Albert Einstein

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• Born: 14 March 1879
• Birthplace: Ulm, Germany
• Died: 18 April 1955 (heart failure)
• Best Known As: Creator of the theory of relativity

Thanks to his theory of relativity, Albert Einstein became the most famous scientist of the 20th century. In 1905, while working in a Swiss patent office, Einstein published a paper proposing a "special theory of relativity," a groundbreaking notion which laid the foundation for much of modern physics theory. (The theory included his famous equation e=mc².) Einstein's work had a profound impact on everything from quantum theory to nuclear power and the atom bomb. He continued to develop and refine his early ideas, and in 1915 published what is known as his general theory of relativity. By 1920 Einstein was internationally renowned; he won the Nobel Prize in 1921, not for relativity but for his 1905 work on the photoelectric effect. In 1933 Einstein moved to Princeton, New Jersey, where he worked at the Institute for Advanced Studies until the end of his life. Einstein's genius is often compared with that of Sir Isaac Newton; in 2000 Time magazine named him the leading figure of the 20th century.

Einstein was famously rumpled and frizzy-haired, and over time his image has become synonymous with absent-minded genius... He sent a famous letter to Franklin Roosevelt in 1939, warning that Germany was developing an atomic bomb and urging Allied research toward the same goal... Einstein married Mileva Maric in 1903. They had two sons: Hans Albert (b. 1904) and Eduard (b. 1910). They also had a daughter born before their marriage, Leiserl (b. 1902). She apparently was given for adoption or died in infancy. Mileva and Albert were divorced in 1914... He married his cousin Elsa Löwenthal in 1919, and they remained married until her death in 1936... The Institute for Advanced Studies has no formal link to Princeton University; however, according the IAS website, the two institutions "have many historic ties and ongoing relationships"... The Albert Einstein College of Medicine opened in New York City in 1955. It is part of Yeshiva University. Einstein did not create the school, but gave his permission to have his name used.

[b. Ulm, Germany, March 14, 1879, d. Princeton, New Jersey, April 18, 1955]

Einstein's contributions to physics began in 1905 with three major results: the explanation of Brownian motion in terms of molecules; the explanation of the photoelectric effect in terms of the quantum; and the special theory of relativity that links time to space and energy to matter. From 1907 to 1915 Einstein developed general relativity, a theory of gravity more accurate than Newton's; it became the basis of theoretical cosmology. In failed efforts in the 1930s to refute the interpretation of quantum theory in terms of probability, Einstein contributed to the theoretical basis for what is sometimes called teleportation of photons (which Einstein called "spooky action at a distance"). His last major effort was an attempt to unify electromagnetism and gravity into a single unified field theory, still an active problem of physics.

Einstein, Albert (1879-1955) theoretical physicist, born in Ulm, Germany. Einstein's 1939 letter to President Franklin D. Roosevelt urging that the United States develop an atomic bomb gave rise to the Manhattan Project. Einstein himself, however, played no role in that undertaking. He received the Nobel Prize in physics (1921) for his elaboration of the quantum theory.

See the Introduction, Abbreviations and Pronunciation for further details.

The German-born American physicist Albert Einstein (1879-1955) revolutionized the science of physics. He is best known for his theory of relativity.

In the history of the exact sciences, only a handful of men - men like Nicolaus Copernicus and Isaac Newton - share the honor that was Albert Einstein's: the initiation of a revolution in scientific thought. His insights into the nature of the physical world made it impossible for physicists and philosophers to view that world as they had before. When describing the achievements of other physicists, the tendency is to enumerate their major discoveries; when describing the achievements of Einstein, it is possible to say, simply, that he revolutionized physics.

Albert Einstein was born on March 14, 1879, in Ulm, but he grew up and obtained his early education in Munich. He was not a child prodigy; in fact, he was unable to speak fluently at age 9. Finding profound joy, liberation, and security in contemplating the laws of nature, already at age 5 he had experienced a deep feeling of wonder when puzzling over the invisible, yet definite, force directing the needle of a compass. Seven years later he experienced a different kind of wonder: the deep emotional stirring that accompanied his discovery of Euclidean geometry, with its lucid and certain proofs. Einstein mastered differential and integral calculus by age 16.

