, Einstein’s equations were applied to the Universe as a whole. Wow. I stopped showing up in the lab and instead sat in my housing at Fermilab and read about general relativity, this time at a graduate level framed by far deeper mathematics. Again, it was a turning point. I transferred to the University of Chicago to get my PhD with David Schramm in the field of cosmology.

In human history, every culture has had creation myths. In the past 100 years we have developed our own, the Big Bang. The difference is that the Hot Big Bang is right! The achievements over the past century in the field of cosmology are breakthroughs for all of mankind. We understand everything about our observable Universe all the way out to the farthest distant that light could have traveled to us in the age of the Universe (anything farther out could not have impacted us because the information could not travel in excess of the speed of light).

Now I’m a professional. I work with Einstein’s equations or their immediate consequences every day. I’m a theorist. I invent things and hope they turn out to match reality. All my work lies within the framework of modern cosmology, which began with Einstein’s work in relativity in 1915. What a brilliant man he was! Ever since I learned about relativity I’ve been under its spell, and I still am.

Katherine Freese is director of Nordita, the Nordic Institute for Theoretical Physics, in Stockholm, and professor of physics at the University of Michigan. She is the author of The Cosmic Cocktail.

#ThanksEinstein image courtesy of the official Albert Einstein Facebook page.

Feynman on the historic debate between Einstein & Bohr

The golden age of quantum theory put many of the greatest minds of the 20th century in contact with some of the most significant scientific and philosophical questions of their era. But it also put these minds in contact with one another in ways that have themselves been a source of curiosity and ongoing scientific debate.

Richard Feynman and Albert Einstein, two towering geniuses of their time, were both as revered for their scientific contributions as they were beloved for their bursts of wisdom on a wide range of subjects. It’s hard not to wonder just what these men thought of one another. Princeton University Press, which published The Ultimate Quotable Einstein in 2010 publishes The Quotable Feynman this fall. The book includes reflections by Feynman on Einstein, from his memorable mannerisms to his contributions to some of the most heated debates in 20th century science.Feynman quote

Perhaps because of the gap between their career high points, (Einstein died in 1955; Feynman didn’t receive his Nobel Prize until 1965), there are no verified quotes where Einstein alludes to Feynman or his expansive body of work. But Feynman had made observations on the older physicist, several of which revolve around Einstein’s famous 1927 public debate with Niels Bohr on the correctness of  quantum mechanics. Central to the debate was this question: Were electrons, light, and similar entities waves or particles? In some experiments they behaved like the former, and in others, the latter.

In an attempt to resolve the contradictory observations, Einstein proposed a series of “thought experiments”, which Bohr responded to. Bohr essentially took the stance that the very act of measuring alters reality, whereas Einstein insisted that reality exists, independent of the act of measurement. Key to the philosophy of science, the dispute between the two giants is detailed by Bohr in “Discussions with Einstein on Epistemological Problems in Atomic Physics”. Richard Feynman is quoted as commenting on the debate:Feynman quote 2

An Einstein Encyclopedia contains a section on the Einstein-Bohr debates, as well as a wealth of other information on Einstein’s career, family, friends. There is an entire section dedicated to righting the various misconceptions that swirl around the man, and another on his romantic interests (actual, probable, and possible).

In spite of their differences, Bohr and Einstein were friends and shared great respect for each others’ work. Until Einstein’s death 3 decades later, they continued their debates, which became, in essence, a debate about the nature of reality itself.  feynman quote 3

Check out other new Einstein publications this fall, including:

An Einstein Encyclopedia
The Road to Relativity

Wobbly table? Applied math can fix that

We are excited to be running a series of posts on applied mathematics by Nicholas Higham over the next few weeks. Higham is editor of The Princeton Companion to Applied Mathematics, new this month. Read his popular first post on color in mathematics here.

In The Princeton Companion to Applied Mathematics (page 50) I mention that a four-legged table provides an example of an ill-posed problem. If we take a table having four legs of equal length lying on a flat surface and shorten one leg by an arbitrarily small amount then the weight supported by that leg will jump from one quarter of the total weight to zero.


A table with one leg shorter than the others wobbles, as may one sitting on an uneven floor, and how to cure wobbly tables has been the subject of a number of papers over the years. The tongue-in cheek article

Hanspeter Kraft, The Wobbly Garden Table, Journal of Biological Physics and Chemistry 1, 95-96, 2001

describes how an engineer, a physicist, and a mathematician would go about solving the problem. The engineer would invent an adjustable leg. The physicist would submit a research proposal to tackle the more general problem of “the stability of multiply-legged objects on rough surfaces”. The mathematician would construct an argument based on the intermediate value theorem to show that stability can be restored with a suitable rotation of no more than 90 degrees. This argument has been discussed by several authors, but turning it into a mathematically precise statement with appropriate assumptions on the table and the ground on which it rests is not easy.

The two most recent contributions to this topic that I am aware of are:

A. Martin, On the Stability of Four-Legged Tables, Physics Letters A, 360, 495-500, 2007

Bill Baritompa, Rainer Löwen, Burkard Polster, and Marty Ross, Mathematical Table Turning Revisited, arXiv:math/0511490v1, 17 pp., 2008

In the latter paper it is shown that if the ground on which a rectangular table rests slopes by less than 35.36 degrees and the legs of the table are at least half as long as its diagonals then the rotation trick works.

