Albert Einstein
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Albert Einstein ( ; ; 14 March 1879 – 18 April 1955) was a German-born theoretical physicist who is widely held as one of the most influential
scientists A scientist is a person who conducts scientific research to advance knowledge in an area of the natural sciences. In classical antiquity, there was no real ancient analog of a modern scientist. Instead, philosophers engaged in the philosophica ...
. Best known for developing the
theory of relativity The theory of relativity usually encompasses two interrelated theories by Albert Einstein: special relativity and general relativity, proposed and published in 1905 and 1915, respectively. Special relativity applies to all physical phenomena in ...
, Einstein also made important contributions to
quantum mechanics Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, ...
. His
mass–energy equivalence In physics, mass–energy equivalence is the relationship between mass and energy in a system's rest frame, where the two quantities differ only by a multiplicative constant and the units of measurement. The principle is described by the physicis ...
formula , which arises from relativity theory, has been called "the world's most famous equation". He received the 1921
Nobel Prize in Physics ) , image = Nobel Prize.png , alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then " ...
"for his services to theoretical physics, and especially for his discovery of the law of the photoelectric effect", a pivotal step in the development of quantum theory. His intellectual achievements and originality have made the word ''Einstein'' broadly synonymous with ''genius''. Born in the
German Empire The German Empire (),Herbert Tuttle wrote in September 1881 that the term "Reich" does not literally connote an empire as has been commonly assumed by English-speaking people. The term literally denotes an empire – particularly a hereditary ...
, Einstein moved to Switzerland in 1895, forsaking his German citizenship (as a subject of the
Kingdom of Württemberg The Kingdom of Württemberg (german: Königreich Württemberg ) was a German state that existed from 1805 to 1918, located within the area that is now Baden-Württemberg. The kingdom was a continuation of the Duchy of Württemberg, which exist ...
) the following year. In 1897, at the age of seventeen, he enrolled in the mathematics and physics teaching diploma program at the Swiss
federal polytechnic school (colloquially) , former_name = eidgenössische polytechnische Schule , image = ETHZ.JPG , image_size = , established = , type = Public , budget = CHF 1.896 billion (2021) , rector = Günther Dissertori , president = Joël Mesot , ac ...
in
Zürich Zürich () is the list of cities in Switzerland, largest city in Switzerland and the capital of the canton of Zürich. It is located in north-central Switzerland, at the northwestern tip of Lake Zürich. As of January 2020, the municipality has 43 ...
, graduating in 1900. In 1901, he acquired Swiss citizenship, which he kept for the rest of his life. In 1903, he secured a permanent position at the Swiss Patent Office in Bern. In 1905, he submitted a successful PhD dissertation to the University of Zurich. In 1914, he moved to
Berlin Berlin ( , ) is the capital and largest city of Germany by both area and population. Its 3.7 million inhabitants make it the European Union's most populous city, according to population within city limits. One of Germany's sixteen constitue ...
in order to join the Prussian Academy of Sciences and the
Humboldt University of Berlin Humboldt-Universität zu Berlin (german: Humboldt-Universität zu Berlin, abbreviated HU Berlin) is a German public research university in the central borough of Mitte in Berlin. It was established by Frederick William III on the initiative o ...
. In 1917, he became director of the
Kaiser Wilhelm Institute for Physics The Kaiser Wilhelm Society for the Advancement of Science (German language, German: ''Kaiser-Wilhelm-Gesellschaft zur Förderung der Wissenschaften'') was a German scientific institution established in the German Empire in 1911. Its functions we ...
; he also became a German citizen again, this time as a subject of the
Kingdom of Prussia The Kingdom of Prussia (german: Königreich Preußen, ) was a German kingdom that constituted the state of Prussia between 1701 and 1918.Marriott, J. A. R., and Charles Grant Robertson. ''The Evolution of Prussia, the Making of an Empire''. Re ...
. In 1933, while Einstein was visiting the United States, Adolf Hitler came to power in Germany. Horrified by the
Nazi Nazism ( ; german: Nazismus), the common name in English for National Socialism (german: Nationalsozialismus, ), is the far-right totalitarian political ideology and practices associated with Adolf Hitler and the Nazi Party (NSDAP) in ...
war of extermination A war of annihilation (german: Vernichtungskrieg) or war of extermination is a type of war in which the goal is the complete annihilation of a State (polity), state, a Ethnic group, people or an ethnic minority through genocide or through the de ...
against his fellow Jews, Einstein decided to remain in the US, and was granted
American citizen Citizenship of the United States is a legal status that entails Americans with specific rights, duties, protections, and benefits in the United States. It serves as a foundation of fundamental rights derived from and protected by the Constituti ...
ship in 1940. On the eve of
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
, he endorsed a letter to President
Franklin D. Roosevelt Franklin Delano Roosevelt (; ; January 30, 1882April 12, 1945), often referred to by his initials FDR, was an American politician and attorney who served as the 32nd president of the United States from 1933 until his death in 1945. As the ...
alerting him to the potential
German nuclear weapons program The Uranverein ( en, "Uranium Club") or Uranprojekt ( en, "Uranium Project") was the name given to the project in Germany to research nuclear technology, including nuclear weapons and nuclear reactors, during World War II. It went through seve ...
and recommended that the US begin similar research. Einstein supported the
Allies An alliance is a relationship among people, groups, or states that have joined together for mutual benefit or to achieve some common purpose, whether or not explicit agreement has been worked out among them. Members of an alliance are called ...
but generally viewed the idea of
nuclear weapon A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions ( thermonuclear bomb), producing a nuclear explosion. Both bom ...
s with great dismay. Einstein's work is also known for its influence on the
philosophy of science Philosophy of science is a branch of philosophy concerned with the foundations, methods, and implications of science. The central questions of this study concern what qualifies as science, the reliability of scientific theories, and the ultim ...
. In 1905, he published four groundbreaking papers, sometimes described as his '' annus mirabilis'' (miracle year). These papers outlined a theory of the photoelectric effect, explained Brownian motion, introduced his
special theory of relativity In physics, the special theory of relativity, or special relativity for short, is a scientific theory regarding the relationship between Spacetime, space and time. In Albert Einstein's original treatment, the theory is based on two Postulates of ...
—a theory which addressed the inability of
classical mechanics Classical mechanics is a physical theory describing the motion of macroscopic objects, from projectiles to parts of machinery, and astronomical objects, such as spacecraft, planets, stars, and galaxies. For objects governed by classical ...
to account satisfactorily for the behavior of the
electromagnetic field An electromagnetic field (also EM field or EMF) is a classical (i.e. non-quantum) field produced by (stationary or moving) electric charges. It is the field described by classical electrodynamics (a classical field theory) and is the classical c ...
—and demonstrated that if the special theory is correct, mass and energy are equivalent to each other. In 1915, he proposed a general theory of relativity that extended his system of mechanics to incorporate
gravitation In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the stron ...
. A cosmological paper that he published the following year laid out the implications of general relativity for the modeling of the structure and evolution of the
universe The universe is all of space and time and their contents, including planets, stars, galaxies, and all other forms of matter and energy. The Big Bang theory is the prevailing cosmological description of the development of the universe. Acc ...
as a whole. In the middle part of his career, Einstein made important contributions to
statistical mechanics In physics, statistical mechanics is a mathematical framework that applies statistical methods and probability theory to large assemblies of microscopic entities. It does not assume or postulate any natural laws, but explains the macroscopic be ...
and quantum theory. Especially notable was his work on the quantum physics of
radiation In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium. This includes: * ''electromagnetic radiation'', such as radio waves, microwaves, infrared, visi ...
, in which light consists of particles, subsequently called
photon A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are massless, so they always ...
s. With the
India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
n physicist
Satyendra Nath Bose Satyendra Nath Bose (; 1 January 1894 – 4 February 1974) was a Bengali mathematician and physicist specializing in theoretical physics. He is best known for his work on quantum mechanics in the early 1920s, in developing the foundation for ...
, he laid the groundwork for Bose-Einstein statistics. For much of the last phase of his academic life, Einstein worked on two endeavors that proved ultimately unsuccessful. First, he advocated against quantum theory's introduction of fundamental randomness into science's picture of the world, objecting that "God does not play dice". Second, he attempted to devise a
unified field theory In physics, a unified field theory (UFT) is a type of field theory that allows all that is usually thought of as fundamental forces and elementary particles to be written in terms of a pair of physical and virtual fields. According to the modern ...
by generalizing his geometric theory of gravitation to include
electromagnetism In physics, electromagnetism is an interaction that occurs between particles with electric charge. It is the second-strongest of the four fundamental interactions, after the strong force, and it is the dominant force in the interactions of a ...
too. As a result, he became increasingly isolated from the mainstream
modern physics Modern physics is a branch of physics that developed in the early 20th century and onward or branches greatly influenced by early 20th century physics. Notable branches of modern physics include quantum mechanics, special relativity and general ...
. In a 1999 poll of 130 leading physicists worldwide by the British journal '' Physics World'', Einstein was ranked the greatest physicist of all time.


Life and career


Childhood, youth and education

Albert Einstein was born in Ulm, in the Kingdom of Württemberg in the German Empire, on 14 March 1879. His parents, secular
Ashkenazi Jews Ashkenazi Jews ( ; he, יְהוּדֵי אַשְׁכְּנַז, translit=Yehudei Ashkenaz, ; yi, אַשכּנזישע ייִדן, Ashkenazishe Yidn), also known as Ashkenazic Jews or ''Ashkenazim'',, Ashkenazi Hebrew pronunciation: , singu ...
, were
Hermann Einstein The Einstein family is the family of physicist Albert Einstein (1879–1955). Einstein's great-great-great-great-grandfather, Jakob Weil, was his oldest recorded relative, born in the late 17th century, and the family continues to this day. Al ...
, a salesman and engineer, and Pauline Koch. In 1880, the family moved to
Munich Munich ( ; german: München ; bar, Minga ) is the capital and most populous city of the States of Germany, German state of Bavaria. With a population of 1,558,395 inhabitants as of 31 July 2020, it is the List of cities in Germany by popu ...
's borough of Ludwigsvorstadt-Isarvorstadt, where Einstein's father and his uncle Jakob founded Elektrotechnische Fabrik J. Einstein & Cie, a company that manufactured electrical equipment based on
direct current Direct current (DC) is one-directional flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor such as a wire, but can also flow through semiconductors, insulators, or even ...
. Albert attended St. Peter‘s Catholic elementary school in Munich from the age of five. When he was eight, he was transferred to the
Luitpold Gymnasium The Luitpold-Gymnasium Note that "Gymnasium" is German for high school, see Gymnasium and False friend. is a secondary school in Munich, Germany. It is located in the Lehel city district, close to Munich's Old Town, and has a long tradition. Est ...
, where he received advanced primary and then secondary school education. In 1894, Hermann and Jakob's company tendered for a contract to install electric lighting in Munich, but without success—they lacked the capital that would have been required to update their technology from direct current to the more efficient,
alternating current Alternating current (AC) is an electric current which periodically reverses direction and changes its magnitude continuously with time in contrast to direct current (DC) which flows only in one direction. Alternating current is the form in whic ...
alternative. The failure of their bid forced them to sell their Munich factory and search for new opportunities elsewhere. The Einstein family moved to Italy, first to
Milan Milan ( , , Lombard: ; it, Milano ) is a city in northern Italy, capital of Lombardy, and the second-most populous city proper in Italy after Rome. The city proper has a population of about 1.4 million, while its metropolitan city h ...
and a few months later to
Pavia Pavia (, , , ; la, Ticinum; Medieval Latin: ) is a town and comune of south-western Lombardy in northern Italy, south of Milan on the lower Ticino river near its confluence with the Po. It has a population of c. 73,086. The city was the capit ...
, where they settled in
Palazzo Cornazzani Palazzo Cornazzani is a palace in Pavia, in Lombardy, where, between 1895 and 1896, Albert Einstein lived. History The palace belonged to the noble Cornazzani family and was built in the 15th century, incorporating the remains of previous bu ...
. Einstein, then fifteen, stayed behind in Munich in order to finish his schooling. His father wanted him to study
electrical engineering Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems which use electricity, electronics, and electromagnetism. It emerged as an identifiable occupation in the l ...
, but he was a fractious pupil who found the Gymnasium's regimen and teaching methods far from congenial. He later wrote that the school's policy of strict rote learning was harmful to creativity. At the end of December 1894, a letter from a doctor persuaded the Luitpold's authorities to release him from its care, and he joined his family in Pavia. While in Italy as a teenager, he wrote an essay entitled "On the Investigation of the State of the
Ether In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again be c ...
in a Magnetic Field". Einstein excelled at physics and mathematics from an early age, and soon acquired the mathematical expertise normally only found in a child several years his senior. He began teaching himself algebra, calculus and Euclidean geometry when he was twelve; he made such rapid progress that he discovered an original proof of the
Pythagorean theorem In mathematics, the Pythagorean theorem or Pythagoras' theorem is a fundamental relation in Euclidean geometry between the three sides of a right triangle. It states that the area of the square whose side is the hypotenuse (the side opposite t ...
before his thirteenth birthday. A family tutor,
Max Talmud Max Talmey (1869–1941) was an American ophthalmologist of Jewish- Lithuanian descent, best known as Albert Einstein's tutor who introduced him to fields and books on natural science and philosophy, his success in treating cataracts, and his wor ...
, said that only a short time after he had given the twelve year old Einstein a geometry textbook, the boy "had worked through the whole book. He thereupon devoted himself to higher mathematics ... Soon the flight of his mathematical genius was so high I could not follow." Einstein recorded that he had "mastered
integral In mathematics Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented i ...
and
differential calculus In mathematics, differential calculus is a subfield of calculus that studies the rates at which quantities change. It is one of the two traditional divisions of calculus, the other being integral calculus—the study of the area beneath a curve. ...
" while still just fourteen. His love of algebra and geometry was so great that at twelve, he was already confident that nature could be understood as a "mathematical structure". At thirteen, when his range of enthusiasms had broadened to include music and philosophy, Talmud introduced Einstein to Kant's '' Critique of Pure Reason''. Kant became his favorite philosopher; according to Talmud, "At the time he was still a child, only thirteen years old, yet Kant's works, incomprehensible to ordinary mortals, seemed to be clear to him." In 1895, at the age of sixteen, Einstein sat the entrance examination for the
federal polytechnic school (colloquially) , former_name = eidgenössische polytechnische Schule , image = ETHZ.JPG , image_size = , established = , type = Public , budget = CHF 1.896 billion (2021) , rector = Günther Dissertori , president = Joël Mesot , ac ...
(later the Eidgenössische Technische Hochschule, ETH) in Zürich, Switzerland. He failed to reach the required standard in the general part of the test, but performed with distinction in physics and mathematics. On the advice of the polytechnic's principal, he completed his secondary education at the Argovian cantonal school (a ''gymnasium'') in
Aarau Aarau (, ) is a List of towns in Switzerland, town, a Municipalities of Switzerland, municipality, and the capital of the northern Swiss Cantons of Switzerland, canton of Aargau. The List of towns in Switzerland, town is also the capital of the dis ...
, Switzerland, graduating in 1896. ref for:
Old Cantonal School Aarau The old cantonal school of Aarau (in German: AKSA, Alte Kantonsschule Aarau or Alte Kanti) was founded in 1802 and is the oldest non-church secondary school in Switzerland. History From 1802 to 1896, the cantonal school was housed in what i ...
While lodging in Aarau with the family of
Jost Winteler Jost Winteler (21 November 1846 - 23 February 1929) was a Swiss professor of Greek and history at the Kantonsschule Aarau (today called the Old Cantonal School Aarau), a linguist, a "noted" philologist, an ornithologist, a journalist, and a pu ...
, he fell in love with Winteler's daughter, Marie. (His sister, Maja, later married Winteler's son Paul.) In January 1896, with his father's approval, Einstein renounced his citizenship of the German Kingdom of Württemberg in order to avoid conscription into military service. The '' Matura'' (graduation for the successful completion of higher secondary schooling), awarded to him in September 1896, acknowledged him to have performed well across most of the curriculum, allotting him a top grade of 6 for history, physics, algebra, geometry, and descriptive geometry. At seventeen, he enrolled in the four-year mathematics and physics teaching diploma program at the federal polytechnic school. Marie Winteler, a year older than him, took up a teaching post in Olsberg, Switzerland. The five other polytechnic school freshmen following the same course as Einstein included just one woman, a twenty year old
Serbian Serbian may refer to: * someone or something related to Serbia, a country in Southeastern Europe * someone or something related to the Serbs, a South Slavic people * Serbian language * Serbian names See also

* * * Old Serbian (disambiguat ...
,
Mileva Marić Mileva Marić ( sr-cyr, Милева Марић; 19 December 1875 – 4 August 1948), sometimes called Mileva Marić-Einstein ( sr-cyr, Милева Марић-Ајнштајн, Mileva Marić-Ajnštajn), was a Serbian physicist and mathematicia ...
. Over the next few years, the pair spent many hours discussing their shared interests and learning about topics in physics that the polytechnic school's lectures did not cover. In his letters to Marić, Einstein confessed that exploring science with her by his side was much more enjoyable than reading a textbook in solitude. Eventually the two students became not only friends but also lovers. Historians of physics are divided on the question of the extent to which Marić contributed to the insights of Einstein's ''annus mirabilis'' publications. There is at least some evidence that he was influenced by her scientific ideas, but there are scholars who doubt whether her impact on his thought was of any great significance at all.