Education in Zurich

Einstein's formal secondary education was abruptly terminated at 16. He found life in school intolerable, and just as he was scheming to find a way to leave without impairing his chances for entering the university, his teacher expelled him for the negative effects his rebellious attitude was having on the morale of his classmates. Einstein tried to enter the Federal Institute of Technology (FIT) in Zurich, Switzerland, but his knowledge of nonmathematical disciplines was not equal to that of mathematics and he failed the entrance examination. On the advice of the principal, he thereupon first obtained his diploma at the Cantonal School in Aarau, and in 1896 he was automatically admitted into the FIT. There he came to realize that his deepest interest and facility lay in physics, both experimental and theoretical, rather than in mathematics.

Einstein passed his diploma examination at the FIT in 1900, but due to the opposition of one of his professors he was unable to subsequently obtain the usual university assistantship. In 1902 he was engaged as a technical expert, third-class, in the patent office in Bern, Switzerland. Six months later he married Mileva Maric, a former classmate in Zurich. They had two sons. It was in Bern, too, that Einstein, at 26, completed the requirements for his doctoral degree and wrote the first of his revolutionary scientific papers.

Academic Career

These papers made Einstein famous, and universities soon began competing for his services. In 1909, after serving as a lecturer at the University of Bern, Einstein was called as an associate professor to the University of Zurich. Two years later he was appointed a full professor at the German University in Prague. Within another year and a half Einstein became a full professor at the FIT. Finally, in 1913 the well-known scientists Max Planck and Walter Nernst traveled to Zurich to persuade Einstein to accept a lucrative research professorship at the University of Berlin, as well as full membership in the Prussian Academy of Science. He accepted their offer in 1914, quipping: "The Germans are gambling on me as they would on a prize hen. I do not really know myself whether I shall ever really lay another egg." When he went to Berlin, his wife remained behind in Zurich with their two sons; after their divorce he married his cousin Elsa in 1917.

In 1920 Einstein was appointed to a lifelong honorary visiting professorship at the University of Leiden. During 1921-1922 Einstein, accompanied by Chaim Weizmann, the future president of the state of Israel, undertook extensive worldwide travels in the cause of Zionism. In Germany the attacks on Einstein began. Philipp Lenard and Johannes Stark, both Nobel Prize-winning physicists, began characterizing Einstein's theory of relativity as "Jewish physics." This callousness and brutality increased until Einstein resigned from the Prussian Academy of Science in 1933. (He was, however, expelled from the Bavarian Academy of Science.)

Career in America

On several occasions Einstein had visited the California Institute of Technology, and on his last trip to the United States Abraham Flexner offered Einstein - on Einstein's terms - a position in the newly conceived and funded Institute for Advanced Studies in Princeton. He went there in 1933.

Einstein played a key role (1939) in mobilizing the resources necessary to construct the atomic bomb by signing a famous letter to President Franklin D. Roosevelt which had been drafted by Leo Szilard and E.P. Wigner. When Einstein's famous equation E mc² was finally demonstrated in the most awesome and terrifying way by using the bomb to destroy Hiroshima in 1945, Einstein, the pacifist and humanitarian, was deeply shocked and distressed; for a long time he could only utter "Horrible, horrible." On April 18, 1955, Einstein died in Princeton.

Theory of Brownian Motion

From numerous references in Einstein's writings it is evident that, of all areas in physics, thermodynamics made the deepest impression on him. During 1902-1904 Einstein reworked the foundations of thermodynamics and statistical mechanics; this work formed the immediate background to his revolutionary papers of 1905, one of which was on Brownian motion.

In Brownian motion (first observed in 1827 by the Scottish botanist Robert Brown), small particles suspended in a viscous liquid such as water undergo a rapid, irregular motion. Einstein, unaware of Brown's earlier observations, concluded from his theoretical studies that such a motion must exist. Guided by the thought that if the liquid in which the particles are suspended consists of atoms or molecules they should collide with the particles and set them into motion, he found that while the particle's motion is irregular, fluctuating back and forth, it will in time nevertheless experience a net forward displacement. Einstein proved that this net forward displacement of the suspended particles is directly related to the number of molecules per gram atomic weight. This point created a good deal of skepticism toward Einstein's theory at the time he developed it (1905-1906), but when it was fully confirmed many of the skeptics were converted. Brownian motion is to this day regarded as one of the most direct proofs of the existence of atoms.

