Albert Einstein

Born

March 14, 1879, Ulm, Germany^[2]

Died

April 18, 1955, Princeton, New Jersey^[2]

Citizenship

Swiss from 1901, German again from 1914 until he renounced it in 1933, American from 1940^[1]

Known for

Special and general relativity, E=mc², light quanta, the explanation of Brownian motion^[4][6]

Nobel Prize

Physics, 1921 (received in 1922), for services to theoretical physics and the law of the photoelectric effect^[2]

Spouses

Mileva Marić (married 1903, dissolved 1919); Elsa Löwenthal (married 1919, died 1936)^[1]

Last post

Institute for Advanced Study, Princeton, from 1933; retired 1945^[1][2]

Early life and education

Einstein was born into a middle-class German Jewish family in Ulm, and within six weeks the family had moved to Munich, where his father ran an electrical engineering business and Albert started school.^[1][2][3] He quit high school at 15 in 1895 to join his relatives in Italy, then finished his schooling at Aarau in Switzerland.^[1][3] In 1896 he entered the federal polytechnic in Zurich, later known as ETH, to train as a teacher of physics and mathematics.^[1][2]

He finished with an undistinguished record and could not find a teaching job. The American Institute of Physics dates his graduation to 1900, the Nobel Foundation's biography his diploma to 1901, the same year he became a Swiss citizen.^[1][3] After about two years of odd jobs he joined the Swiss patent office in Bern as a clerk in 1902, and he stayed until 1909, reportedly on a 48-hour week.^[3][7] He married Mileva Marić, a former classmate, in 1903; they had a daughter and two sons.^[1][3][7]

The papers of 1905

Einstein did much of his early research in his spare time at the patent office, and from a rented flat at Kramgasse 49 he completed his best-known work between March and June 1905.^[1][7] That year, in which he turned 26, four papers appeared in the journal Annalen der Physik, and it is now often called his miracle year.^[6][7] He also earned his doctorate in 1905.^[1]

0:58 A newsreel on E = mc2 An old newsreel credits Einstein with defining the relation between matter and energy in 1905.

• Light quanta: he treated light as coming in discrete packets of energy, which accounted for the way light knocks electrons from metal.^[4][6]
• Brownian motion: he explained the jitter of tiny suspended particles as the result of molecular collisions, which gave strong support to the reality of atoms.^[4][6]
• Special relativity: by rethinking what time means, he squared the principle of relativity with electromagnetism, and the speed of light came out the same regardless of how its source moves.^[4][6]
• Mass and energy: a short follow-up showed that a body giving off energy loses a proportional amount of mass, the relation written E=mc².^[4][6]

Academic career and general relativity

Recognition brought a run of posts: lecturer in Bern in 1908, then professor at Zurich in 1909, at Prague in 1911, and at Zurich again in 1912.^[1] In 1914 he moved to Berlin to direct the Kaiser Wilhelm Physical Institute and hold a university chair that carried no teaching load, and he took German citizenship.^[1][3] He separated from his wife and sons at about this time, and he opposed Germany's aims in World War I by backing a pacifist group.^[3]

His attempt to extend relativity to gravity took roughly a decade. He completed the general theory in 1915 and published the full account in 1916.^[1][3] One prediction, that gravity bends the path of light, could be tested. Two British expeditions organized by Frank Dyson photographed stars during the solar eclipse of May 29, 1919, one at Sobral in Brazil and one, with Arthur Eddington, on the island of Príncipe.^[8] Focus trouble and a shortage of good plates limited the evidence, but on Nov. 6, 1919 a joint meeting of the Royal Society and the Royal Astronomical Society reported that the results supported Einstein's prediction.^[8] The British press covered the news eagerly, with The Times running extracts over the next two days.^[8] He had married Elsa Löwenthal, his cousin, that same year, after his first marriage was dissolved.^[1]

4:37 Mass curves space-time Science ABC's animation of the trampoline analogy for general relativity.

The Nobel committee's citation names his services to theoretical physics and especially the law of the photoelectric effect, not relativity.^[2] The 1921 prize was handed to him a year later, in 1922.^[2] Other honors included the Royal Society's Copley Medal in 1925 and the Franklin Institute's Franklin Medal in 1935.^[1]

Quantum theory and the search for unification

Einstein's light quanta helped start quantum physics, yet he never accepted the form the theory took. Niels Bohr and Werner Heisenberg argued that some atomic events, such as the moment an atom gives off light, cannot be predicted even in principle. He pressed the opposite case against Bohr at the Solvay conferences of 1927 and 1930, and neither gave way.^[5] By the mid-1930s he conceded the theory was consistent and very successful as a statistical description, but he still judged it incomplete. He wrote that God "is not playing at dice."^[5]