Marriages, relationships and children

Correspondence between Einstein and Marić, discovered and published in 1987, revealed that in early 1902, while Marić was visiting her parents in
Novi Sad Novi Sad ( sr-Cyrl, Нови Сад, ; hu, Újvidék, ; german: Neusatz; see below for other names) is the second largest city in Serbia and the capital of the autonomous province of Vojvodina. It is located in the southern portion of the Pan ...
, she gave birth to a daughter,
Lieserl "Lieserl" is a science fiction short story by British writer Stephen Baxter, originally published in '' Interzone'' in 1993. Appearing also in his anthology ''Vacuum Diagrams'', it represents a small, but integral part of the novel '' Ring''. ...
. When Marić returned to Switzerland it was without the child, whose fate is uncertain. A letter of Einstein's that he wrote in September 1903 suggests that the girl was either given up for adoption or died of
scarlet fever Scarlet fever, also known as Scarlatina, is an infectious disease caused by ''Streptococcus pyogenes'' a Group A streptococcus (GAS). The infection is a type of Group A streptococcal infection (Group A strep). It most commonly affects childr ...
in infancy. Einstein and Marić married in January 1903. In May 1904, their son Hans Albert was born in
Bern german: Berner(in)french: Bernois(e) it, bernese , neighboring_municipalities = Bremgarten bei Bern, Frauenkappelen, Ittigen, Kirchlindach, Köniz, Mühleberg, Muri bei Bern, Neuenegg, Ostermundigen, Wohlen bei Bern, Zollikofen , website ...
, Switzerland. Their son
Eduard Eduard Model Accessories is a Czech manufacturer of plastic models and finescale model accessories. Formed in 1989 in the city of Most, Eduard began in a rented cellar as a manufacturer of photoetched brass model components. Following the succ ...
was born in Zürich in July 1910. In letters that Einstein wrote to Marie Winteler in the months before Eduard's arrival, he described his love for his wife as "misguided" and mourned the "missed life" that he imagined he would have enjoyed if he had married Winteler instead: "I think of you in heartfelt love every spare minute and am so unhappy as only a man can be." In 1912, Einstein entered into a relationship with
Elsa Löwenthal Elsa Einstein (18 January 1876 – 20 December 1936) was the second wife and cousin of Albert Einstein. Their mothers were sisters, thus making them maternal first cousins. Further, their fathers were first cousins, making the couple paternal se ...
, who was both his first cousin on his mother's side and his second cousin on his father's. When Marić learned of his infidelity soon after moving to Berlin with him in April 1914, she returned to Zürich, taking Hans Albert and Eduard with her. Einstein and Marić were granted a divorce on 14 February 1919 on the grounds of having lived apart for five years. As part of the divorce settlement, Einstein agreed that if he were to win a Nobel Prize, he would give the money that he received to Marić; he won the prize two years later. Einstein married Löwenthal in 1919. In 1923, he began a relationship with a secretary named Betty Neumann, the niece of his close friend Hans Mühsam. Löwenthal nevertheless remained loyal to him, accompanying him when he emigrated to the United States in 1933. In 1935, she was diagnosed with heart and kidney problems. She died in December 1936. A volume of Einstein's letters released by
Hebrew University of Jerusalem The Hebrew University of Jerusalem (HUJI; he, הַאוּנִיבֶרְסִיטָה הַעִבְרִית בִּירוּשָׁלַיִם) is a public research university based in Jerusalem, Israel. Co-founded by Albert Einstein and Dr. Chaim Weiz ...
in 2006 added further names to the catalog of women with whom he was romantically involved. They included Margarete Lebach (a married Austrian), Estella Katzenellenbogen (the rich owner of a florist business), Toni Mendel (a wealthy Jewish widow) and Ethel Michanowski (a Berlin socialite), with whom he spent time and from whom he accepted gifts while married to Löwenthal. After being widowed, Einstein was briefly in a relationship with Margarita Konenkova, thought by some to be a Russian spy; her husband, the Russian sculptor
Sergei Konenkov Sergey Timofeyevich Konenkov (Сергей Тимофеевич Коненков) (also Sergei Konyonkov) (russian: Серге́й Тимофеевич Конёнков; – 9 December 1971) was a Russian and Soviet Union, Soviet sculptor. ...
, created the bronze bust of Einstein at the
Institute for Advanced Study The Institute for Advanced Study (IAS), located in Princeton, New Jersey, in the United States, is an independent center for theoretical research and intellectual inquiry. It has served as the academic home of internationally preeminent scholar ...
at Princeton. Following an episode of acute mental illness at about the age of twenty, Einstein's son Eduard was diagnosed with
schizophrenia Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social withdra ...
. He spent the remainder of his life either in the care of his mother or in temporary confinement in an asylum. After her death, he was committed permanently to
Burghölzli The ''Psychiatrische Universitätsklinik Zürich'' (Psychiatric University Hospital Zürich) is a psychiatric hospital in Switzerland. As a research hospital, it is associated with the University of Zürich. It is also called Burghölzli, after th ...
, the Psychiatric University Hospital in Zürich.


1902–1909: Assistant at the Swiss Patent Office

Einstein graduated from the federal polytechnic school in 1900, duly certified as competent to teach mathematics and physics. His successful acquisition of Swiss citizenship in February 1901 was not followed by the usual sequel of
conscription Conscription (also called the draft in the United States) is the state-mandated enlistment of people in a national service, mainly a military service. Conscription dates back to antiquity and it continues in some countries to the present day un ...
; the Swiss authorities deemed him medically unfit for military service. He found that Swiss schools too appeared to have no use for him, failing to offer him a teaching position despite the almost two years that he spent applying for one. Eventually it was with the help of
Marcel Grossmann Marcel Grossmann (April 9, 1878 – September 7, 1936) was a Swiss mathematician and a friend and classmate of Albert Einstein. Grossmann was a member of an old Swiss family from Zurich. His father managed a textile factory. He became a Profe ...
's father that he secured a post in
Bern german: Berner(in)french: Bernois(e) it, bernese , neighboring_municipalities = Bremgarten bei Bern, Frauenkappelen, Ittigen, Kirchlindach, Köniz, Mühleberg, Muri bei Bern, Neuenegg, Ostermundigen, Wohlen bei Bern, Zollikofen , website ...
at the Swiss Patent Office, as an assistant examiner – level III. Patent applications that landed on Einstein's desk for his evaluation included ideas for a gravel sorter and an electric typewriter. His employers were pleased enough with his work to make his position permanent in 1903, although they did not think that he should be promoted until he had "fully mastered machine technology". It is conceivable that his labors at the patent office had a bearing on his development of his special theory of relativity. He arrived at his revolutionary ideas about space, time and light through thought experiments about the transmission of signals and the synchronization of clocks, matters which also figured in some of the inventions submitted to him for assessment. In 1902, Einstein and some friends whom he had met in Bern formed a group that held regular meetings to discuss science and philosophy. Their choice of a name for their club, the Olympia Academy, was an ironic comment upon its far from Olympian status. Sometimes they were joined by Marić, who limited her participation in their proceedings to careful listening. The thinkers whose works they reflected upon included
Henri Poincaré Jules Henri Poincaré ( S: stress final syllable ; 29 April 1854 – 17 July 1912) was a French mathematician, theoretical physicist, engineer, and philosopher of science. He is often described as a polymath, and in mathematics as "The ...
,
Ernst Mach Ernst Waldfried Josef Wenzel Mach ( , ; 18 February 1838 – 19 February 1916) was a Moravian-born Austrian physicist and philosopher, who contributed to the physics of shock waves. The ratio of one's speed to that of sound is named the Mach ...
and
David Hume David Hume (; born David Home; 7 May 1711 NS (26 April 1711 OS) – 25 August 1776) Cranston, Maurice, and Thomas Edmund Jessop. 2020 999br>David Hume" ''Encyclopædia Britannica''. Retrieved 18 May 2020. was a Scottish Enlightenment philo ...
, all of whom significantly influenced Einstein's own subsequent ideas and beliefs.


1900–1905: First scientific papers

Einstein's first paper, "Folgerungen aus den Capillaritätserscheinungen" ("Conclusions drawn from the phenomena of capillarity"), in which he proposed a model of intermolecular attraction that he afterwards disavowed as worthless, was published in the journal '' Annalen der Physik'' in 1901. His 24-page doctoral dissertation also addressed a topic in molecular physics. Titled "Eine neue Bestimmung der Moleküldimensionen" ("A New Determination of Molecular Dimensions") and dedicated to his friend Marcel Grossman, it was completed on 30 April 1905 and approved by Professor
Alfred Kleiner Alfred Kleiner (24 April 1849 – 3 July 1916) was a Swiss physicist and Professor of Experimental Physics at the University of Zurich. He was Albert Einstein's doctoral advisor or ''Doktorvater.'' Initially Einstein's advisor was Heinrich F ...
of the University of Zurich three months later. (Einstein was formally awarded his PhD on 15 January 1906.) Four other pieces of work that Einstein completed in 1905— his famous papers on the photoelectric effect, Brownian motion, his
special theory of relativity In physics, the special theory of relativity, or special relativity for short, is a scientific theory regarding the relationship between Spacetime, space and time. In Albert Einstein's original treatment, the theory is based on two Postulates of ...
and the
equivalence of mass and energy Equivalence or Equivalent may refer to: Arts and entertainment *Album-equivalent unit, a measurement unit in the music industry *Equivalence class (music) *''Equivalent VIII'', or ''The Bricks'', a minimalist sculpture by Carl Andre *''Equivale ...
—have led to the year being celebrated as an ''annus mirabilis'' for physics akin to 1666 (the year in which
Isaac Newton Sir Isaac Newton (25 December 1642 – 20 March 1726/27) was an English mathematician, physicist, astronomer, alchemist, theologian, and author (described in his time as a "natural philosopher"), widely recognised as one of the grea ...
experienced his greatest epiphanies). The publications deeply impressed Einstein's contemporaries.


1908–1933: Early academic career

Einstein's sabbatical as a civil servant approached its end in 1908, when he secured a junior teaching position at the
University of Bern The University of Bern (german: Universität Bern, french: Université de Berne, la, Universitas Bernensis) is a university in the Switzerland, Swiss capital of Bern and was founded in 1834. It is regulated and financed by the Canton of Bern. It ...
. In 1909, a lecture on relativistic electrodynamics that he gave at the University of Zurich, much admired by Alfred Kleiner, led to Zürich's luring him away from Bern with a newly created associate professorship. Promotion to a full professorship followed in April 1911, when he accepted a chair at the German
Charles-Ferdinand University Charles University ( cs, Univerzita Karlova, UK; la, Universitas Carolina; german: Karls-Universität), also known as Charles University in Prague or historically as the University of Prague ( la, Universitas Pragensis, links=no), is the oldest an ...
in Prague, a move which required him to become an
Austrian Austrian may refer to: * Austrians, someone from Austria or of Austrian descent ** Someone who is considered an Austrian citizen, see Austrian nationality law * Austrian German dialect * Something associated with the country Austria, for example: ...
citizen of the
Austro-Hungarian Empire Austria-Hungary, often referred to as the Austro-Hungarian Empire,, the Dual Monarchy, or Austria, was a constitutional monarchy and great power in Central Europe between 1867 and 1918. It was formed with the Austro-Hungarian Compromise of ...
. His time in Prague saw him producing eleven research papers. In July 1912, he returned to his ''alma mater'', the
ETH Zurich (colloquially) , former_name = eidgenössische polytechnische Schule , image = ETHZ.JPG , image_size = , established = , type = Public , budget = CHF 1.896 billion (2021) , rector = Günther Dissertori , president = Joël Mesot , ac ...
, to take up a chair in theoretical physics. His teaching activities there centred on
thermodynamics Thermodynamics is a branch of physics that deals with heat, work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quantities is governed by the four laws of the ...
and analytical mechanics, and his research interests included the molecular theory of heat,
continuum mechanics Continuum mechanics is a branch of mechanics that deals with the mechanical behavior of materials modeled as a continuous mass rather than as discrete particles. The French mathematician Augustin-Louis Cauchy was the first to formulate such m ...
and the development of a relativistic theory of gravitation. In his work on the latter topic, he was assisted by his friend, Marcel Grossmann, whose knowledge of the kind of mathematics required was greater than his own. In the spring of 1913, two German visitors, Max Planck and
Walther Nernst Walther Hermann Nernst (; 25 June 1864 – 18 November 1941) was a German chemist known for his work in thermodynamics, physical chemistry, electrochemistry, and solid state physics. His formulation of the Nernst heat theorem helped pave the wa ...
, called upon Einstein in Zürich in the hope of persuading him to relocate to Berlin. They offered him membership of the Prussian Academy of Sciences, the directorship of the planned
Kaiser Wilhelm Institute for Physics The Kaiser Wilhelm Society for the Advancement of Science (German language, German: ''Kaiser-Wilhelm-Gesellschaft zur Förderung der Wissenschaften'') was a German scientific institution established in the German Empire in 1911. Its functions we ...
and a chair at the
Humboldt University of Berlin Humboldt-Universität zu Berlin (german: Humboldt-Universität zu Berlin, abbreviated HU Berlin) is a German public research university in the central borough of Mitte in Berlin. It was established by Frederick William III on the initiative o ...
that would allow him to pursue his research supported by a professorial salary but with no teaching duties to burden him. Their invitation was all the more appealing to him because Berlin happened to be the home of his latest girlfriend, Elsa Löwenthal. He duly joined the Academy on 24 July 1913, and moved into an apartment in the Berlin district of Dahlem on 1 April 1914. He was installed in his Humboldt University position shortly thereafter. The outbreak of the
First World War World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
in July 1914 marked the beginning of Einstein's gradual estrangement from the nation of his birth. When the "
Manifesto of the Ninety-Three The "Manifesto of the Ninety-Three" (originally "To the Civilized World" by "Professors of Germany") is a 4 October 1914 proclamation by 93 prominent Germans supporting Germany in the start of World War I. The Manifesto galvanized support for the w ...
" was published in October 1914—a document signed by a host of prominent German thinkers that justified Germany's belligerence—Einstein was one of the few German intellectuals to distance himself from it and sign the alternative, eirenic "
Manifesto to the Europeans The ″Manifesto to the Europeans″ (German: ''Aufruf an die Europäer'') was a pacifistic proclamation written in response to the Manifesto of the Ninety-Three that included as its authors, German astronomer, Wilhelm Julius Foerster, and German p ...
" instead. However, this expression of his doubts about German policy did not prevent him from being elected to a two-year term as president of the
German Physical Society The German Physical Society (German: , DPG) is the oldest organisation of physicists. The DPG's worldwide membership is cited as 60,547, as of 2019, making it the largest physics society in the world. It holds an annual conference () and multiple ...
in 1916. When the Kaiser Wilhelm Institute for Physics opened its doors the following year—its foundation delayed because of the war—Einstein was appointed its first director, just as Planck and Nernst had promised. Einstein was elected a Foreign Member of the
Royal Netherlands Academy of Arts and Sciences The Royal Netherlands Academy of Arts and Sciences ( nl, Koninklijke Nederlandse Akademie van Wetenschappen, abbreviated: KNAW) is an organization dedicated to the advancement of science and literature in the Netherlands. The academy is housed ...
in 1920, and a Foreign Member of the Royal Society in 1921. In 1922, he was awarded the 1921
Nobel Prize in Physics ) , image = Nobel Prize.png , alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then " ...
"for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect". At this point some physicists still regarded the general theory of relativity sceptically, and the Nobel citation displayed a degree of doubt even about the work on photoelectricity that it acknowledged: it did not assent to Einstein's notion of the particulate nature of light, which only won over the entire scientific community when
S. N. Bose Satyendra Nath Bose (; 1 January 1894 – 4 February 1974) was a Bengali mathematician and physicist specializing in theoretical physics. He is best known for his work on quantum mechanics in the early 1920s, in developing the foundation for ...
derived the
Planck spectrum A black body or blackbody is an idealized physical object, physical body that absorption (electromagnetic radiation), absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence (optics), angle of incidence. T ...
in 1924. That same year, Einstein was elected an International Honorary Member of the
American Academy of Arts and Sciences The American Academy of Arts and Sciences (abbreviation: AAA&S) is one of the oldest learned societies in the United States. It was founded in 1780 during the American Revolution by John Adams, John Hancock, James Bowdoin, Andrew Oliver, and ...
. Britain's closest equivalent of the Nobel award, the
Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...
's
Copley Medal The Copley Medal is an award given by the Royal Society, for "outstanding achievements in research in any branch of science". It alternates between the physical sciences or mathematics and the biological sciences. Given every year, the medal is t ...
, was not hung around Einstein's neck until 1925. He was elected an International Member of the
American Philosophical Society The American Philosophical Society (APS), founded in 1743 in Philadelphia, is a scholarly organization that promotes knowledge in the sciences and humanities through research, professional meetings, publications, library resources, and communit ...
in 1930. Einstein resigned from the Prussian Academy in March 1933. His accomplishments in Berlin had included the completion of the general theory of relativity, proving the Einstein–de Haas effect, contributing to the quantum theory of radiation, and the development of Bose–Einstein statistics.