Light Quanta and Wave-Particle Duality

The most common misconceptions concerning Einstein's introduction of his revolutionary light quantum (light particle) hypothesis in 1905 are that he simply applied Planck's quantum hypothesis of 1900 to radiation and that he introduced light quanta to "explain" the photoelectric effect discovered in 1887 by Heinrich Hertz and thoroughly investigated in 1902 by Philipp Lenard. Neither of these assertions is accurate. Einstein's arguments for his light quantum hypothesis - that under certain circumstances radiant energy (light) behaves as if it consists not of waves but of particles of energy proportional to their frequencies - were absolutely fundamental and, as in the case of his theory of Brownian motion, based on his own insights into the foundations of thermodynamics and statistical mechanics. Furthermore, it was only after presenting strong arguments for the necessity of his light quantum hypothesis that Einstein pursued its experimental consequences. One of several such consequences was the photoelectric effect, the experiment in which high-frequency ultraviolet light is used to eject electrons from thin metal plates. In particular, Einstein assumed that a single quantum of light transfers its entire energy to a single electron in the metal plate. The famous equation he derived was fully consistent with Lenard's observation that the energy of the ejected electrons depends only on the frequency of the ultraviolet light and not on its intensity. Einstein was not disturbed by the fact that this apparently contradicts James Clerk Maxwell's classic electromagnetic wave theory of light, because he realized that there were good reasons to doubt the universal validity of Maxwell's theory.

Although Einstein's famous equation for the photoelectric effect - for which he won the Nobel Prize of 1921 - appears so natural today, it was an extremely bold prediction in 1905. Not until a decade later did R.A. Millikan finally succeed in experimentally verifying it to everyone's satisfaction. But while Einstein's equation was bold, his light quantum hypothesis was revolutionary: it amounted to reviving Newton's centuries-old idea that light consists of particles.

No one tried harder than Einstein to overcome opposition to this hypothesis. Thus, in 1907 he proved the fruitfulness of the entire quantum hypothesis by showing it could at least qualitatively account for the low-temperature behavior of the specific heats of solids. Two years later he proved that Planck's radiation law of 1900 demands the coexistence of particles and waves in blackbody radiation, a proof that represents the birth of the wave-particle duality. In 1917 Einstein presented a very simple and very important derivation of Planck's radiation law (the modern laser, for example, is based on the concepts Einstein introduced here), and he also proved that light quanta must carry momentum as well as energy.

Meanwhile, Einstein had become involved in another series of researches having a direct bearing on the wave-particle duality. In mid-1924 S.N. Bose produced a very insightful derivation of Planck's radiation law - the origin of Bose-Einstein statistics - which Einstein soon developed into his famous quantum theory of an ideal gas. Shortly thereafter, he became acquainted with Louis de Broglie's revolutionary new idea that ordinary material particles, such as electrons and gas molecules, should under certain circumstances exhibit wave behavior. Einstein saw immediately that De Broglie's idea was intimately related to the Bose-Einstein statistics: both indicate that material particles can at times behave like waves. Einstein told Erwin Schrödinger of De Broglie's work, and in 1926 Schrödinger made the extraordinarily important discovery of wave mechanics. Schrödinger's (as well as C. Eckart) then proved that Schrödinger's wave mechanics and Werner Heisenberg's matrix mechanics are mathematically equivalent: they are now collectively known as quantum mechanics, one of the two most fruitful physical theories of the 20th century. Since Einstein's insights formed much of the background to both Schrödinger's and Heisenberg's discoveries, the debt quantum physicists owe to Einstein can hardly be exaggerated.

Theory of Relativity

The second of the two most fruitful physical theories of the 20th century is the theory of relativity, which to scientists and laymen alike is synonymous with the name of Einstein. Once again, there is a common misconception concerning the origin of this theory, namely, that Einstein advanced it in 1905 to "explain" the famous Michelson-Morley experiment (1887), which failed to detect a relative motion of the earth with respect to the ether, the medium through which light was assumed to propagate. In fact, it is not even certain that Einstein was aware of this experiment in 1905; nor was he familiar with H.A. Lorentz's elegant 1904 paper in which Lorentz applied the transformation equations which bear his name to electrodynamic phenomena. Rather, Einstein consciously searched for a general principle of nature that would hold the key to the explanation of a paradox that had occurred to him when he was 16: if, on the one hand, one runs at, say, 4 miles per hour alongside a train moving at 4 miles per hour, the train appears to be at rest; if, on the other hand, it were possible to run alongside a ray of light, neither experiment nor theory suggests that the ray of light - an oscillating electromagnetic wave - would appear to be at rest. Einstein eventually saw that he could postulate that no matter what the velocity of the observer, he must always observe the same velocity c for the velocity of light: roughly 186,000 miles per second. He also saw that this postulate was consistent with a second postulate: if an observer at rest and an observer moving at constant velocity carry out the same kind of experiment, they must get the same result. These are Einstein's two postulates of his special theory of relativity. Also in 1905 Einstein proved that his theory predicted that energy E and mass mare entirely interconvertible according to his famous equation, Emc².