In 1935 he, Boris Podolsky and Nathan Rosen argued that quantum mechanics does not fully describe reality, a problem now known as the EPR paradox after their initials.^[13] Einstein spoke of entanglement, the link the theory implies between distant particles, as spooky action at a distance.^[13] Later experiments tested these ideas directly, and the 2022 Nobel Prize in Physics went to three researchers for such work with entangled photons.^[13]

From the 1920s until his death he pursued a unified field theory, a single framework built on the geometric approach of general relativity. He announced one in 1929, but its mathematics could not be checked against experiment, and most physicists were heading in a different direction.^[1][3][5] He was still working on the problem when he died.^[3]

Exile, the bomb and public life

When the Nazis took power in 1933, Einstein gave up his German citizenship and moved to the United States to join the Institute for Advanced Study in Princeton.^[1][2][3] He stepped back from strict pacifism, warned about German aggression, and helped rescue victims of the regime.^[3] Elsa died in 1936, and he became an American citizen in 1940.^[1]

3:35 Einstein speaks: "as a man, as a good European and as a Jew" Archival film of Einstein himself, thanking his hosts and declining to judge the nation that once called him its own.

On Aug. 2, 1939, at the urging of the Hungarian refugee physicists Leo Szilard, Eugene Wigner and Edward Teller, he signed a letter to President Franklin D. Roosevelt.^[10] It said a uranium chain reaction looked close to achievable, that it could yield bombs powerful enough to destroy a port, and that Germany had stopped selling uranium from the Czechoslovak mines it had seized; it urged the government to speed up research and secure ore.^[10] He took no part in the resulting Manhattan Project during World War II. His pacifist views cost him a security clearance in July 1940.^[9] He later expressed regret in an interview with Newsweek:^[9]

1:36 The letter to the president A period narrator on why Einstein wrote to the president in 1939, fearing Nazi Germany would be first to release atomic energy.

“had I known that the Germans would not succeed in developing an atomic bomb, I would have done nothing.”Albert Einstein

After the war he worked to control nuclear arms and was a prominent supporter of world government.^[1][9] He was offered the presidency of Israel and declined, having earlier helped Chaim Weizmann establish the Hebrew University of Jerusalem, for which he raised funds on a trip to America in 1921.^[1][3] He retired from his Princeton post in 1945.^[1] He is among the 11 signatories of the Russell-Einstein Manifesto, dated July 9, 1955, nearly three months after his death, which asked scientists and governments to face the danger of nuclear war and settle disputes peacefully.^[11]

1:59 "We scientists who released this immense power" The Emergency Committee of Atomic Scientists' appeal for funds, in a period film.

He died at Princeton on April 18, 1955, while still at work on unification, on a speech for Israel and on an anti-war project.^[2][3]

Legacy

The predictions of his theories have continued to be tested a century on. The laser reflector left on the Moon by Apollo 11 has yielded measurements consistent with general relativity.^[14] On Sept. 14, 2015 the LIGO detectors in the United States observed gravitational waves for the first time, produced by two black holes colliding, and they had taken 1.3 billion years to arrive. He had predicted such waves about 100 years earlier, and the work won the 2017 Nobel Prize in Physics.^[12]

His written record is still being published. The Collected Papers of Albert Einstein, produced by the Einstein Papers Project at Caltech with Princeton University Press, has reached 17 volumes and carries his life up to his first term at Caltech, with its online portal planning coverage through 1955.^[15][16] The project's Einstein Archives Online lists more than 90,000 records of known manuscripts and letters, and the papers draw on the Albert Einstein Archives at the Hebrew University.^[15][16]

Timeline

1. March 14, 1879 Born in Ulm.^[2]
2. 1896 Enters the federal polytechnic in Zurich.^[1]
3. 1902 Starts as a clerk at the Swiss patent office in Bern.^[7]
4. 1905 Publishes four landmark papers and earns his doctorate.^[1][6]
5. 1914 Moves to Berlin.^[1]
6. 1915 Completes the general theory of relativity.^[3]
7. May 29, 1919 Eclipse expeditions make the observations that support his prediction.^[8]
8. 1922 Receives the 1921 Nobel Prize in Physics.^[2]
9. 1933 Renounces German citizenship and goes to Princeton.^[1]
10. 1935 Publishes the EPR argument with Podolsky and Rosen.^[13]
11. Aug. 2, 1939 Signs the letter to President Roosevelt on uranium.^[10]
12. 1940 Becomes an American citizen.^[1]
13. April 18, 1955 Dies in Princeton.^[2]