1919: Putting general relativity to the test

In 1907, Einstein reached a milestone on his long journey from his special theory of relativity to a new idea of gravitation with the formulation of his
equivalence principle In the theory of general relativity, the equivalence principle is the equivalence of gravitational and inertial mass, and Albert Einstein's observation that the gravitational "force" as experienced locally while standing on a massive body (suc ...
, which asserts that an observer in an infinitesimally small box falling freely in a gravitational field would be unable to find any evidence that the field exists. In 1911, he used the principle to estimate the amount by which a ray of light from a distant star would be
bent Bent may refer to: Places * Bent, Iran, a city in Sistan and Baluchestan Province, Iran * Bent District, an administrative subdivision of Iran * Bent, Netherlands, a village in the municipality of Rijnwoude, the Netherlands * Bent County, Colo ...
by the gravitational pull of the Sun as it passed close to the Sun's
photosphere The photosphere is a star's outer shell from which light is radiated. The term itself is derived from Ancient Greek roots, φῶς, φωτός/''phos, photos'' meaning "light" and σφαῖρα/''sphaira'' meaning "sphere", in reference to it ...
(that is, the Sun's apparent surface). He reworked his calculation in 1913, having now found a way to model gravitation with the Riemann curvature tensor of a non-Euclidean four-dimensional
spacetime In physics, spacetime is a mathematical model that combines the three dimensions of space and one dimension of time into a single four-dimensional manifold. Spacetime diagrams can be used to visualize relativistic effects, such as why differen ...
. By the fall of 1915, his reimagining of the mathematics of gravitation in terms of Riemannian geometry was complete, and he applied his new theory not just to the behavior of the Sun as a gravitational lens but also to another astronomical phenomenon, the
precession of the perihelion of Mercury Tests of general relativity serve to establish observational evidence for the theory of general relativity. The first three tests, proposed by Albert Einstein in 1915, concerned the "anomalous" precession of the perihelion of Mercury, the bending ...
(a slow drift in the point in Mercury's elliptical orbit at which it approaches the Sun most closely). A total eclipse of the Sun that took place on 29 May 1919 provided an opportunity to put his theory of gravitational lensing to the test, and observations performed by Sir
Arthur Eddington Sir Arthur Stanley Eddington (28 December 1882 – 22 November 1944) was an English astronomer, physicist, and mathematician. He was also a philosopher of science and a populariser of science. The Eddington limit, the natural limit to the lumin ...
yielded results that were consistent with his calculations. Eddington's work was reported at length in newspapers around the world. On 7 November 1919, for example, the leading British newspaper, ''
The Times ''The Times'' is a British daily national newspaper based in London. It began in 1785 under the title ''The Daily Universal Register'', adopting its current name on 1 January 1788. ''The Times'' and its sister paper ''The Sunday Times'' (fou ...
'', printed a banner headline that read: "Revolution in Science – New Theory of the Universe – Newtonian Ideas Overthrown".


1921–1923: Coming to terms with fame

With Eddington's eclipse observations widely reported not just in academic journals but by the popular press as well, Einstein became "perhaps the world's first celebrity scientist", a genius who had shattered a paradigm that had been basic to physicists' understanding of the universe since the seventeenth century. Einstein began his new life as an intellectual icon in America, where he arrived on 2 April 1921. He was welcomed to New York City by Mayor John Francis Hylan, and then spent three weeks giving lectures and attending receptions. He spoke several times at
Columbia University Columbia University (also known as Columbia, and officially as Columbia University in the City of New York) is a private research university in New York City. Established in 1754 as King's College on the grounds of Trinity Church in Manhatt ...
and
Princeton Princeton University is a private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth as the College of New Jersey, Princeton is the fourth-oldest institution of higher education in the United States and one of the nine ...
, and in Washington, he visited the
White House The White House is the official residence and workplace of the president of the United States. It is located at 1600 Pennsylvania Avenue NW in Washington, D.C., and has been the residence of every U.S. president since John Adams in 1800. ...
with representatives of the
National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the Nati ...
. He returned to Europe via London, where he was the guest of the philosopher and statesman
Viscount Haldane A viscount ( , for male) or viscountess (, for female) is a title used in certain European countries for a noble of varying status. In many countries a viscount, and its historical equivalents, was a non-hereditary, administrative or judicial ...
. He used his time in the British capital to meet several people prominent in British scientific, political or intellectual life, and to deliver a lecture at King's College. In July 1921, he published an essay, "My First Impression of the U.S.A.", in which he sought to sketch the American character, much as had
Alexis de Tocqueville Alexis Charles Henri Clérel, comte de Tocqueville (; 29 July 180516 April 1859), colloquially known as Tocqueville (), was a French aristocrat, diplomat, political scientist, political philosopher and historian. He is best known for his works ...
in ''
Democracy in America (; published in two volumes, the first in 1835 and the second in 1840) is a classic French text by Alexis de Tocqueville. Its title literally translates to ''On Democracy in America'', but official English translations are usually simply entitl ...
'' (1835). He wrote of his transatlantic hosts in highly approving terms: "What strikes a visitor is the joyous, positive attitude to life ... The American is friendly, self-confident, optimistic, and without envy." In 1922, Einstein's travels were to the old world rather than the new. He devoted six months to a tour of Asia that saw him speaking in Japan, Singapore and Sri Lanka (then known as
Ceylon Sri Lanka (, ; si, ශ්‍රී ලංකා, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon and officially the Democratic Socialist Republic of Sri Lanka, is an ...
). After his first public lecture in Tokyo, he met
Emperor Yoshihito An emperor (from la, imperator, via fro, empereor) is a monarch, and usually the sovereign ruler of an empire or another type of imperial realm. Empress, the female equivalent, may indicate an emperor's wife ( empress consort), mother ( e ...
and his wife at the Imperial Palace, with thousands of spectators thronging the streets in the hope of catching a glimpse of him. (In a letter to his sons, he wrote that Japanese people seemed to him to be generally modest, intelligent and considerate, and to have a true appreciation of art. But his picture of them in his diary was less flattering: " heintellectual needs of this nation seem to be weaker than their artistic ones – natural disposition?" His journal also contains views of China and India which were uncomplimentary. Of Chinese people, he wrote that "even the children are spiritless and look obtuse... It would be a pity if these Chinese supplant all other races. For the likes of us the mere thought is unspeakably dreary".) He was greeted with even greater enthusiasm on the last leg of his tour, in which he spent twelve days in
Mandatory Palestine Mandatory Palestine ( ar, فلسطين الانتدابية '; he, פָּלֶשְׂתִּינָה (א״י) ', where "E.Y." indicates ''’Eretz Yiśrā’ēl'', the Land of Israel) was a geopolitical entity established between 1920 and 1948 ...
, newly entrusted to British rule by the
League of Nations The League of Nations (french: link=no, Société des Nations ) was the first worldwide intergovernmental organisation whose principal mission was to maintain world peace. It was founded on 10 January 1920 by the Paris Peace Conference that ...
in the aftermath of the First World War.
Sir Herbert Samuel Herbert Louis Samuel, 1st Viscount Samuel, (6 November 1870 – 5 February 1963) was a British Liberal politician who was the party leader from 1931 to 1935. He was the first nominally-practising Jew to serve as a Cabinet minister and to beco ...
, the British High Commissioner, welcomed him with a degree of ceremony normally only accorded to a visiting head of state, including a cannon salute. One reception held in his honor was stormed by people determined to hear him speak: he told them that he was happy that Jews were beginning to be recognized as a force in the world. Einstein's decision to tour the eastern hemisphere in 1922 meant that he was unable to go to
Stockholm Stockholm () is the Capital city, capital and List of urban areas in Sweden by population, largest city of Sweden as well as the List of urban areas in the Nordic countries, largest urban area in Scandinavia. Approximately 980,000 people liv ...
in the December of that year to participate in the Nobel prize ceremony. His place at the traditional Nobel banquet was taken by a German diplomat, who gave a speech praising him not only as a physicist but also as a campaigner for peace. A two-week visit to Spain that he undertook in 1923 saw him collecting another award, a membership of the Spanish Academy of Sciences signified by a diploma handed to him by
King Alfonso XIII Alfonso XIII (17 May 1886 – 28 February 1941), also known as El Africano or the African, was King of Spain from 17 May 1886 to 14 April 1931, when the Second Spanish Republic was proclaimed. He was a monarch from birth as his father, Alf ...
. (His Spanish trip also gave him a chance to meet a fellow Nobel laureate, the neuroanatomist
Santiago Ramón y Cajal Santiago Ramón y Cajal (; 1 May 1852 – 17 October 1934) was a Spanish neuroscientist, pathologist, and histologist specializing in neuroanatomy and the central nervous system. He and Camillo Golgi received the Nobel Prize in Physiology or Med ...
.)


1922–1932: Serving the League of Nations

From 1922 until 1932, with the exception of a few months in 1923 and 1924, Einstein was a member of the Geneva-based
International Committee on Intellectual Cooperation The International Committee on Intellectual Cooperation, sometimes League of Nations Committee on Intellectual Cooperation, was an advisory organization for the League of Nations which aimed to promote international exchange between scientists, r ...
of the
League of Nations The League of Nations (french: link=no, Société des Nations ) was the first worldwide intergovernmental organisation whose principal mission was to maintain world peace. It was founded on 10 January 1920 by the Paris Peace Conference that ...
, a group set up by the League to encourage scientists, artists, scholars, teachers and other people engaged in the life of the mind to work more closely with their counterparts in other countries. He was appointed as a German delegate rather than as a representative of Switzerland because of the machinations of two Catholic activists,
Oskar Halecki Oskar Halecki (26 May 1891, Vienna, Cisleithania, Austria-Hungary – 17 September 1973, White Plains, New York, United States of America) was a Polish historian, social and Catholic activist. Life and career Halecki, whose first name is sometim ...
and
Giuseppe Motta Giuseppe Motta (29 December 1871 – 23 January 1940) was a Swiss politician. He was a member of the Swiss Federal Council (1911–1940) and President of the League of Nations (1924–1925). He was a Catholic-conservative foreign minister and a s ...
. By persuading Secretary General
Eric Drummond James Eric Drummond, 7th Earl of Perth, (17 August 1876 – 15 December 1951), was a British politician and diplomat who was the first Secretary-General of the League of Nations (1920–1933). Quiet and unassuming, he succeeded in building an e ...
to deny Einstein the place on the committee reserved for a Swiss thinker, they created an opening for
Gonzague de Reynold Gonzague de Reynold (15 June 1880 – 9 April 1970) was a Swiss writer, historian, and right-wing political activist. Over the course of his six-decade career, he wrote more than thirty books outlining his traditionalist Catholic and Swiss natio ...
, who used his League of Nations position as a platform from which to promote traditional Catholic doctrine. Einstein's former physics professor
Hendrik Lorentz Hendrik Antoon Lorentz (; 18 July 1853 – 4 February 1928) was a Dutch physicist who shared the 1902 Nobel Prize in Physics with Pieter Zeeman for the discovery and theoretical explanation of the Zeeman effect. He also derived the Lorentz t ...
and the Polish chemist
Marie Curie Marie Salomea Skłodowska–Curie ( , , ; born Maria Salomea Skłodowska, ; 7 November 1867 – 4 July 1934) was a Polish and naturalized-French physicist and chemist who conducted pioneering research on radioactivity. She was the first ...
were also members of the committee.


1925: Touring South America

In March and April 1925, Einstein and his wife visited South America, where they spent about a week in Brazil, a week in Uruguay and a month in Argentina. Their tour was suggested by Jorge Duclout (1856–1927) and Mauricio Nirenstein (1877–1935) with the support of several Argentine scholars, including Julio Rey Pastor,
Jakob Laub Jakob Johann Laub (born as Jakub Laub, 7 February 1884 in Rzeszów – 22 April 1962 in Fribourg) was a physicist from Austria-Hungary, who is best known for his work with Albert Einstein in the early period of special relativity. Life He was the ...
, and
Leopoldo Lugones Leopoldo Antonio Lugones Argüello (13 June 1874 – 18 February 1938) was an Argentine poet, essayist, novelist, playwright, historian, professor, translator, biographer, philologist, theologian, diplomat, politician and journalist. His poetic ...
. and was financed primarily by the Council of the
University of Buenos Aires The University of Buenos Aires ( es, Universidad de Buenos Aires, UBA) is a public university, public research university in Buenos Aires, Argentina. Established in 1821, it is the premier institution of higher learning in the country and one o ...
and the ''Asociación Hebraica Argentina'' (Argentine Hebraic Association) with a smaller contribution from the Argentine-Germanic Cultural Institution.


1930–1931: Touring the US

In December 1930, Einstein began another significant sojourn in the United States, drawn back to the US by the offer of a two month research fellowship at the California Institute of Technology. Caltech supported him in his wish that he should not be exposed to quite as much attention from the media as he had experienced when visiting the US in 1921, and he therefore declined all the invitations to receive prizes or make speeches that his admirers poured down upon him. But he remained willing to allow his fans at least some of the time with him that they requested. After arriving in New York City, Einstein was taken to various places and events, including
Chinatown A Chinatown () is an ethnic enclave of Chinese people located outside Greater China, most often in an urban setting. Areas known as "Chinatown" exist throughout the world, including Europe, North America, South America, Asia, Africa and Austra ...
, a lunch with the editors of ''The New York Times'', and a performance of ''Carmen'' at the
Metropolitan Opera The Metropolitan Opera (commonly known as the Met) is an American opera company based in New York City, resident at the Metropolitan Opera House at Lincoln Center, currently situated on the Upper West Side of Manhattan. The company is operat ...
, where he was cheered by the audience on his arrival. During the days following, he was given the keys to the city by Mayor Jimmy Walker and met Nicholas Murray Butler, the president of
Columbia University Columbia University (also known as Columbia, and officially as Columbia University in the City of New York) is a private research university in New York City. Established in 1754 as King's College on the grounds of Trinity Church in Manhatt ...
, who described Einstein as "the ruling monarch of the mind". Harry Emerson Fosdick, pastor at New York's
Riverside Church Riverside Church is an interdenominational church in the Morningside Heights neighborhood of Manhattan, New York City, on the block bounded by Riverside Drive, Claremont Avenue, 120th Street and 122nd Street near Columbia University's Mornings ...
, gave Einstein a tour of the church and showed him a full-size statue that the church made of Einstein, standing at the entrance. Also during his stay in New York, he joined a crowd of 15,000 people at
Madison Square Garden Madison Square Garden, colloquially known as The Garden or by its initials MSG, is a multi-purpose indoor arena in New York City. It is located in Midtown Manhattan between Seventh and Eighth avenues from 31st to 33rd Street, above Pennsylva ...
during a
Hanukkah or English translation: 'Establishing' or 'Dedication' (of the Temple in Jerusalem) , nickname = , observedby = Jews , begins = 25 Kislev , ends = 2 Tevet or 3 Tevet , celebrations = Lighting candles each night. ...
celebration. Einstein next traveled to California, where he met
Caltech The California Institute of Technology (branded as Caltech or CIT)The university itself only spells its short form as "Caltech"; the institution considers other spellings such a"Cal Tech" and "CalTech" incorrect. The institute is also occasional ...
president and Nobel laureate Robert A. Millikan. His friendship with Millikan was "awkward", as Millikan "had a penchant for patriotic militarism", where Einstein was a pronounced
pacifist Pacifism is the opposition or resistance to war, militarism (including conscription and mandatory military service) or violence. Pacifists generally reject theories of Just War. The word ''pacifism'' was coined by the French peace campaign ...
. During an address to Caltech's students, Einstein noted that science was often inclined to do more harm than good. This aversion to war also led Einstein to befriend author
Upton Sinclair Upton Beall Sinclair Jr. (September 20, 1878 – November 25, 1968) was an American writer, muckraker, political activist and the 1934 Democratic Party nominee for governor of California who wrote nearly 100 books and other works in seve ...
and film star
Charlie Chaplin Sir Charles Spencer Chaplin Jr. (16 April 188925 December 1977) was an English comic actor, filmmaker, and composer who rose to fame in the era of silent film. He became a worldwide icon through his screen persona, the Tramp, and is consider ...
, both noted for their pacifism. Carl Laemmle, head of
Universal Studios Universal Pictures (legally Universal City Studios LLC, also known as Universal Studios, or simply Universal; common metonym: Uni, and formerly named Universal Film Manufacturing Company and Universal-International Pictures Inc.) is an Ameri ...
, gave Einstein a tour of his studio and introduced him to Chaplin. They had an instant rapport, with Chaplin inviting Einstein and his wife, Elsa, to his home for dinner. Chaplin said Einstein's outward persona, calm and gentle, seemed to conceal a "highly emotional temperament", from which came his "extraordinary intellectual energy". Chaplin's film ''
City Lights ''City Lights'' is a 1931 American silent romantic comedy film written, produced, directed by, and starring Charlie Chaplin. The story follows the misadventures of Chaplin's Tramp as he falls in love with a blind girl (Virginia Cherrill) and ...
'' was to premiere a few days later in Hollywood, and Chaplin invited Einstein and Elsa to join him as his special guests.
Walter Isaacson Walter Seff Isaacson (born May 20, 1952) is an American author, journalist, and professor. He has been the President and CEO of the Aspen Institute, a nonpartisan policy studies organization based in Washington, D.C., the chair and CEO of CNN, ...
, Einstein's biographer, described this as "one of the most memorable scenes in the new era of celebrity". Chaplin visited Einstein at his home on a later trip to Berlin and recalled his "modest little flat" and the piano at which he had begun writing his theory. Chaplin speculated that it was "possibly used as kindling wood by the Nazis".