For observational confirmation of his general theory of relativity, Einstein boldly predicted the gravitational red shift and the deflection of starlight (an amended value), as well as the quantitative explanation of U. J. J. Leverrier's long-unexplained observation that the perihelion of the planet Mercury precesses about the sun at the rate of 43 seconds of arc per century. In addition, Einstein in 1916 predicted the existence of gravitational waves, which have only recently been detected. Turning to cosmological problems the following year, Einstein found a solution to his field equations consistent with the picture (the Einstein universe) that the universe is static, approximately uniformly filled with a finite amount of matter, and finite but unbounded (in the same sense that the surface area of a smooth globe is finite but has no beginning or end).

The Man and His Philosophy

Fellow physicists were always struck with Einstein's uncanny ability to penetrate to the heart of a complex problem, to instantly see the physical significance of a complex mathematical result. Both in his scientific and in his personal life, he was utterly independent, a trait that manifested itself in his approach to scientific problems, in his unconventional dress, in his relationships with family and friends, and in his aloofness from university and governmental politics (in spite of his intense social consciousness). Einstein loved to discuss scientific problems with friends, but he was, fundamentally a "horse for single harness."

Einstein's belief in strict causality was closely related to his profound belief in the harmony of nature. That nature can be understood rationally, in mathematical terms, never ceased to evoke a deep - one might say, religious - feeling of admiration in him. "The most incomprehensible thing about the world," he once wrote, "is that it is comprehensible." How do we discover the basic laws and concepts of nature? Einstein argued that while we learn certain features of the world from experience, the free inventive capacity of the human mind is required to formulate physical theories. There is no logical link between the world of experience and the world of theory. Once a theory has been formulated, however, it must be "simple" (or, perhaps, "esthetically pleasing") and agree with experiment. One such esthetically pleasing and fully confirmed theory is the special theory of relativity. When Einstein was informed of D.C. Miller's experiments, which seemed to contradict the special theory by demanding the reinstatement of the ether, he expressed his belief in the spuriousness of Miller's results - and therefore in the harmoniousness of nature - with another of his famous aphorisms, "God is subtle, but he is not malicious."

This frequent use of God's name in Einstein's speeches and writings provides us with a feeling for his religious convictions. He once stated explicitly, "I believe in Spinoza's God who reveals himself in the harmony of all being, not in a God who concerns himself with the fate and actions of men." It is not difficult to see that this credo is consistent with his statement that the "less knowledge a scholar possesses, the farther he feels from God. But the greater his knowledge, the nearer is his approach to God." Since Einstein's God manifested Himself in the harmony of the universe, there could be no conflict between religion and science for Einstein.

To enumerate at this point the many honors that were bestowed upon Einstein during his lifetime would be to devote space to the kind of public acclamation that mattered so little to Einstein himself. How, indeed, can other human beings sufficiently honor one of their number who revolutionized their conception of the physical world, and who lived his life in the conviction that "the only life worth living is a life spent in the service of others"? When Einstein lay dying he could truly utter, as he did, "Here on earth I have done my job." It would be difficult to find a more suitable epitaph than the words Einstein himself used in characterizing his life: "God is inexorable in the way He has allotted His gifts. He gave me the stubbornness of a mule and nothing else; really, He also gave me a keen scent."

Further Reading

Numerous biographies of Einstein have been written. Three of the best are Philipp Frank, Einstein: His Life and Times, translated by George Rosen (1947); Carl Seelig, Albert Einstein: A Documentary Biography, translated by Mervyn Savill (1956); and Ronald W. Clark, Einstein: The Life and Times (1971). Einstein's illuminating "Autobiographical Notes" and bibliographies of his scientific and nonscientific writings can be found in P.A. Schilpp, ed., Albert Einstein: Philosopher-Scientist (1949; 2d ed. 1951). See also Max Born, Einstein's Theory of Relativity (trans. 1922; rev. ed. 1962); Leopold Infeld, Albert Einstein: His Work and Its Influence on Our World (1950); and Max Jammer, The Conceptual Development of Quantum Mechanics (1966).