For more insight into this problem you may like to watch the video below in which Matthias Kreck explains the problem with the aid of some excellent animations.

Introducing the new video trailer for The Quotable Feynman

Nobel Prize-winning physicist Richard P. Feynman (1918–88) is widely known for his scientific genius. But during his life, he became as famous for the wit, wisdom, and lucidity of his popular lectures and writings as for his fundamental contributions to physics. We are pleased to present the new video trailer for The Quotable Feynman, including approximately 500 quotations carefully selected by his daughter, Michelle Feynman, from his spoken and written legacy:

Check out chapter one here.





Washington Post highlights historic clash between Einstein and Bergson on the nature of time

2015_Einstein_bannerWith the 100th anniversary of the general theory of relativity coming up in November, Einstein is popping up everywhere. Yesterday’s Washington Post ran a terrific feature on Einstein books, including three of our own: Hanoch Gutfreund and Jürgen Renn’s The Road to Relativity, Einstein’s Relativity: The Special and the General Theory, and Jimena Canales’s The Physicist and the Philosopher.

One of the most fascinating chapters of Einstein’s public life revolves around an encounter he had with Henri Bergson, the renowned philosopher, on April 6, 1922, in Paris. It was on this day that Einstein and Bergson publicly debated the nature of time, touching off a clash of worldviews between science and the humanities that persists today. The philosopher Bergson argued that time was not merely mechanical, and should be seen in terms of lived experience; Einstein dismissed Bergson’s psychological notions as irreconcilable with the realities of physics. The Physicist and the Philosopher tells the remarkable story of how this explosive debate between two famous thinkers created intellectual rifts and revolutionized an entire generation’s understanding of time.

Nancy Szokan’s piece in Washington Post recounts the dramatic collision:

In The Physicist and the Philosopher, Canales recounts how Bergson challenged Einstein’s theories, arguing that time is not a fourth dimension definable by scientists but a ‘vital impulse,’ the source of creativity. It was an incendiary topic at the time, and it shaped a split between science and humanities that persisted for decades—though Einstein was generally seen as the winner and Bergson is all but forgotten.

Bergson and Einstein, toward the end of their lives, each reflected on his rival’s legacy and dedication to the pursuit of truth: Bergson during the Nazi occupation of Paris and Einstein in the wake of the first hydrogen bomb. Referencing Einstein’s quest for scientific truth, Hanoch Gutfreund recently had an article in the Huffington Post on how Einstein helped shape the Hebrew University of Jerusalem (home of the Albert Einstein Archives online):

On the occasion of the opening of the university, Albert Einstein published a manifesto “The Mission of our University”, which generated interest and excitement in the entire Jewish and academic worlds.

It states: “The opening of our Hebrew University on Mount Scopus, at Jerusalem, is an event which should not only fill us with just pride, but should also inspire us to serious reflection. … A University is a place where the universality of human spirit manifests itself. Science and investigation recognize as their aim the truth only.”

Read the rest here.

November’s big anniversary serves as a reminder of the enduring commitment to scientific investigation that continues at The Hebrew University and centers of learning all over the world today.

Read sample chapters of The Physicist and the Philosopher here, The Road to Relativity here, and Relativity here.

You can find information on the Digital Einstein Papers, an open access site for The Collected Papers of Albert Einstein, comprising more than 30,000 unique documents here.

Win a copy of THE ROAD TO RELATIVITY over on the official Einstein Facebook page!

Head on over to the official Facebook page of Albert Einstein to enter to win a copy of The Road to Relativity.

The contest starts today and will run from July 22nd at 11 AM ET until Wednesday, August 5th at 10:59 AM ET.

Einstein Book Contest Flyer 2

To celebrate the 100th anniversary of Albert Einstein’s theory of general relativity, Princeton University Press launches books by Hanoch Gutfreund and Jürgen Renn

The Road to RelativityOn July 15th, Princeton University Press proudly launched two books by Professor Hanoch Gutfreund and Jürgen Renn, Relativity and The Road to Relativity, at the 14th Marcel Grossman meeting on relativistic physics in Rome.

The two books are being published to celebrate the 100th anniversary of Albert Einstein’s formulation of the theory of general relativity in 1915, and so it was fitting to launch them at a conference that demonstrates the ongoing influence of Einstein’s theory on cutting edge work on black holes, pulsars, quantum gravity, and other areas fundamental to our understanding of the universe.

The launch took place at the Besso Foundation, the family home of Albert Einstein’s friend and colleague, Michele Besso, during an exhibition, organized by Professor Gutfreund, of original Einstein letters and notebooks from the Albert Einstein Archives at the Hebrew University in Jerusalem.

relativity jacketMore than 150 distinguished physicists and invited guests, including the Chief Rabbi of Rome, Riccardo di Segni, and members of the Besso and Grossman families, listened to Professor Gutfreund and Professor Renn provide a compelling overview of their research and of the new insights it has brought to the history of the development of general relativity. Professor Gutfreund stressed the fundamental insights into Einstein’s work provided by the rich Archives in Jerusalem, while Renn dismissed the notion of Albert Einstein as an isolated and idiosyncratic genius, stressing his network of collaborators and colleagues, including Besso.


Renn and Gutfreund

Professor Hanoch Gutfreund and Jürgen Renn at the book launch in Rome

Photo from Renn and Gutfreund launch

Launch for Relativity and The Road to Relativity, at the 14th Marcel Grossman meeting on relativistic physics in Rome