1933: Emigration to the US

In February 1933, while on a visit to the United States, Einstein knew he could not return to Germany with the rise to power of the
Nazis Nazism ( ; german: Nazismus), the common name in English for National Socialism (german: Nationalsozialismus, ), is the far-right totalitarian political ideology and practices associated with Adolf Hitler and the Nazi Party (NSDAP) in Na ...
under Germany's new chancellor,
Adolf Hitler Adolf Hitler (; 20 April 188930 April 1945) was an Austrian-born German politician who was dictator of Nazi Germany, Germany from 1933 until Death of Adolf Hitler, his death in 1945. Adolf Hitler's rise to power, He rose to power as the le ...
. While at American universities in early 1933, he undertook his third two-month visiting professorship at the California Institute of Technology in Pasadena. In February and March 1933, the
Gestapo The (), abbreviated Gestapo (; ), was the official secret police of Nazi Germany and in German-occupied Europe. The force was created by Hermann Göring in 1933 by combining the various political police agencies of Prussia into one organi ...
repeatedly raided his family's apartment in Berlin. He and his wife Elsa returned to Europe in March, and during the trip, they learned that the German Reichstag had passed the
Enabling Act An enabling act is a piece of legislation by which a legislative body grants an entity which depends on it (for authorization or legitimacy) the power to take certain actions. For example, enabling acts often establish government agencies to car ...
on 23 March, transforming Hitler's government into a ''de facto'' legal dictatorship, and that they would not be able to proceed to Berlin. Later on, they heard that their cottage had been raided by the Nazis and Einstein's personal sailboat confiscated. Upon landing in
Antwerp Antwerp (; nl, Antwerpen ; french: Anvers ; es, Amberes) is the largest city in Belgium by area at and the capital of Antwerp Province in the Flemish Region. With a population of 520,504,
, Belgium on 28 March, Einstein immediately went to the German consulate and surrendered his passport, formally renouncing his German citizenship. The Nazis later sold his boat and converted his cottage into a
Hitler Youth The Hitler Youth (german: Hitlerjugend , often abbreviated as HJ, ) was the youth organisation of the Nazi Party in Germany. Its origins date back to 1922 and it received the name ("Hitler Youth, League of German Worker Youth") in July 1926. ...
camp.


Refugee status

In April 1933, Einstein discovered that the new German government had passed laws barring Jews from holding any official positions, including teaching at universities. Historian
Gerald Holton Gerald James Holton (born May 23, 1922) is an American physicist, historian of science, and educator, whose professional interests also include philosophy of science and the fostering of careers of young men and women. He is Mallinckrodt Profes ...
describes how, with "virtually no audible protest being raised by their colleagues", thousands of Jewish scientists were suddenly forced to give up their university positions and their names were removed from the rolls of institutions where they were employed. A month later, Einstein's works were among those targeted by the German Student Union in the Nazi book burnings, with Nazi propaganda minister
Joseph Goebbels Paul Joseph Goebbels (; 29 October 1897 – 1 May 1945) was a German Nazi politician who was the ''Gauleiter'' (district leader) of Berlin, chief propagandist for the Nazi Party, and then Reich Minister of Propaganda from 1933 to 19 ...
proclaiming, "Jewish intellectualism is dead." One German magazine included him in a list of enemies of the German regime with the phrase, "not yet hanged", offering a $5,000 bounty on his head. In a subsequent letter to physicist and friend
Max Born Max Born (; 11 December 1882 – 5 January 1970) was a German physicist and mathematician who was instrumental in the development of quantum mechanics. He also made contributions to solid-state physics and optics and supervised the work of a n ...
, who had already emigrated from Germany to England, Einstein wrote, "... I must confess that the degree of their brutality and cowardice came as something of a surprise." After moving to the US, he described the book burnings as a "spontaneous emotional outburst" by those who "shun popular enlightenment", and "more than anything else in the world, fear the influence of men of intellectual independence". Einstein was now without a permanent home, unsure where he would live and work, and equally worried about the fate of countless other scientists still in Germany. Aided by the
Academic Assistance Council The Council for At-Risk Academics (CARA) is a charitable British organisation dedicated to assisting academics in immediate danger, those forced into exile, and many who choose to remain in their home countries despite the serious risks they face ...
, founded in April 1933 by British Liberal politician
William Beveridge William Henry Beveridge, 1st Baron Beveridge, (5 March 1879 – 16 March 1963) was a British economist and Liberal politician who was a progressive and social reformer who played a central role in designing the British welfare state. His 194 ...
to help academics escape Nazi persecution, Einstein was able to leave Germany. He rented a house in De Haan, Belgium, where he lived for a few months. In late July 1933, he visited England for about six weeks at the invitation of the British Member of Parliament Commander Oliver Locker-Lampson, who had become friends with him in the preceding years. Locker-Lampson invited him to stay near his home in a secluded wooden cabin on Roughton Heath in the Parish of . To protect Einstein, Locker-Lampson had two bodyguards watch over him; a photo of them carrying shotguns and guarding Einstein was published in the ''Daily Herald'' on 24 July 1933. Locker-Lampson took Einstein to meet
Winston Churchill Sir Winston Leonard Spencer Churchill (30 November 187424 January 1965) was a British statesman, soldier, and writer who served as Prime Minister of the United Kingdom twice, from 1940 to 1945 Winston Churchill in the Second World War, dur ...
at his home, and later, Austen Chamberlain and former Prime Minister
Lloyd George David Lloyd George, 1st Earl Lloyd-George of Dwyfor, (17 January 1863 – 26 March 1945) was Prime Minister of the United Kingdom from 1916 to 1922. He was a Liberal Party (United Kingdom), Liberal Party politician from Wales, known for lea ...
. Einstein asked them to help bring Jewish scientists out of Germany. British historian
Martin Gilbert Sir Martin John Gilbert (25 October 1936 – 3 February 2015) was a British historian and honorary Fellow of Merton College, Oxford. He was the author of eighty-eight books, including works on Winston Churchill, the 20th century, and Jewish h ...
notes that Churchill responded immediately, and sent his friend, physicist
Frederick Lindemann Frederick Alexander Lindemann, 1st Viscount Cherwell, ( ; 5 April 18863 July 1957) was a British physicist who was prime scientific adviser to Winston Churchill in World War II. Lindemann was a brilliant intellectual, who cut through bureauc ...
, to Germany to seek out Jewish scientists and place them in British universities. Churchill later observed that as a result of Germany having driven the Jews out, they had lowered their "technical standards" and put the Allies' technology ahead of theirs. Einstein later contacted leaders of other nations, including
Turkey Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a list of transcontinental countries, transcontinental country located mainly on the Anatolia, Anatolian Peninsula in Western Asia, with ...
's Prime Minister,
İsmet İnönü Mustafa İsmet İnönü (; 24 September 1884 – 25 December 1973) was a Turkish army officer and statesman of Kurdish descent, who served as the second President of Turkey from 11 November 1938 to 22 May 1950, and its Prime Minister three tim ...
, to whom he wrote in September 1933 requesting placement of unemployed German-Jewish scientists. As a result of Einstein's letter, Jewish invitees to Turkey eventually totaled over "1,000 saved individuals". Locker-Lampson also submitted a bill to parliament to extend British citizenship to Einstein, during which period Einstein made a number of public appearances describing the crisis brewing in Europe. In one of his speeches he denounced Germany's treatment of Jews, while at the same time he introduced a bill promoting Jewish citizenship in Palestine, as they were being denied citizenship elsewhere. In his speech he described Einstein as a "citizen of the world" who should be offered a temporary shelter in the UK. Both bills failed, however, and Einstein then accepted an earlier offer from the
Institute for Advanced Study The Institute for Advanced Study (IAS), located in Princeton, New Jersey, in the United States, is an independent center for theoretical research and intellectual inquiry. It has served as the academic home of internationally preeminent scholar ...
, in
Princeton, New Jersey Princeton is a municipality with a borough form of government in Mercer County, in the U.S. state of New Jersey. It was established on January 1, 2013, through the consolidation of the Borough of Princeton and Princeton Township, both of whi ...
, US, to become a resident scholar.


Resident scholar at the Institute for Advanced Study

On 3 October 1933, Einstein delivered a speech on the importance of academic freedom before a packed audience at the
Royal Albert Hall The Royal Albert Hall is a concert hall on the northern edge of South Kensington, London. One of the UK's most treasured and distinctive buildings, it is held in trust for the nation and managed by a registered charity which receives no govern ...
in London, with ''
The Times ''The Times'' is a British daily national newspaper based in London. It began in 1785 under the title ''The Daily Universal Register'', adopting its current name on 1 January 1788. ''The Times'' and its sister paper ''The Sunday Times'' (fou ...
'' reporting he was wildly cheered throughout. Four days later he returned to the US and took up a position at the
Institute for Advanced Study The Institute for Advanced Study (IAS), located in Princeton, New Jersey, in the United States, is an independent center for theoretical research and intellectual inquiry. It has served as the academic home of internationally preeminent scholar ...
, noted for having become a refuge for scientists fleeing Nazi Germany. At the time, most American universities, including Harvard, Princeton and Yale, had minimal or no Jewish faculty or students, as a result of their Jewish quotas, which lasted until the late 1940s. Einstein was still undecided on his future. He had offers from several European universities, including
Christ Church, Oxford Christ Church ( la, Ædes Christi, the temple or house, '' ædēs'', of Christ, and thus sometimes known as "The House") is a constituent college of the University of Oxford in England. Founded in 1546 by King Henry VIII, the college is uniqu ...
, where he stayed for three short periods between May 1931 and June 1933 and was offered a five-year research
fellowship A fellow is a concept whose exact meaning depends on context. In learned or professional societies, it refers to a privileged member who is specially elected in recognition of their work and achievements. Within the context of higher education ...
(called a "
studentship A studentship is a type of academic scholarship. United States In the US a ''studentship'' is similar to a scholarship but involves summer work on a research project. The amount paid to the recipient is normally tax-free, but the recipient is ...
" at Christ Church), but in 1935, he arrived at the decision to remain permanently in the United States and apply for citizenship. Einstein's affiliation with the Institute for Advanced Study would last until his death in 1955. He was one of the four first selected (along with
John von Neumann John von Neumann (; hu, Neumann János Lajos, ; December 28, 1903 – February 8, 1957) was a Hungarian-American mathematician, physicist, computer scientist, engineer and polymath. He was regarded as having perhaps the widest cove ...
,
Kurt Gödel Kurt Friedrich Gödel ( , ; April 28, 1906 – January 14, 1978) was a logician, mathematician, and philosopher. Considered along with Aristotle and Gottlob Frege to be one of the most significant logicians in history, Gödel had an imme ...
, and
Hermann Weyl Hermann Klaus Hugo Weyl, (; 9 November 1885 – 8 December 1955) was a German mathematician, theoretical physicist and philosopher. Although much of his working life was spent in Zürich, Switzerland, and then Princeton, New Jersey, he is assoc ...
) at the new Institute. He soon developed a close friendship with Gödel; the two would take long walks together discussing their work.
Bruria Kaufman Bruria Kaufman (August 21, 1918 – January 7, 2010) was an American theoretical physicist. She is known for contributions to Albert Einstein's general theory of relativity, to statistical physics, where she used applied spinor analysis to red ...
, his assistant, later became a physicist. During this period, Einstein tried to develop a
unified field theory In physics, a unified field theory (UFT) is a type of field theory that allows all that is usually thought of as fundamental forces and elementary particles to be written in terms of a pair of physical and virtual fields. According to the modern ...
and to refute the accepted interpretation of
quantum physics Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, qua ...
, both unsuccessfully. He lived in Princeton at his home from 1935 onwards. The Albert Einstein House was made a
National Historic Landmark A National Historic Landmark (NHL) is a building, district, object, site, or structure that is officially recognized by the United States government for its outstanding historical significance. Only some 2,500 (~3%) of over 90,000 places listed ...
in 1976.


World War II and the Manhattan Project

In 1939, a group of Hungarian scientists that included émigré physicist Leó Szilárd attempted to alert
Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered on ...
to ongoing Nazi atomic bomb research. The group's warnings were discounted. Einstein and Szilárd, along with other refugees such as Edward Teller and Eugene Wigner, "regarded it as their responsibility to alert Americans to the possibility that German scientists might win the race to build an atomic bomb, and to warn that Hitler would be more than willing to resort to such a weapon." To make certain the US was aware of the danger, in July 1939, a few months before the beginning of World War II in Europe, Szilárd and Wigner visited Einstein to explain the possibility of atomic bombs, which Einstein, a pacifist, said he had never considered. He was asked to lend his support by writing a letter, with Szilárd, to President Roosevelt, recommending the US pay attention and engage in its own nuclear weapons research. The letter is believed to be "arguably the key stimulus for the U.S. adoption of serious investigations into nuclear weapons on the eve of the U.S. entry into World War II". In addition to the letter, Einstein used his connections with the Belgian royal family and the Belgian queen mother to get access with a personal envoy to the White House's Oval Office. Some say that as a result of Einstein's letter and his meetings with Roosevelt, the US entered the "race" to develop the bomb, drawing on its "immense material, financial, and scientific resources" to initiate the
Manhattan Project The Manhattan Project was a research and development undertaking during World War II that produced the first nuclear weapons. It was led by the United States with the support of the United Kingdom and Canada. From 1942 to 1946, the project w ...
. For Einstein, "war was a disease ... ndhe called for resistance to war." By signing the letter to Roosevelt, some argue he went against his pacifist principles. In 1954, a year before his death, Einstein said to his old friend,
Linus Pauling Linus Carl Pauling (; February 28, 1901August 19, 1994) was an American chemist, biochemist, chemical engineer, peace activist, author, and educator. He published more than 1,200 papers and books, of which about 850 dealt with scientific top ...
, "I made one great mistake in my life—when I signed the letter to President Roosevelt recommending that atom bombs be made; but there was some justification—the danger that the Germans would make them ..." In 1955, Einstein and ten other intellectuals and scientists, including British philosopher
Bertrand Russell Bertrand Arthur William Russell, 3rd Earl Russell, (18 May 1872 – 2 February 1970) was a British mathematician, philosopher, logician, and public intellectual. He had a considerable influence on mathematics, logic, set theory, linguistics, ...
, signed a manifesto highlighting the danger of nuclear weapons. In 1960 Einstein was included posthumously as a charter member of the
World Academy of Art and Science The World Academy of Art and Science (WAAS), founded in 1960, is an international non-governmental scientific organization and global network of more than 800 scientists, artists, and scholars in more than 90 countries. It serves as a forum for s ...
(WAAS), an organization founded by distinguished scientists and intellectuals who committed themselves to the responsible and ethical advances of science, particularly in light of the development of nuclear weapons.