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Albert Einstein. (credit: Courtesy of the Nobelstiftelsen, Stockholm)

(born March 14, 1879, Ulm, Württemberg, Ger. — died April 18, 1955, Princeton, N.J., U.S.) German-Swiss-U.S. scientist. Born to a Jewish family in Germany, he grew up in Munich, and in 1894 he moved to Aarau, Switz. He attended a technical school in Zürich (graduating in 1900) and during this period renounced his German citizenship; stateless for some years, he became a Swiss citizen in 1901. Einstein became a junior examiner at the Swiss patent office in 1902 and began producing original theoretical work that laid many of the foundations for 20th-century physics. He received his doctorate from the University of Zürich in 1905, the same year he won international fame with the publication of three articles: one on Brownian motion, which he explained in terms of molecular kinetic energy; one on the photoelectric effect, in which he demonstrated the particle nature of light; and one on his special theory of relativity, which included his formulation of the equivalence of mass and energy (E = mc²). Einstein held several professorships before becoming director of Berlin's Kaiser Wilhelm Institute for Physics in 1913. In 1915 he published his general theory of relativity, which was confirmed experimentally during a solar eclipse in 1919 with observations of the deviation of light passing near the Sun. He received a Nobel Prize in 1921 for his work on the photoelectric effect, his work on relativity still being controversial. He made important contributions to quantum field theory, and for decades he sought to discover the mathematical relationship between electromagnetism and gravitation, which he believed would be a first step toward discovering the common laws governing the behaviour of everything in the universe, but such a unified field theory eluded him. His theories of relativity and gravitation represented a profound advance over Newtonian physics and revolutionized scientific and philosophical inquiry. He resigned his position at the Prussian Academy when Adolf Hitler came to power and moved to Princeton, N.J., where he joined the Institute for Advanced Study. Though a longtime pacifist, he was instrumental in persuading Pres. Franklin Roosevelt in 1939 to initiate the Manhattan Project for the production of an atomic bomb, a technology his own theories greatly furthered, though he did not work on the project himself. Einstein became a U.S. citizen in 1940 but retained his Swiss citizenship. The most eminent scientist in the world in the postwar years, he declined an offer to become the first prime minister of Israel and became a strong advocate for nuclear disarmament.

For more information on Albert Einstein, visit Britannica.com.

Einstein, Albert (1879-1955) German physicist and discoverer of the theory of relativity. Born in Ulm, Einstein received his scientific education in Zurich. After an undistinguished career as a student he found employment in the Patent Office in Bern, and it was from here that in 1905 he published the papers that laid the foundation of his reputation, on the photoelectric effect, on Brownian motion, and on the special theory of relativity. In 1916 he published the general theory. In 1933 Einstein accepted the position at the Princeton Institute for Advanced Studies which he occupied for the rest of his life. Einstein maintained profound philosophical interests, and frequently emphasized the importance to his work of the philosophical thought of his predecessors, especially Hume and Mach. In his later years his reflections on the nature of the world as it is described by quantum mechanics occasioned prolonged discussion with the Danish physicist Neils Bohr. Einstein's conviction that quantum mechanics could not possibly be the last word about the nature of physical reality was frequently felt to be conservative, but the project that occupied him, the search for a field theory that would unify the four fundamental physical forces, has recently sprung back into prominence. Einstein's belief that fundamental physics should concern the ‘marble’ of space, time, and geometry, rather than the ‘wood’ of arbitrary proliferations of particles, is again congenial to many physicists.

(1879-1955), physicist. Einstein was born in Ulm, Germany, and grew up in Munich, in a family of independent-minded, nonpracticing Jews. Little is known about his childhood. Because he was slow in learning to speak--he was not fully fluent even at the age of nine--he was at various times thought to be mentally retarded. Some experts have speculated that he was dyslexic. A headmaster once told his father that what Einstein chose as a profession wouldn't matter, because "he'll never make a success at anything." At six he began learning to play the violin and became a gifted amateur violinist, maintaining this skill throughout his life.

Einstein attended the Luitpold Gymnasium in Munich, which he disliked intensely for its authoritarianism. He was deeply interested in physics and mathematics and read eagerly in both subjects. Ultimately he rebelled, leaving Luitpold at fifteen without receiving his diploma.

Without a gymnasium diploma, Einstein could not enter a German university, so he enrolled in the Swiss Federal Polytechnic School in Zurich. He was so impressed with the democratic atmosphere of Switzerland that he formally renounced his German citizenship at the age of sixteen; in 1901 he was granted Swiss citizenship, which he retained for the rest of his life.

After graduating he held several teaching jobs and became a technical assistant in the Swiss Patent Office in Berne, where he remained for six years. The job's great advantage, he later said, was that it gave him time to think about physics.