US citizenship

Einstein became an American citizen in 1940. Not long after settling into his career at the Institute for Advanced Study in Princeton, New Jersey, he expressed his appreciation of the
meritocracy Meritocracy (''merit'', from Latin , and ''-cracy'', from Ancient Greek 'strength, power') is the notion of a political system in which economic goods and/or political power are vested in individual people based on talent, effort, and achiev ...
in American culture compared to Europe. He recognized the "right of individuals to say and think what they pleased" without social barriers. As a result, individuals were encouraged, he said, to be more creative, a trait he valued from his early education. Einstein joined the
National Association for the Advancement of Colored People The National Association for the Advancement of Colored People (NAACP) is a civil rights organization in the United States, formed in 1909 as an interracial endeavor to advance justice for African Americans by a group including W. E. ...
(NAACP) in Princeton, where he campaigned for the
civil rights Civil and political rights are a class of rights that protect individuals' freedom from infringement by governments, social organizations, and private individuals. They ensure one's entitlement to participate in the civil and political life of ...
of African Americans. He considered racism America's "worst disease", seeing it as "handed down from one generation to the next". As part of his involvement, he corresponded with civil rights activist
W. E. B. Du Bois William Edward Burghardt Du Bois ( ; February 23, 1868 – August 27, 1963) was an American-Ghanaian sociologist, socialist, historian, and Pan-Africanist civil rights activist. Born in Great Barrington, Massachusetts, Du Bois grew up in ...
and was prepared to testify on his behalf during his trial as an alleged foreign agent in 1951. When Einstein offered to be a character witness for Du Bois, the judge decided to drop the case. In 1946, Einstein visited Lincoln University in Pennsylvania, a
historically black college Historically black colleges and universities (HBCUs) are institutions of higher education in the United States that were established before the Civil Rights Act of 1964 with the intention of primarily serving the African-American community. Mo ...
, where he was awarded an honorary degree. Lincoln was the first university in the United States to grant college degrees to African Americans; alumni include
Langston Hughes James Mercer Langston Hughes (February 1, 1901 – May 22, 1967) was an American poet, social activist, novelist, playwright, and columnist from Joplin, Missouri. One of the earliest innovators of the literary art form called jazz poetry, Hug ...
and
Thurgood Marshall Thurgood Marshall (July 2, 1908 – January 24, 1993) was an American civil rights lawyer and jurist who served as an associate justice of the Supreme Court of the United States from 1967 until 1991. He was the Supreme Court's first African-A ...
. Einstein gave a speech about racism in America, adding, "I do not intend to be quiet about it." A resident of Princeton recalls that Einstein had once paid the college tuition for a black student. Einstein has said, "Being a Jew myself, perhaps I can understand and empathize with how black people feel as victims of discrimination".


Personal views


Political views

In 1918, Einstein was one of the signatories of the founding proclamation of the German Democratic Party, a liberal party. Later in his life, Einstein's political view was in favor of
socialism Socialism is a left-wing economic philosophy and movement encompassing a range of economic systems characterized by the dominance of social ownership of the means of production as opposed to private ownership. As a term, it describes the e ...
and critical of capitalism, which he detailed in his essays such as "
Why Socialism? "Why Socialism?" is an article written by Albert Einstein in May 1949 that appeared in the first issue of the socialist journal '' Monthly Review''. It addresses problems with capitalism, predatory economic competition, and growing wealth inequali ...
". His opinions on the
Bolsheviks The Bolsheviks (russian: Большевики́, from большинство́ ''bol'shinstvó'', 'majority'),; derived from ''bol'shinstvó'' (большинство́), "majority", literally meaning "one of the majority". also known in English ...
also changed with time. In 1925, he criticized them for not having a "well-regulated system of government" and called their rule a "regime of terror and a tragedy in human history". He later adopted a more moderated view, criticizing their methods but praising them, which is shown by his 1929 remark on
Vladimir Lenin Vladimir Ilyich Ulyanov. ( 1870 – 21 January 1924), better known as Vladimir Lenin,. was a Russian revolutionary, politician, and political theorist. He served as the first and founding head of government of Soviet Russia from 1917 to 19 ...
: Einstein offered and was called on to give judgments and opinions on matters often unrelated to theoretical physics or mathematics. He strongly advocated the idea of a democratic
global government World government is the concept of a single political authority with jurisdiction over all humanity. It is conceived in a variety of forms, from tyrannical to democratic, which reflects its wide array of proponents and detractors. A world gove ...
that would check the power of nation-states in the framework of a world federation. He wrote "I advocate world government because I am convinced that there is no other possible way of eliminating the most terrible danger in which man has ever found himself." The FBI created a secret dossier on Einstein in 1932; by the time of his death, it was 1,427 pages long. Einstein was deeply impressed by
Mahatma Gandhi Mohandas Karamchand Gandhi (; ; 2 October 1869 – 30 January 1948), popularly known as Mahatma Gandhi, was an Indian lawyer, anti-colonial nationalist Quote: "... marks Gandhi as a hybrid cosmopolitan figure who transformed ... anti- ...
, with whom he corresponded. He described Gandhi as "a role model for the generations to come". The initial connection was established on 27 September 1931, when
Wilfrid Israel Wilfrid Berthold Jacob Israel (11 July 1899 – 1 June 1943) was an Anglo-German businessman and philanthropist, born into a wealthy Anglo-German Jewish family, who was active in the rescue of Jews from Nazi Germany, and who played a significan ...
took his Indian guest
V. A. Sundaram Vellalore Annaswamy Sundaram (2 February 1896 – 11 March 1967) was an activist in the Indian Independence movement, an associate of Mahatma Gandhi, a confidant of Madan Mohan Malaviya, and a fundraiser and secretary to the Benares Hindu U ...
to meet his friend Einstein at his summer home in the town of Caputh. Sundaram was Gandhi's disciple and special envoy, whom Wilfrid Israel met while visiting India and visiting the Indian leader's home in 1925. During the visit, Einstein wrote a short letter to Gandhi that was delivered to him through his envoy, and Gandhi responded quickly with his own letter. Although in the end Einstein and Gandhi were unable to meet as they had hoped, the direct connection between them was established through Wilfrid Israel.


Relationship with Zionism

Einstein was a figurehead leader in the establishment of the
Hebrew University of Jerusalem The Hebrew University of Jerusalem (HUJI; he, הַאוּנִיבֶרְסִיטָה הַעִבְרִית בִּירוּשָׁלַיִם) is a public research university based in Jerusalem, Israel. Co-founded by Albert Einstein and Dr. Chaim Weiz ...
, which opened in 1925. Earlier, in 1921, he was asked by the biochemist and president of the
World Zionist Organization The World Zionist Organization ( he, הַהִסְתַּדְּרוּת הַצִּיּוֹנִית הָעוֹלָמִית; ''HaHistadrut HaTzionit Ha'Olamit''), or WZO, is a non-governmental organization that promotes Zionism. It was founded as the ...
,
Chaim Weizmann Chaim Azriel Weizmann ( he, חיים עזריאל ויצמן ', russian: Хаим Евзорович Вейцман, ''Khaim Evzorovich Veytsman''; 27 November 1874 – 9 November 1952) was a Russian-born biochemist, Zionist leader and Israel ...
, to help raise funds for the planned university. He made suggestions for the creation of an Institute of Agriculture, a Chemical Institute and an Institute of Microbiology in order to fight the various ongoing epidemics such as
malaria Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. S ...
, which he called an "evil" that was undermining a third of the country's development. He also promoted the establishment of an Oriental Studies Institute, to include language courses given in both Hebrew and Arabic. Einstein was not a
nationalist Nationalism is an idea and movement that holds that the nation should be congruent with the state. As a movement, nationalism tends to promote the interests of a particular nation (as in a group of people), Smith, Anthony. ''Nationalism: The ...
and opposed the creation of an independent Jewish state. He felt that the waves of arriving Jews of the
Aliyah Aliyah (, ; he, עֲלִיָּה ''ʿălīyyā'', ) is the immigration of Jews from Jewish diaspora, the diaspora to, historically, the geographical Land of Israel, which is in the modern era chiefly represented by the Israel, State of Israel ...
could live alongside existing Arabs in
Palestine __NOTOC__ Palestine may refer to: * State of Palestine, a state in Western Asia * Palestine (region), a geographic region in Western Asia * Palestinian territories, territories occupied by Israel since 1967, namely the West Bank (including East ...
. The state of
Israel Israel (; he, יִשְׂרָאֵל, ; ar, إِسْرَائِيل, ), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a country in Western Asia. It is situated ...
was established without his help in 1948; Einstein was limited to a marginal role in the
Zionist movement Zionism ( he, צִיּוֹנוּת ''Tsiyyonut'' after ''Zion'') is a nationalist movement that espouses the establishment of, and support for a homeland for the Jewish people centered in the area roughly corresponding to what is known in Jew ...
. Upon the death of Israeli president Weizmann in November 1952, Prime Minister
David Ben-Gurion David Ben-Gurion ( ; he, דָּוִד בֶּן-גּוּרִיּוֹן ; born David Grün; 16 October 1886 – 1 December 1973) was the primary national founder of the State of Israel and the first prime minister of Israel. Adopting the name ...
offered Einstein the largely ceremonial position of
President of Israel The president of the State of Israel ( he, נְשִׂיא מְדִינַת יִשְׂרָאֵל, Nesi Medinat Yisra'el, or he, נְשִׂיא הַמְדִינָה, Nesi HaMedina, President of the State) is the head of state of Israel. The posi ...
at the urging of
Ezriel Carlebach Ezriel Carlebach (also ''Azriel''; born Esriel Gotthelf Carlebach, he, עזריאל קרליבך, yi, עזריאל קארלעבאך; November 7, 1908 – February 12, 1956) was a leading journalist and editorial writer during the period of Jewi ...
. The offer was presented by Israel's ambassador in Washington, Abba Eban, who explained that the offer "embodies the deepest respect which the Jewish people can repose in any of its sons". Einstein wrote that he was "deeply moved", but "at once saddened and ashamed" that he could not accept it.


Religious and philosophical views

Einstein expounded his spiritual outlook in a wide array of writings and interviews. He said he had sympathy for the impersonal pantheistic God of Baruch Spinoza's philosophy. He did not believe in a personal god who concerns himself with fates and actions of human beings, a view which he described as naïve. He clarified, however, that "I am not an atheist", preferring to call himself an agnostic, or a "deeply religious nonbeliever". When asked if he believed in an
afterlife The afterlife (also referred to as life after death) is a purported existence in which the essential part of an individual's identity or their stream of consciousness continues to live after the death of their physical body. The surviving ess ...
, Einstein replied, "No. And one life is enough for me." Einstein was primarily affiliated with non-religious humanist and
Ethical Culture The Ethical movement, also referred to as the Ethical Culture movement, Ethical Humanism or simply Ethical Culture, is an ethical, educational, and religious movement that is usually traced back to Felix Adler (1851–1933).
groups in both the UK and US. He served on the advisory board of the
First Humanist Society of New York In 1929 Charles Francis Potter founded the First Humanist Society of New York whose advisory board included Julian Huxley, John Dewey, Albert Einstein, and Thomas Mann. Potter was a minister from the Unitarian tradition and in 1930 he and his wife ...
, and was an honorary associate of the
Rationalist Association The Rationalist Association, originally the Rationalist Press Association, is an organization in the United Kingdom, founded in 1885 by a group of freethinkers who were unhappy with the increasingly political and decreasingly intellectual tenor ...
, which publishes ''
New Humanist ''New Humanist'' is a quarterly magazine, published by the Rationalist Association in the UK, that focuses on culture, news, philosophy, and science from a sceptical perspective. History The ''New Humanist'' has been in print for more than 131 ...
'' in Britain. For the 75th anniversary of the
New York Society for Ethical Culture The Ethical movement, also referred to as the Ethical Culture movement, Ethical Humanism or simply Ethical Culture, is an ethical, educational, and religion, religious movement that is usually traced back to Felix Adler (professor), Felix Adler ...
, he stated that the idea of Ethical Culture embodied his personal conception of what is most valuable and enduring in religious idealism. He observed, "Without 'ethical culture' there is no salvation for humanity." In a German-language letter to philosopher
Eric Gutkind Eric Gutkind (also: ''Erich'') (9 February 1877 – 26 August 1965) was a German Jewish philosopher, born in Berlin. Life His parents were Hermann Gutkind and Elise Weinberg (1852–1942). Eric Gutkind was born in Berlin and educated at ...
, dated 3 January 1954, Einstein wrote:
The word God is for me nothing more than the expression and product of human weaknesses, the Bible a collection of honorable, but still primitive legends which are nevertheless pretty childish. No interpretation no matter how subtle can (for me) change this. ... For me the Jewish religion like all other religions is an incarnation of the most childish superstitions. And the
Jewish people Jews ( he, יְהוּדִים, , ) or Jewish people are an ethnoreligious group and nation originating from the Israelites Israelite origins and kingdom: "The first act in the long drama of Jewish history is the age of the Israelites""Th ...
to whom I gladly belong and with whose mentality I have a deep affinity have no different quality for me than all other people. ... I cannot see anything ' chosen' about them.
Einstein had been sympathetic toward vegetarianism for a long time. In a letter in 1930 to Hermann Huth, vice-president of the German Vegetarian Federation (Deutsche Vegetarier-Bund), he wrote:
Although I have been prevented by outward circumstances from observing a strictly vegetarian diet, I have long been an adherent to the cause in principle. Besides agreeing with the aims of vegetarianism for aesthetic and moral reasons, it is my view that a vegetarian manner of living by its purely physical effect on the human temperament would most beneficially influence the lot of mankind.
He became a vegetarian himself only during the last part of his life. In March 1954 he wrote in a letter: "So I am living without fats, without meat, without fish, but am feeling quite well this way. It almost seems to me that man was not born to be a carnivore."


Love of music

Einstein developed an appreciation for music at an early age. In his late journals he wrote: His mother played the piano reasonably well and wanted her son to learn the violin, not only to instill in him a love of music but also to help him assimilate into
German culture The culture of Germany has been shaped by major intellectual and popular currents in Europe, both religious and secular. Historically, Germany has been called ''Das Land der Dichter und Denker'' (the country of poets and thinkers). German cultu ...
. According to conductor Leon Botstein, Einstein began playing when he was 5. However, he did not enjoy it at that age. When he turned 13, he discovered the violin sonatas of Mozart, whereupon he became enamored of
Mozart Wolfgang Amadeus Mozart (27 January 17565 December 1791), baptised as Joannes Chrysostomus Wolfgangus Theophilus Mozart, was a prolific and influential composer of the Classical period (music), Classical period. Despite his short life, his ra ...
's compositions and studied music more willingly. Einstein taught himself to play without "ever practicing systematically". He said that "love is a better teacher than a sense of duty". At the age of 17, he was heard by a school examiner in Aarau while playing
Beethoven's violin sonatas Ludwig van Beethoven composed the following violin sonatas between 1798 and 1812. * Violin Sonata in A major (Beethoven) The Violin Sonata in A major, Hess 46, is a fragmentary and possibly unfinished work for piano and violin composed by Ludwig va ...
. The examiner stated afterward that his playing was "remarkable and revealing of 'great insight. What struck the examiner, writes Botstein, was that Einstein "displayed a deep love of the music, a quality that was and remains in short supply. Music possessed an unusual meaning for this student." Music took on a pivotal and permanent role in Einstein's life from that period on. Although the idea of becoming a professional musician himself was not on his mind at any time, among those with whom Einstein played
chamber music Chamber music is a form of classical music that is composed for a small group of instruments—traditionally a group that could fit in a palace chamber or a large room. Most broadly, it includes any art music that is performed by a small numb ...
were a few professionals, including Kurt Appelbaum, and he performed for private audiences and friends. Chamber music had also become a regular part of his social life while living in Bern, Zürich, and Berlin, where he played with Max Planck and his son, among others. He is sometimes erroneously credited as the editor of the 1937 edition of the Köchel catalog of Mozart's work; that edition was prepared by
Alfred Einstein Alfred Einstein (December 30, 1880February 13, 1952) was a German-American musicologist and music editor. He was born in Munich and fled Nazi Germany after Hitler's ''Machtergreifung'', arriving in the United States by 1939. He is best known for b ...
, who may have been a distant relation. In 1931, while engaged in research at the California Institute of Technology, he visited the Zoellner family conservatory in Los Angeles, where he played some of
Beethoven Ludwig van Beethoven (baptised 17 December 177026 March 1827) was a German composer and pianist. Beethoven remains one of the most admired composers in the history of Western music; his works rank amongst the most performed of the classical ...
and Mozart's works with members of the
Zoellner Quartet The Zoellner Quartet was a string quartet active during the first quarter of the 20th century. It was once described as "the most celebrated musical organization in the West which devotes its energies exclusively to the highest class of chamb ...
. Near the end of his life, when the young
Juilliard Quartet The Juilliard String Quartet is a classical music string quartet founded in 1946 at the Juilliard School in New York by William Schuman. Since its inception, it has been the quartet-in-residence at the Juilliard School. It has received numerous ...
visited him in Princeton, he played his violin with them, and the quartet was "impressed by Einstein's level of coordination and intonation".


Death

On 17 April 1955, Einstein experienced internal bleeding caused by the rupture of an abdominal aortic aneurysm, which had previously been reinforced surgically by Rudolph Nissen in 1948. He took the draft of a speech he was preparing for a television appearance commemorating the state of Israel's seventh anniversary with him to the hospital, but he did not live to complete it. Einstein refused surgery, saying, "I want to go when I want. It is tasteless to prolong life artificially. I have done my share; it is time to go. I will do it elegantly." He died in the
Princeton Hospital Penn Medicine Princeton Medical Center (PMC), formerly known as the University Medical Center of Princeton at Plainsboro, is a 355-bed non-profit, tertiary, and academic medical center located in Plainsboro Township, New Jersey, servicing the wes ...
early the next morning at the age of 76, having continued to work until near the end. During the autopsy, the pathologist
Thomas Stoltz Harvey Thomas Stoltz Harvey (October 10, 1912 – April 5, 2007) was an American pathologist who conducted the autopsy on Albert Einstein in 1955. Harvey later kept Einstein's brain without permission for decades. Early career Harvey studied at Yale U ...
removed Einstein's brain for preservation without the permission of his family, in the hope that the
neuroscience Neuroscience is the scientific study of the nervous system (the brain, spinal cord, and peripheral nervous system), its functions and disorders. It is a multidisciplinary science that combines physiology, anatomy, molecular biology, development ...
of the future would be able to discover what made Einstein so intelligent. Einstein's remains were cremated in
Trenton, New Jersey Trenton is the capital city of the U.S. state of New Jersey and the county seat of Mercer County. It was the capital of the United States from November 1 to December 24, 1784. In a memorial lecture delivered on 13 December 1965 at
UNESCO The United Nations Educational, Scientific and Cultural Organization is a specialized agency of the United Nations (UN) aimed at promoting world peace and security through international cooperation in education, arts, sciences and culture. It ...
headquarters, nuclear physicist J. Robert Oppenheimer summarized his impression of Einstein as a person: "He was almost wholly without sophistication and wholly without worldliness ... There was always with him a wonderful purity at once childlike and profoundly stubborn." Einstein bequeathed his personal archives, library, and intellectual assets to the
Hebrew University of Jerusalem The Hebrew University of Jerusalem (HUJI; he, הַאוּנִיבֶרְסִיטָה הַעִבְרִית בִּירוּשָׁלַיִם) is a public research university based in Jerusalem, Israel. Co-founded by Albert Einstein and Dr. Chaim Weiz ...
in Israel.


Scientific career

Throughout his life, Einstein published hundreds of books and articles. He published more than 300 scientific papers and 150 non-scientific ones. On 5 December 2014, universities and archives announced the release of Einstein's papers, comprising more than 30,000 unique documents. Einstein's intellectual achievements and originality have made the word "Einstein" synonymous with "genius". In addition to the work he did by himself he also collaborated with other scientists on additional projects including the Bose–Einstein statistics, the Einstein refrigerator and others.


1905 – ''Annus Mirabilis'' papers

The ''Annus Mirabilis'' papers are four articles pertaining to the photoelectric effect (which gave rise to
quantum theory Quantum theory may refer to: Science *Quantum mechanics, a major field of physics *Old quantum theory, predating modern quantum mechanics * Quantum field theory, an area of quantum mechanics that includes: ** Quantum electrodynamics ** Quantum ch ...
), Brownian motion, the
special theory of relativity In physics, the special theory of relativity, or special relativity for short, is a scientific theory regarding the relationship between Spacetime, space and time. In Albert Einstein's original treatment, the theory is based on two Postulates of ...
, and ''E'' = ''mc''2 that Einstein published in the ''Annalen der Physik'' scientific journal in 1905. These four works contributed substantially to the foundation of
modern physics Modern physics is a branch of physics that developed in the early 20th century and onward or branches greatly influenced by early 20th century physics. Notable branches of modern physics include quantum mechanics, special relativity and general ...
and changed views on
space Space is the boundless three-dimensional extent in which objects and events have relative position and direction. In classical physics, physical space is often conceived in three linear dimensions, although modern physicists usually consider ...
, time, and
matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic partic ...
. The four papers are:


Statistical mechanics


Thermodynamic fluctuations and statistical physics

Einstein's first paper submitted in 1900 to ''Annalen der Physik'' was on
capillary attraction Capillary action (sometimes called capillarity, capillary motion, capillary rise, capillary effect, or wicking) is the process of a liquid flowing in a narrow space without the assistance of, or even in opposition to, any external forces l ...
. It was published in 1901 with the title "Folgerungen aus den Capillaritätserscheinungen", which translates as "Conclusions from the capillarity phenomena". Two papers he published in 1902–1903 (thermodynamics) attempted to interpret
atom Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. Only the most common variety of hydrogen has no neutrons. Every solid, liquid, gas, and ...
ic phenomena from a statistical point of view. These papers were the foundation for the 1905 paper on Brownian motion, which showed that Brownian movement can be construed as firm evidence that molecules exist. His research in 1903 and 1904 was mainly concerned with the effect of finite atomic size on diffusion phenomena.


Theory of critical opalescence

Einstein returned to the problem of thermodynamic fluctuations, giving a treatment of the density variations in a fluid at its critical point. Ordinarily the density fluctuations are controlled by the second derivative of the free energy with respect to the density. At the critical point, this derivative is zero, leading to large fluctuations. The effect of density fluctuations is that light of all wavelengths is scattered, making the fluid look milky white. Einstein relates this to Rayleigh scattering, which is what happens when the fluctuation size is much smaller than the wavelength, and which explains why the sky is blue. Einstein quantitatively derived critical opalescence from a treatment of density fluctuations, and demonstrated how both the effect and Rayleigh scattering originate from the atomistic constitution of matter.


Special relativity

Einstein's "" ("On the Electrodynamics of Moving Bodies") was received on 30 June 1905 and published 26 September of that same year. It reconciled conflicts between
Maxwell's equations Maxwell's equations, or Maxwell–Heaviside equations, are a set of coupled partial differential equations that, together with the Lorentz force law, form the foundation of classical electromagnetism, classical optics, and electric circuits. ...
(the laws of electricity and magnetism) and the laws of Newtonian mechanics by introducing changes to the laws of mechanics. Observationally, the effects of these changes are most apparent at high speeds (where objects are moving at speeds close to the
speed of light The speed of light in vacuum, commonly denoted , is a universal physical constant that is important in many areas of physics. The speed of light is exactly equal to ). According to the special theory of relativity, is the upper limit ...
). The theory developed in this paper later became known as Einstein's special theory of relativity. This paper predicted that, when measured in the frame of a relatively moving observer, a clock carried by a moving body would appear to slow down, and the body itself would
contract A contract is a legally enforceable agreement between two or more parties that creates, defines, and governs mutual rights and obligations between them. A contract typically involves the transfer of goods, services, money, or a promise to tran ...
in its direction of motion. This paper also argued that the idea of a luminiferous aether—one of the leading theoretical entities in physics at the time—was superfluous. In his paper on
mass–energy equivalence In physics, mass–energy equivalence is the relationship between mass and energy in a system's rest frame, where the two quantities differ only by a multiplicative constant and the units of measurement. The principle is described by the physicis ...
, Einstein produced ''E'' = ''mc''2 as a consequence of his special relativity equations. Einstein's 1905 work on relativity remained controversial for many years, but was accepted by leading physicists, starting with Max Planck. Einstein originally framed special relativity in terms of
kinematics Kinematics is a subfield of physics, developed in classical mechanics, that describes the Motion (physics), motion of points, Physical object, bodies (objects), and systems of bodies (groups of objects) without considering the forces that cause ...
(the study of moving bodies). In 1908,
Hermann Minkowski Hermann Minkowski (; ; 22 June 1864 – 12 January 1909) was a German mathematician and professor at Königsberg, Zürich and Göttingen. He created and developed the geometry of numbers and used geometrical methods to solve problems in number t ...
reinterpreted special relativity in geometric terms as a theory of
spacetime In physics, spacetime is a mathematical model that combines the three dimensions of space and one dimension of time into a single four-dimensional manifold. Spacetime diagrams can be used to visualize relativistic effects, such as why differen ...
. Einstein adopted Minkowski's formalism in his 1915 general theory of relativity.


General relativity


General relativity and the equivalence principle

General relativity General relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics ...
(GR) is a
theory of gravitation In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the strong ...
that was developed by Einstein between 1907 and 1915. According to it, the observed gravitational attraction between masses results from the warping of
spacetime In physics, spacetime is a mathematical model that combines the three dimensions of space and one dimension of time into a single four-dimensional manifold. Spacetime diagrams can be used to visualize relativistic effects, such as why differen ...
by those masses. General relativity has developed into an essential tool in modern
astrophysics Astrophysics is a science that employs the methods and principles of physics and chemistry in the study of astronomical objects and phenomena. As one of the founders of the discipline said, Astrophysics "seeks to ascertain the nature of the h ...
; it provides the foundation for the current understanding of
black holes A black hole is a region of spacetime where gravity is so strong that nothing, including light or other electromagnetic waves, has enough energy to escape it. The theory of general relativity predicts that a sufficiently compact mass can def ...
, regions of space where gravitational attraction is so strong that not even light can escape. As Einstein later said, the reason for the development of general relativity was that the preference of inertial motions within
special relativity In physics, the special theory of relativity, or special relativity for short, is a scientific theory regarding the relationship between space and time. In Albert Einstein's original treatment, the theory is based on two postulates: # The laws o ...
was unsatisfactory, while a theory which from the outset prefers no state of motion (even accelerated ones) should appear more satisfactory. Consequently, in 1907 he published an article on acceleration under special relativity. In that article titled "On the Relativity Principle and the Conclusions Drawn from It", he argued that free fall is really inertial motion, and that for a free-falling observer the rules of special relativity must apply. This argument is called the
equivalence principle In the theory of general relativity, the equivalence principle is the equivalence of gravitational and inertial mass, and Albert Einstein's observation that the gravitational "force" as experienced locally while standing on a massive body (suc ...
. In the same article, Einstein also predicted the phenomena of gravitational time dilation, gravitational redshift and
gravitational lensing A gravitational lens is a distribution of matter (such as a galaxy cluster, cluster of galaxies) between a distant light source and an observer that is capable of bending the light from the source as the light travels toward the observer. This ...
. In 1911, Einstein published another article "On the Influence of Gravitation on the Propagation of Light" expanding on the 1907 article, in which he estimated the amount of deflection of light by massive bodies. Thus, the theoretical prediction of general relativity could for the first time be tested experimentally.


Gravitational waves

In 1916, Einstein predicted
gravitational wave Gravitational waves are waves of the intensity of gravity generated by the accelerated masses of an orbital binary system that propagate as waves outward from their source at the speed of light. They were first proposed by Oliver Heaviside in 1 ...
s, ripples in the
curvature In mathematics, curvature is any of several strongly related concepts in geometry. Intuitively, the curvature is the amount by which a curve deviates from being a straight line, or a surface deviates from being a plane. For curves, the canonic ...
of spacetime which propagate as
wave In physics, mathematics, and related fields, a wave is a propagating dynamic disturbance (change from equilibrium) of one or more quantities. Waves can be periodic, in which case those quantities oscillate repeatedly about an equilibrium (res ...
s, traveling outward from the source, transporting energy as gravitational radiation. The existence of gravitational waves is possible under general relativity due to its
Lorentz invariance In a relativistic theory of physics, a Lorentz scalar is an expression, formed from items of the theory, which evaluates to a scalar, invariant under any Lorentz transformation. A Lorentz scalar may be generated from e.g., the scalar product of ve ...
which brings the concept of a finite speed of propagation of the physical interactions of gravity with it. By contrast, gravitational waves cannot exist in the Newtonian theory of gravitation, which postulates that the physical interactions of gravity propagate at infinite speed. The first, indirect, detection of gravitational waves came in the 1970s through observation of a pair of closely orbiting
neutron stars A neutron star is the collapsed core of a massive supergiant star, which had a total mass of between 10 and 25 solar masses, possibly more if the star was especially metal-rich. Except for black holes and some hypothetical objects (e.g. white ...
,
PSR B1913+16 PSR may refer to: Organizations * Pacific School of Religion, Berkeley, California, US * Palestinian Center for Policy and Survey Research * Physicians for Social Responsibility, US ;Political parties: * Revolutionary Socialist Party (Portugal) ( ...
. The explanation for the decay in their orbital period was that they were emitting gravitational waves. Einstein's prediction was confirmed on 11 February 2016, when researchers at LIGO published the first observation of gravitational waves, detected on Earth on 14 September 2015, nearly one hundred years after the prediction.


Hole argument and Entwurf theory

While developing general relativity, Einstein became confused about the gauge invariance in the theory. He formulated an argument that led him to conclude that a general relativistic field theory is impossible. He gave up looking for fully generally covariant tensor equations and searched for equations that would be invariant under general linear transformations only. In June 1913, the Entwurf ('draft') theory was the result of these investigations. As its name suggests, it was a sketch of a theory, less elegant and more difficult than general relativity, with the equations of motion supplemented by additional gauge fixing conditions. After more than two years of intensive work, Einstein realized that the
hole argument In general relativity, the hole argument is an apparent paradox that much troubled Albert Einstein while developing his famous field equations. Some philosophers of physics take the argument to raise a problem for '' manifold substantialism'', a ...
was mistaken and abandoned the theory in November 1915.


Physical cosmology

In 1917, Einstein applied the general theory of relativity to the structure of the universe as a whole. He discovered that the general field equations predicted a universe that was dynamic, either contracting or expanding. As observational evidence for a dynamic universe was lacking at the time, Einstein introduced a new term, the cosmological constant, into the field equations, in order to allow the theory to predict a static universe. The modified field equations predicted a static universe of closed curvature, in accordance with Einstein's understanding of Mach's principle in these years. This model became known as the Einstein World or
Einstein's static universe Einstein's static universe, aka the Einstein universe or the Einstein static eternal universe, is a relativistic model of the universe proposed by Albert Einstein in 1917. Shortly after completing the general theory of relativity, Einstein applied ...
. Following the discovery of the recession of the galaxies by
Edwin Hubble Edwin Powell Hubble (November 20, 1889 – September 28, 1953) was an Americans, American astronomer. He played a crucial role in establishing the fields of extragalactic astronomy and observational cosmology. Hubble proved that many objects ...
in 1929, Einstein abandoned his static model of the universe, and proposed two dynamic models of the cosmos, the
Friedmann–Einstein universe The Friedmann–Einstein universe is a model of the universe published by Albert Einstein in 1931. The model is of historic significance as the first scientific publication in which Einstein embraced the possibility of a cosmos of time-varying radiu ...
of 1931 and the
Einstein–de Sitter universe The Einstein–de Sitter universe is a model of the universe proposed by Albert Einstein and Willem de Sitter in 1932. On first learning of Edwin Hubble's discovery of a linear relation between the redshift of the galaxies and their distance, Eins ...
of 1932. In each of these models, Einstein discarded the cosmological constant, claiming that it was "in any case theoretically unsatisfactory". In many Einstein biographies, it is claimed that Einstein referred to the cosmological constant in later years as his "biggest blunder", based on a letter
George Gamow George Gamow (March 4, 1904 – August 19, 1968), born Georgiy Antonovich Gamov ( uk, Георгій Антонович Гамов, russian: Георгий Антонович Гамов), was a Russian-born Soviet and American polymath, theoreti ...
claimed to have received from him. The astrophysicist
Mario Livio Mario Livio (born June 19, 1945) is an Israeli-American astrophysicist and an author of works that popularize science and mathematics. For 24 years (1991-2015) he was an astrophysicist at the Space Telescope Science Institute, which operates th ...
has cast doubt on this claim. In late 2013, a team led by the Irish physicist
Cormac O'Raifeartaigh Cormac O'Raifeartaigh (Cormac O'Rafferty) is an Irish physicist based at Waterford Institute of Technology in Ireland. A solid-state physicist by training, he is best known for several contributions to the study of the history and philosophy of ...
discovered evidence that, shortly after learning of Hubble's observations of the recession of the galaxies, Einstein considered a
steady-state model In cosmology, the steady-state model, or steady state theory is an alternative to the Big Bang theory of evolution of the universe. In the steady-state model, the density of matter in the expanding universe remains unchanged due to a continuou ...
of the universe. In a hitherto overlooked manuscript, apparently written in early 1931, Einstein explored a model of the expanding universe in which the density of matter remains constant due to a continuous creation of matter, a process that he associated with the cosmological constant. As he stated in the paper, "In what follows, I would like to draw attention to a solution to equation (1) that can account for Hubbel's 'sic''facts, and in which the density is constant over time" ... "If one considers a physically bounded volume, particles of matter will be continually leaving it. For the density to remain constant, new particles of matter must be continually formed in the volume from space." It thus appears that Einstein considered a
steady-state model In cosmology, the steady-state model, or steady state theory is an alternative to the Big Bang theory of evolution of the universe. In the steady-state model, the density of matter in the expanding universe remains unchanged due to a continuou ...
of the expanding universe many years before Hoyle, Bondi and Gold. However, Einstein's steady-state model contained a fundamental flaw and he quickly abandoned the idea.


Energy momentum pseudotensor

General relativity includes a dynamical spacetime, so it is difficult to see how to identify the conserved energy and momentum. Noether's theorem allows these quantities to be determined from a Lagrangian with
translation invariance In geometry, to translate a geometric figure is to move it from one place to another without rotating it. A translation "slides" a thing by . In physics and mathematics, continuous translational symmetry is the invariance of a system of equatio ...
, but
general covariance In theoretical physics, general covariance, also known as diffeomorphism covariance or general invariance, consists of the invariance of the ''form'' of physical laws under arbitrary differentiable coordinate transformations. The essential idea is ...
makes translation invariance into something of a
gauge symmetry In physics, a gauge theory is a type of field theory in which the Lagrangian (and hence the dynamics of the system itself) does not change (is invariant) under local transformations according to certain smooth families of operations (Lie groups) ...
. The energy and momentum derived within general relativity by Noether's prescriptions do not make a real tensor for this reason. Einstein argued that this is true for a fundamental reason: the gravitational field could be made to vanish by a choice of coordinates. He maintained that the non-covariant energy momentum pseudotensor was, in fact, the best description of the energy momentum distribution in a gravitational field. While the use of non-covariant objects like pseudotensors was criticized by Erwin Schrödinger and others, Einstein's approach has been echoed by physicists including Lev Landau and Evgeny Lifshitz.


Wormholes

In 1935, Einstein collaborated with
Nathan Rosen Nathan Rosen (Hebrew: נתן רוזן; March 22, 1909 – December 18, 1995) was an American-Israeli physicist noted for his study on the structure of the hydrogen atom and his work with Albert Einstein and Boris Podolsky on entangled wave functio ...
to produce a model of a
wormhole A wormhole (Einstein-Rosen bridge) is a hypothetical structure connecting disparate points in spacetime, and is based on a special Solutions of the Einstein field equations, solution of the Einstein field equations. A wormhole can be visualize ...
, often called
Einstein–Rosen bridges A wormhole (Einstein-Rosen bridge) is a hypothetical structure connecting disparate points in spacetime, and is based on a special Solutions of the Einstein field equations, solution of the Einstein field equations. A wormhole can be visualize ...
. His motivation was to model elementary particles with charge as a solution of gravitational field equations, in line with the program outlined in the paper "Do Gravitational Fields play an Important Role in the Constitution of the Elementary Particles?". These solutions cut and pasted
Schwarzschild black hole In Einstein's theory of general relativity, the Schwarzschild metric (also known as the Schwarzschild solution) is an exact solution to the Einstein field equations that describes the gravitational field outside a spherical mass, on the assumpti ...
s to make a bridge between two patches. Because these solutions included spacetime curvature without the presence of a physical body, Einstein and Rosen suggested that they could provide the beginnings of a theory that avoided the notion of point particles. However, it was later found that Einstein–Rosen bridges are not stable.


Einstein–Cartan theory

In order to incorporate spinning point particles into general relativity, the affine connection needed to be generalized to include an antisymmetric part, called the torsion. This modification was made by Einstein and Cartan in the 1920s.


Equations of motion

In general relativity, gravitational force is reimagined as curvature of
spacetime In physics, spacetime is a mathematical model that combines the three dimensions of space and one dimension of time into a single four-dimensional manifold. Spacetime diagrams can be used to visualize relativistic effects, such as why differen ...
. A curved path like an orbit is not the result of a force deflecting a body from an ideal straight-line path, but rather the body's attempt to fall freely through a background that is itself curved by the presence of other masses. A remark by John Archibald Wheeler that has become proverbial among physicists summarizes the theory: "Spacetime tells matter how to move; matter tells spacetime how to curve." The Einstein field equations cover the latter aspect of the theory, relating the curvature of spacetime to the distribution of matter and energy. The
geodesic equation In geometry, a geodesic () is a curve representing in some sense the shortest path ( arc) between two points in a surface, or more generally in a Riemannian manifold. The term also has meaning in any differentiable manifold with a connection ...
covers the former aspect, stating that freely falling bodies follow lines that are as straight as possible in a curved spacetime. Einstein regarded this as an "independent fundamental assumption" that had to be postulated in addition to the field equations in order to complete the theory. Believing this to be a shortcoming in how general relativity was originally presented, he wished to derive it from the field equations themselves. Since the equations of general relativity are non-linear, a lump of energy made out of pure gravitational fields, like a black hole, would move on a trajectory which is determined by the Einstein field equations themselves, not by a new law. Accordingly, Einstein proposed that the field equations would determine the path of a singular solution, like a black hole, to be a geodesic. Both physicists and philosophers have often repeated the assertion that the geodesic equation can be obtained from applying the field equations to the motion of a gravitational singularity, but this claim remains disputed.


Old quantum theory


Photons and energy quanta

In a 1905 paper, Einstein postulated that light itself consists of localized particles ('' quanta''). Einstein's light quanta were nearly universally rejected by all physicists, including Max Planck and Niels Bohr. This idea only became universally accepted in 1919, with
Robert Millikan Robert Andrews Millikan (March 22, 1868 – December 19, 1953) was an American experimental physicist honored with the Nobel Prize for Physics in 1923 for the measurement of the elementary electric charge and for his work on the photoelectric e ...
's detailed experiments on the photoelectric effect, and with the measurement of Compton scattering. Einstein concluded that each wave of frequency ''f'' is associated with a collection of photons with energy ''hf'' each, where ''h'' is the
Planck constant The Planck constant, or Planck's constant, is a fundamental physical constant of foundational importance in quantum mechanics. The constant gives the relationship between the energy of a photon and its frequency, and by the mass-energy equivale ...
. He did not say much more, because he was not sure how the particles were related to the wave. But he did suggest that this idea would explain certain experimental results, notably the photoelectric effect.


Quantized atomic vibrations

In 1907, Einstein proposed a model of matter where each atom in a lattice structure is an independent harmonic oscillator. In the Einstein model, each atom oscillates independently—a series of equally spaced quantized states for each oscillator. Einstein was aware that getting the frequency of the actual oscillations would be difficult, but he nevertheless proposed this theory because it was a particularly clear demonstration that quantum mechanics could solve the specific heat problem in classical mechanics.
Peter Debye Peter Joseph William Debye (; ; March 24, 1884 – November 2, 1966) was a Dutch-American physicist and physical chemist, and Nobel laureate in Chemistry. Biography Early life Born Petrus Josephus Wilhelmus Debije in Maastricht, Netherlands, D ...
refined this model.


Bose–Einstein statistics

In 1924, Einstein received a description of a
statistical Statistics (from German: ''Statistik'', "description of a state, a country") is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of data. In applying statistics to a scientific, industria ...
model from Indian physicist
Satyendra Nath Bose Satyendra Nath Bose (; 1 January 1894 – 4 February 1974) was a Bengali mathematician and physicist specializing in theoretical physics. He is best known for his work on quantum mechanics in the early 1920s, in developing the foundation for ...
, based on a counting method that assumed that light could be understood as a gas of indistinguishable particles. Einstein noted that Bose's statistics applied to some atoms as well as to the proposed light particles, and submitted his translation of Bose's paper to the ''
Zeitschrift für Physik ''Zeitschrift für Physik'' (English: ''Journal for Physics'') is a defunct series of German peer-reviewed physics journals established in 1920 by Springer Berlin Heidelberg. The series stopped publication in 1997, when it merged with other journ ...
''. Einstein also published his own articles describing the model and its implications, among them the Bose–Einstein condensate phenomenon that some particulates should appear at very low temperatures. It was not until 1995 that the first such condensate was produced experimentally by Eric Allin Cornell and
Carl Wieman Carl Edwin Wieman (born March 26, 1951) is an American physicist and educationist at Stanford University, and currently the A.D White Professor at Large at Cornell University. In 1995, while at the University of Colorado Boulder, he and Eric All ...
using ultra-cooling equipment built at the
NIST The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical sci ...
JILA laboratory at the
University of Colorado at Boulder The University of Colorado Boulder (CU Boulder, CU, or Colorado) is a public research university in Boulder, Colorado. Founded in 1876, five months before Colorado became a state, it is the flagship university of the University of Colorado sys ...
. Bose–Einstein statistics are now used to describe the behaviors of any assembly of bosons. Einstein's sketches for this project may be seen in the Einstein Archive in the library of the Leiden University.


Wave–particle duality

Although the patent office promoted Einstein to Technical Examiner Second Class in 1906, he had not given up on academia. In 1908, he became a ''
Privatdozent ''Privatdozent'' (for men) or ''Privatdozentin'' (for women), abbreviated PD, P.D. or Priv.-Doz., is an academic title conferred at some European universities, especially in German-speaking countries, to someone who holds certain formal qualific ...
'' at the University of Bern. In "''Über die Entwicklung unserer Anschauungen über das Wesen und die Konstitution der Strahlung''" (" The Development of our Views on the Composition and Essence of Radiation"), on the quantization of light, and in an earlier 1909 paper, Einstein showed that Max Planck's energy quanta must have well-defined
momenta Momenta is an autonomous driving company headquartered in Beijing, China that aims to build the 'Brains' for autonomous vehicles. In December 2021, Momenta and BYD established a 100 million yuan ($15.7 million) joint venture to deploy autonomous ...
and act in some respects as independent, point-like particles. This paper introduced the ''photon'' concept (although the name ''photon'' was introduced later by
Gilbert N. Lewis Gilbert Newton Lewis (October 23 or October 25, 1875 – March 23, 1946) was an American physical chemist and a Dean of the College of Chemistry at University of California, Berkeley. Lewis was best known for his discovery of the covalent bond a ...
in 1926) and inspired the notion of
wave–particle duality Wave–particle duality is the concept in quantum mechanics that every particle or quantum entity may be described as either a particle or a wave. It expresses the inability of the classical concepts "particle" or "wave" to fully describe the ...
in quantum mechanics. Einstein saw this wave–particle duality in radiation as concrete evidence for his conviction that physics needed a new, unified foundation.


Zero-point energy

In a series of works completed from 1911 to 1913, Planck reformulated his 1900 quantum theory and introduced the idea of
zero-point energy Zero-point energy (ZPE) is the lowest possible energy that a quantum mechanical system may have. Unlike in classical mechanics, quantum systems constantly Quantum fluctuation, fluctuate in their lowest energy state as described by the Heisen ...
in his "second quantum theory". Soon, this idea attracted the attention of Einstein and his assistant
Otto Stern :''Otto Stern was also the pen name of German women's rights activist Louise Otto-Peters (1819–1895)''. Otto Stern (; 17 February 1888 – 17 August 1969) was a German-American physicist and Nobel laureate in physics. He was the second most n ...
. Assuming the energy of rotating diatomic molecules contains zero-point energy, they then compared the theoretical specific heat of hydrogen gas with the experimental data. The numbers matched nicely. However, after publishing the findings, they promptly withdrew their support, because they no longer had confidence in the correctness of the idea of zero-point energy.


Stimulated emission

In 1917, at the height of his work on relativity, Einstein published an article in ''Physikalische Zeitschrift'' that proposed the possibility of
stimulated emission Stimulated emission is the process by which an incoming photon of a specific frequency can interact with an excited atomic electron (or other excited molecular state), causing it to drop to a lower energy level. The liberated energy transfers to th ...
, the physical process that makes possible the
maser A maser (, an acronym for microwave amplification by stimulated emission of radiation) is a device that produces coherent electromagnetic waves through amplification by stimulated emission. The first maser was built by Charles H. Townes, Ja ...
and the
laser A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The fir ...
. This article showed that the statistics of absorption and emission of light would only be consistent with Planck's distribution law if the emission of light into a mode with n photons would be enhanced statistically compared to the emission of light into an empty mode. This paper was enormously influential in the later development of quantum mechanics, because it was the first paper to show that the statistics of atomic transitions had simple laws.


Matter waves

Einstein discovered Louis de Broglie's work and supported his ideas, which were received skeptically at first. In another major paper from this era, Einstein observed that de Broglie waves could explain the quantization rules of Bohr and Sommerfeld. This paper would inspire Schrödinger's work of 1926.


Quantum mechanics


Einstein's objections to quantum mechanics

Einstein played a major role in developing quantum theory, beginning with his 1905 paper on the photoelectric effect. However, he became displeased with modern quantum mechanics as it had evolved after 1925, despite its acceptance by other physicists. He was skeptical that the randomness of quantum mechanics was fundamental rather than the result of determinism, stating that God "is not playing at dice". Until the end of his life, he continued to maintain that quantum mechanics was incomplete.


Bohr versus Einstein

The Bohr–Einstein debates were a series of public disputes about quantum mechanics between Einstein and Niels Bohr, who were two of its founders. Their debates are remembered because of their importance to the
philosophy of science Philosophy of science is a branch of philosophy concerned with the foundations, methods, and implications of science. The central questions of this study concern what qualifies as science, the reliability of scientific theories, and the ultim ...
. Their debates would influence later interpretations of quantum mechanics.


Einstein–Podolsky–Rosen paradox

Einstein never fully accepted quantum mechanics. While he recognized that it made correct predictions, he believed a more fundamental description of nature must be possible. Over the years he presented multiple arguments to this effect, but the one he preferred most dated to a debate with Bohr in 1930. Einstein suggested a
thought experiment A thought experiment is a hypothetical situation in which a hypothesis, theory, or principle is laid out for the purpose of thinking through its consequences. History The ancient Greek ''deiknymi'' (), or thought experiment, "was the most anci ...
in which two objects are allowed to interact and then moved apart a great distance from each other. The quantum-mechanical description of the two objects is a mathematical entity known as a
wavefunction A wave function in quantum physics is a mathematical description of the quantum state of an isolated quantum system. The wave function is a complex-valued probability amplitude, and the probabilities for the possible results of measurements mad ...
. If the wavefunction that describes the two objects before their interaction is given, then the
Schrödinger equation The Schrödinger equation is a linear partial differential equation that governs the wave function of a quantum-mechanical system. It is a key result in quantum mechanics, and its discovery was a significant landmark in the development of the ...
provides the wavefunction that describes them after their interaction. But because of what would later be called quantum entanglement, measuring one object would lead to an instantaneous change of the wavefunction describing the other object, no matter how far away it is. Moreover, the choice of which measurement to perform upon the first object would affect what wavefunction could result for the second object. Einstein reasoned that no influence could propagate from the first object to the second instantaneously fast. Indeed, he argued, physics depends on being able to tell one thing apart from another, and such instantaneous influences would call that into question. Because the true "physical condition" of the second object could not be immediately altered by an action done to the first, Einstein concluded, the wavefunction could not be that true physical condition, only an incomplete description of it. A more famous version of this argument came in 1935, when Einstein published a paper with Boris Podolsky and
Nathan Rosen Nathan Rosen (Hebrew: נתן רוזן; March 22, 1909 – December 18, 1995) was an American-Israeli physicist noted for his study on the structure of the hydrogen atom and his work with Albert Einstein and Boris Podolsky on entangled wave functio ...
that laid out what would become known as the
EPR paradox EPR may refer to: Science and technology * EPR (nuclear reactor), European Pressurised-Water Reactor * EPR paradox (Einstein–Podolsky–Rosen paradox), in physics * Earth potential rise, in electrical engineering * East Pacific Rise, a mid-ocea ...
. In this thought experiment, two particles interact in such a way that the wavefunction describing them is entangled. Then, no matter how far the two particles were separated, a precise position measurement on one particle would imply the ability to predict, perfectly, the result of measuring the position of the other particle. Likewise, a precise momentum measurement of one particle would result in an equally precise prediction for of the momentum of the other particle, without needing to disturb the other particle in any way. They argued that no action taken on the first particle could instantaneously affect the other, since this would involve information being transmitted faster than light, which is forbidden by the
theory of relativity The theory of relativity usually encompasses two interrelated theories by Albert Einstein: special relativity and general relativity, proposed and published in 1905 and 1915, respectively. Special relativity applies to all physical phenomena in ...
. They invoked a principle, later known as the "EPR criterion of reality", positing that: "If, without in any way disturbing a system, we can predict with certainty (i.e., with
probability Probability is the branch of mathematics concerning numerical descriptions of how likely an Event (probability theory), event is to occur, or how likely it is that a proposition is true. The probability of an event is a number between 0 and ...
equal to unity) the value of a physical quantity, then there exists an element of reality corresponding to that quantity." From this, they inferred that the second particle must have a definite value of both position and of momentum prior to either quantity being measured. But quantum mechanics considers these two observables incompatible and thus does not associate simultaneous values for both to any system. Einstein, Podolsky, and Rosen therefore concluded that quantum theory does not provide a complete description of reality. In 1964, John Stewart Bell carried the analysis of quantum entanglement much further. He deduced that if measurements are performed independently on the two separated particles of an entangled pair, then the assumption that the outcomes depend upon hidden variables within each half implies a mathematical constraint on how the outcomes on the two measurements are correlated. This constraint would later be called a Bell inequality. Bell then showed that quantum physics predicts correlations that violate this inequality. Consequently, the only way that hidden variables could explain the predictions of quantum physics is if they are "nonlocal", which is to say that somehow the two particles are able to interact instantaneously no matter how widely they ever become separated. Bell argued that because an explanation of quantum phenomena in terms of hidden variables would require nonlocality, the EPR paradox "is resolved in the way which Einstein would have liked least". Despite this, and although Einstein personally found the argument in the EPR paper overly complicated, that paper became among the most influential papers published in ''
Physical Review ''Physical Review'' is a peer-reviewed scientific journal established in 1893 by Edward Nichols. It publishes original research as well as scientific and literature reviews on all aspects of physics. It is published by the American Physical S ...
''. It is considered a centerpiece of the development of quantum information theory.


Unified field theory

Encouraged by his success with general relativity, Einstein sought an even more ambitious geometrical theory that would treat gravitation and electromagnetism as aspects of a single entity. In 1950, he described his
unified field theory In physics, a unified field theory (UFT) is a type of field theory that allows all that is usually thought of as fundamental forces and elementary particles to be written in terms of a pair of physical and virtual fields. According to the modern ...
in a ''
Scientific American ''Scientific American'', informally abbreviated ''SciAm'' or sometimes ''SA'', is an American popular science magazine. Many famous scientists, including Albert Einstein and Nikola Tesla, have contributed articles to it. In print since 1845, it i ...
'' article titled "On the Generalized Theory of Gravitation". His attempt to find the most fundamental laws of nature won him praise but not success: a particularly conspicuous blemish of his model was that it did not accommodate the
strong Strong may refer to: Education * The Strong, an educational institution in Rochester, New York, United States * Strong Hall (Lawrence, Kansas), an administrative hall of the University of Kansas * Strong School, New Haven, Connecticut, United Sta ...
and
weak nuclear force In nuclear physics and particle physics, the weak interaction, which is also often called the weak force or weak nuclear force, is one of the four known fundamental interactions, with the others being electromagnetism, the strong interaction, ...
s, neither of which was well understood until many years after his death. Although most researchers now believe that Einstein's approach to unifying physics was mistaken, his goal of a theory of everything is one to which his successors still aspire.


Other investigations

Einstein conducted other investigations that were unsuccessful and abandoned. These pertain to
force In physics, a force is an influence that can change the motion of an object. A force can cause an object with mass to change its velocity (e.g. moving from a state of rest), i.e., to accelerate. Force can also be described intuitively as a p ...
,
superconductivity Superconductivity is a set of physical properties observed in certain materials where electrical resistance vanishes and magnetic flux fields are expelled from the material. Any material exhibiting these properties is a superconductor. Unlike ...
, and other research.


Collaboration with other scientists

In addition to longtime collaborators
Leopold Infeld Leopold Infeld (20 August 1898 – 15 January 1968) was a Polish physicist who worked mainly in Poland and Canada (1938–1950). He was a Rockefeller fellow at Cambridge University (1933–1934) and a member of the Polish Academy of Sciences. Ea ...
,
Nathan Rosen Nathan Rosen (Hebrew: נתן רוזן; March 22, 1909 – December 18, 1995) was an American-Israeli physicist noted for his study on the structure of the hydrogen atom and his work with Albert Einstein and Boris Podolsky on entangled wave functio ...
,
Peter Bergmann Peter Gabriel Bergmann (24 March 1915 – 19 October 2002) was a German-American physicist best known for his work with Albert Einstein on a unified field theory encompassing all physical interactions. He also introduced primary and secondar ...
and others, Einstein also had some one-shot collaborations with various scientists.


Einstein–de Haas experiment

In 1908,
Owen Willans Richardson Sir Owen Willans Richardson, FRS (26 April 1879 – 15 February 1959) was a British physicist who won the Nobel Prize in Physics in 1928 for his work on thermionic emission, which led to Richardson's law. Biography Richardson was born in Dews ...
predicted that a change in the
magnetic moment In electromagnetism, the magnetic moment is the magnetic strength and orientation of a magnet or other object that produces a magnetic field. Examples of objects that have magnetic moments include loops of electric current (such as electromagnets ...
of a free body will cause this body to rotate. This effect is a consequence of the
conservation of angular momentum In physics, angular momentum (rarely, moment of momentum or rotational momentum) is the rotational analog of linear momentum. It is an important physical quantity because it is a conserved quantity—the total angular momentum of a closed system ...
and is strong enough to be observable in ferromagnetic materials. Einstein and
Wander Johannes de Haas Wander Johannes de Haas (2 March 1878 – 26 April 1960) was a Dutch physicist and mathematician. He is best known for the Shubnikov–de Haas effect, the De Haas–Van Alphen effect and the Einstein–de Haas effect. Personal life Wander de H ...
published two papers in 1915 claiming the first experimental observation of the effect. Measurements of this kind demonstrate that the phenomenon of
magnetization In classical electromagnetism, magnetization is the vector field that expresses the density of permanent or induced magnetic dipole moments in a magnetic material. Movement within this field is described by direction and is either Axial or Di ...
is caused by the alignment ( polarization) of the angular momenta of the
electron The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no kn ...
s in the material along the axis of magnetization. These measurements also allow the separation of the two contributions to the magnetization: that which is associated with the
spin Spin or spinning most often refers to: * Spinning (textiles), the creation of yarn or thread by twisting fibers together, traditionally by hand spinning * Spin, the rotation of an object around a central axis * Spin (propaganda), an intentionally b ...
and with the orbital motion of the electrons. The Einstein-de Haas experiment is the only experiment concived, realized and published by Albert Einstein himself. A complete original version of the Einstein-de Haas experimental equipment was donated by
Geertruida de Haas-Lorentz Geertruida Luberta de Haas-Lorentz (20 November 1885 – 1973) was a Dutch physicist and the first to perform fluctuational analysis of electrons as Brownian particles. Consequently she is considered to be the first woman to work in electrical no ...
, wife of de Haas and daughter of Lorentz, to the Ampère Museum in Lyon France in 1961 where it is currently on display. It was lost among the museum's holdings and was rediscovered in 2023.


Einstein as an inventor

In 1926, Einstein and his former student Leó Szilárd co-invented (and in 1930, patented) the Einstein refrigerator. This absorption refrigerator was then revolutionary for having no moving parts and using only heat as an input. On 11 November 1930, was awarded to Einstein and Leó Szilárd for the refrigerator. Their invention was not immediately put into commercial production, but the most promising of their patents were acquired by the Swedish company Electrolux. Einstein also invented an electromagnetic pump, sound reproduction device, and several other household devices.


Non-scientific legacy

While traveling, Einstein wrote daily to his wife Elsa and adopted stepdaughters Margot and Ilse. The letters were included in the papers bequeathed to the
Hebrew University of Jerusalem The Hebrew University of Jerusalem (HUJI; he, הַאוּנִיבֶרְסִיטָה הַעִבְרִית בִּירוּשָׁלַיִם) is a public research university based in Jerusalem, Israel. Co-founded by Albert Einstein and Dr. Chaim Weiz ...
. Margot Einstein permitted the personal letters to be made available to the public, but requested that it not be done until twenty years after her death (she died in 1986). Barbara Wolff, of the Hebrew University's
Albert Einstein Archives Albert Einstein Archives refers to an archive on the Givat Ram ( Edmond J. Safra) campus of the Hebrew University of Jerusalem in Jerusalem, Israel housing the personal papers of 20th century physicist Albert Einstein. Overview In his will, Alb ...
, told the
BBC #REDIRECT BBC #REDIRECT BBC #REDIRECT BBC Here i going to introduce about the best teacher of my life b BALAJI sir. He is the precious gift that I got befor 2yrs . How has helped and thought all the concept and made my success in the 10th board ex ...
that there are about 3,500 pages of private correspondence written between 1912 and 1955. Einstein's
right of publicity Personality rights, sometimes referred to as the right of publicity, are rights for an individual to control the commercial use of their identity, such as name, image, likeness, or other unequivocal identifiers. They are generally considered as ...
was litigated in 2015 in a federal district court in California. Although the court initially held that the right had expired, that ruling was immediately appealed, and the decision was later vacated in its entirety. The underlying claims between the parties in that lawsuit were ultimately settled. The right is enforceable, and the Hebrew University of Jerusalem is the exclusive representative of that right. Corbis, successor to The Roger Richman Agency, licenses the use of his name and associated imagery, as agent for the university. Mount Einstein in the
Chugach Mountains The Chugach Mountains of southern Alaska are the northernmost of the several mountain ranges that make up the Pacific Coast Ranges of the western edge of North America. The range is about long and wide, and extends from the Knik and Turnagain ...
of
Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...
was named in 1955. Mount Einstein in New Zealand's
Paparoa Range The Paparoa Range is a mountain range in the West Coast Region, West Coast region of New Zealand's South Island. It was the first New Zealand land seen by a European – Abel Tasman in 1642. Part of the range has the country's highest protection ...
was named after him in 1970 by the
Department of Scientific and Industrial Research Department of Scientific and Industrial Research, abbreviated DSIR was the name of several British Empire organisations founded after the 1923 Imperial Conference to foster intra-Empire trade and development. * Department of Scientific and Industria ...
.


In popular culture

Einstein became one of the most famous scientific celebrities after the confirmation of his general theory of relativity in 1919. Although most of the public had little understanding of his work, he was widely recognized and admired. In the period before World War II, ''
The New Yorker ''The New Yorker'' is an American weekly magazine featuring journalism, commentary, criticism, essays, fiction, satire, cartoons, and poetry. Founded as a weekly in 1925, the magazine is published 47 times annually, with five of these issues ...
'' published a vignette in their "The Talk of the Town" feature saying that Einstein was so well known in America that he would be stopped on the street by people wanting him to explain "that theory". Eventually he came to cope with unwanted enquirers by pretending to be someone else: "Pardon me, sorry! Always I am mistaken for Professor Einstein." Einstein has been the subject of or inspiration for many novels, films, plays, and works of music. He is a favorite model for depictions of
absent-minded professor The absent-minded professor is a stock character of popular fiction, usually portrayed as a talented academic whose academic brilliance is accompanied by below-par functioning in other areas, leading to forgetfulness and mistakes. One explanati ...
s; his expressive face and distinctive hairstyle have been widely copied and exaggerated. ''
Time Time is the continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, into the future. It is a component quantity of various measurements used to sequence events, to ...
'' magazine's Frederic Golden wrote that Einstein was "a cartoonist's dream come true". Many popular
quotations A quotation is the repetition of a sentence, phrase, or passage from speech or text that someone has said or written. In oral speech, it is the representation of an utterance (i.e. of something that a speaker actually said) that is introduced by ...
are often misattributed to him.


Awards and honors

Einstein received numerous awards and honors, and in 1922, he was awarded the 1921
Nobel Prize in Physics ) , image = Nobel Prize.png , alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then " ...
"for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect". None of the nominations in 1921 met the criteria set by
Alfred Nobel Alfred Bernhard Nobel ( , ; 21 October 1833 – 10 December 1896) was a Swedes, Swedish chemist, engineer, inventor, businessman, and Philanthropy, philanthropist. He is best known for having bequeathed his fortune to establish the Nobel ...
, so the 1921 prize was carried forward and awarded to Einstein in 1922. Einsteinium, a synthetic chemical element, was named in his honor in 1955, a few months after his death.


Publications


Scientific

: * * * * * * * * * * * * * First of a series of papers on this topic. * * * * * * * * * A reprint of this book was published by Edition Erbrich in 1982, . * Further information about the volumes published so far can be found on the webpages of the Einstein Papers Project and on the Princeton University Press Einstein Page.


Others

* * * Einstein, Albert (September 1960)
Foreword to ''Gandhi Wields the Weapon of Moral Power: Three Case Histories''.
Introduction by Bharatan Kumarappa. Ahmedabad: Navajivan Publishing House. pp. v–vi. . Foreword originally written in April 1953. * The ''chasing a light beam'' thought experiment is described on pages 48–51.


See also

*
Bern Historical Museum french: Musée d’Histoire de Berne , image = Historic museum Bern1.jpg , image_upright = , alt = , caption = The Museum entrance on Helvetiaplatz , map_type = Switzerland Bern dow ...
(Einstein Museum) *
Einstein notation In mathematics, especially the usage of linear algebra in Mathematical physics, Einstein notation (also known as the Einstein summation convention or Einstein summation notation) is a notational convention that implies summation over a set of ...
*
Frist Campus Center Frist Campus Center is a focal point of social life at Princeton University. The campus center is a combination of the former Palmer Physics Lab, and a modern addition completed in 2001. It was endowed with money from the fortune the Frist family ...
at
Princeton University Princeton University is a private university, private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth, New Jersey, Elizabeth as the College of New Jersey, Princeton is the List of Colonial Colleges, fourth-oldest ins ...
room 302 is associated with Einstein. The center was once the Palmer Physical Laboratory. *
Heinrich Burkhardt Heinrich Friedrich Karl Ludwig Burkhardt (15 October 1861 – 2 November 1914) was a German mathematician. He famously was one of the two examiners of Albert Einstein's PhD thesis ''Eine neue Bestimmung der Moleküldimensionen''. Of Einstein' ...
*
Heinrich Zangger Heinrich Zangger (born 6 December 1874, Bubikon – 15 March 1957, Zürich) was a Swiss toxicologist and coroner. He was one of the "foremost forensic scientists of his generation". Biography Zangger was the son of a prosperous farmer and studied ...
*
History of gravitational theory In physics, theories of gravitation postulate mechanisms of interaction governing the movements of bodies with mass. There have been numerous theories of gravitation since ancient times. The first extant sources discussing such theories are foun ...
*
List of coupled cousins This is a list of notable individuals who have been romantically or maritally coupled with a first cousin. Worldwide, more than 10% of marriages are between first or second cousins. Cousin marriage is an important topic in anthropology and allian ...
*
List of German inventors and discoverers ---- __NOTOC__ This is a list of German inventors and discoverers. The following list comprises people from Germany or German-speaking Europe, and also people of predominantly German heritage, in alphabetical order of the surname. For the li ...
*
List of Jewish Nobel laureates Nobel Prizes have been awarded to over 900 individuals, of whom at least 20% were Jews. * * * * * * * * The number of Jews receiving Nobel prizes has been the subject of some attention.* * *"Jews rank high among winners of Nobel, but why ...
*
List of peace activists This list of peace activists includes people who have proactively advocated diplomatic, philosophical, and non-military resolution of major territorial or ideological disputes through nonviolent means and methods. Peace activists usually work ...
*
Relativity priority dispute Albert Einstein presented the theories of special relativity and general relativity in publications that either contained no formal references to previous literature, or referred only to a small number of his predecessors for fundamental results ...
* Sticky bead argument


Notes


References


Works cited

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *


Further reading

* * * * * , or * * * * *


External links

* * * *
Einstein's Personal Correspondence: Religion, Politics, The Holocaust, and Philosophy
Shapell Manuscript Foundation
Federal Bureau of Investigation file on Albert Einstein

Einstein and his love of music
'' Physics World'' * including the Nobel Lecture 11 July 1923 ''Fundamental ideas and problems of the theory of relativity''
Albert Einstein Archives Online (80,000+ Documents)

MSNBC, 19 March 2012

Einstein's declaration of intention for American citizenship
on the
World Digital Library The World Digital Library (WDL) is an international digital library operated by UNESCO and the United States Library of Congress. The WDL has stated that its mission is to promote international and intercultural understanding, expand the volume ...

Albert Einstein Collection
at
Brandeis University , mottoeng = "Truth even unto its innermost parts" , established = , type = Private research university , accreditation = NECHE , president = Ronald D. Liebowitz , pro ...

The Collected Papers of Albert Einstein "Digital Einstein"
at
Princeton University Princeton University is a private university, private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth, New Jersey, Elizabeth as the College of New Jersey, Princeton is the List of Colonial Colleges, fourth-oldest ins ...
*
Home page of Albert Einstein at The Institute for Advanced Study

Albert – The Digital Repository of the IAS
which contains many digitized original documents and photographs * {{DEFAULTSORT:Einstein, Albert 1879 births 1955 deaths 19th-century German Jews 20th-century American engineers 20th-century American inventors 20th-century American male writers 20th-century American non-fiction writers 20th-century American physicists 20th-century Swiss inventors Academic staff of Charles University Academic staff of ETH Zurich Academic staff of the University of Bern Academic staff of the University of Zurich American agnostics American Ashkenazi Jews American democratic socialists American humanists American letter writers American male non-fiction writers American Nobel laureates American pacifists American relativity theorists American science writers American Zionists Anti-nationalists Deaths from abdominal aortic aneurysm Denaturalized citizens of Germany
Albert Albert may refer to: Companies * Albert (supermarket), a supermarket chain in the Czech Republic * Albert Heijn, a supermarket chain in the Netherlands * Albert Market, a street market in The Gambia * Albert Productions, a record label * Albert ...
ETH Zurich alumni European democratic socialists German agnostics German Ashkenazi Jews German emigrants to Switzerland German humanists German male non-fiction writers German Nobel laureates German relativity theorists German Zionists Institute for Advanced Study faculty Jewish agnostics Jewish American non-fiction writers Jewish American physicists Jewish German physicists Jewish emigrants from Nazi Germany to the United States Jewish scientists Jewish socialists Labor Zionists Max Planck Institute directors Members of the American Philosophical Society Members of the Royal Netherlands Academy of Arts and Sciences Members of the United States National Academy of Sciences Naturalised citizens of Austria Naturalised citizens of Switzerland Naturalized citizens of the United States Nobel laureates in Physics Pantheists Patent examiners People from Ulm People who lost German citizenship People with multiple nationality Philosophers of mathematics Philosophers of science Philosophy of science Quantum physicists Recipients of Franklin Medal Scientists from Munich Stateless people Swiss agnostics Swiss Ashkenazi Jews Swiss cosmologists Swiss emigrants to the United States Swiss Nobel laureates Swiss physicists University of Zurich alumni Winners of the Max Planck Medal Württemberger emigrants to the United States