Between 1901 and 1904 Einstein published five papers on physics. In one he virtually proved the existence of molecules, solely by the use of theory; in another he showed that light is both a wave and a particle. In his sixth paper, "On the Electrodynamics of Moving Bodies," published in the summer of 1905, he established the outline of his special theory of relativity. His arguments radically revised existing concepts of electromagnetism, light, and the behavior of moving bodies as set forth in Newtonian physics. Einstein contended that the speed of light is constant, and that nothing in the universe can travel faster than light. If the velocity of light is constant, then all motion and even time itself must be relative to it. If objects could approach the speed of light, their age, mass, and size would appear very different to a stationary observer than if the objects were moving at slower speeds. A clock nearing the speed of light would slow down; if it reached the speed of light, time would stand still. Many of his contentions have been confirmed by subsequent experiments. Atomic clocks in spacecraft orbiting the earth, for example, run a fraction of a second more slowly than clocks on earth.

In the fall of 1905, Einstein published another short paper in which he proposed the famous equation, E = mc²: the energy in matter is equal to its mass multiplied by the square of the velocity of light. This equation explained how stars, like our own sun, can emit large amounts of light while losing very little mass; and it anticipated the splitting of the atom and the construction of the atom bomb thirty-five years later.

After receiving his doctorate from the University of Zurich in 1905, Einstein taught there and elsewhere until 1913, when he accepted a professorship in Berlin. There he established an Institute of Physics. He took up the question of gravity in his next major publication in 1916, "The Foundations of the General Theory of Relativity." One expert called it "the greatest feat of human thinking about nature." Whereas Newton had seen gravity as a universally present force, Einstein described it as a characteristic of matter. He proposed that gravity affected light just as it did matter and outlined both new structural laws and new laws of motion. The validation of the general theory was provided in 1919 by two English astronomical expeditions mounted to test its hypotheses by photographing an eclipse of the sun. When word was received that their results were positive, Einstein became the most famous scientist in the world overnight.

During the twenties, Einstein became more identified with his Jewish roots and worked to prevent another world war. In 1933, troubled by the swelling tide of anti-Semitism in Germany, he accepted an invitation to the Institute for Advanced Studies at Princeton, New Jersey, where he remained for the rest of his life.

Einstein's scientific work from this point was devoted to his effort to create a unified field theory, linking electromagnetism and light. Although such a theory eluded him, and other scientists proclaimed it impossible, he persisted with characteristic stubbornness. He consulted for the navy on the Manhattan Project during World War II, an action that went against his pacifist grain but seemed essential at the time because of the war's menace.

Bibliography:

Nigel Calder, Einstein's Universe (1979); Ronald W. Clark, Einstein: The Life and Times (1974).

Author:

D. Lydia Brontë

See also Manhattan Project; Science and Technology.

Life

Einstein lived as a boy in Munich and Milan, continued his studies at the cantonal school at Aarau, Switzerland, and was graduated (1900) from the Federal Institute of Technology, Zürich. Later he became a Swiss citizen. He was examiner (1902–9) at the patent office, Bern. During this period he obtained his doctorate (1905) at the Univ. of Zürich, evolved the special theory of relativity, explained the photoelectric effect, and studied the motion of atoms, on which he based his explanation of Brownian movement. In 1909 his work had already attracted attention among scientists, and he was offered an adjunct professorship at the Univ. of Zürich. He resigned that position in 1910 to become full professor at the German Univ., Prague, and in 1912 he accepted the chair of theoretical physics at the Federal Institute of Technology, Zürich.

By 1913 Einstein had won international fame and was invited by the Prussian Academy of Sciences to come to Berlin as titular professor of physics and as director of theoretical physics at the Kaiser Wilhelm Institute. He assumed these posts in 1914 and subsequently resumed his German citizenship. For his work in theoretical physics, notably on the photoelectric effect, he received the 1921 Nobel Prize in Physics. His property was confiscated (1934) by the Nazi government because he was Jewish, and he was deprived of his German citizenship. He had previously accepted (1933) a post at the Institute for Advanced Study, Princeton, which he held until his death in 1955. An ardent pacifist, Einstein was long active in the cause of world peace; however, in 1939, at the request of a group of scientists, he wrote to President Franklin Delano Roosevelt to stress the urgency of investigating the possible use of atomic energy in bombs. In 1940 he became an American citizen.

Major Contributions to Science

The Special and General Theories of Relativity

Einstein's early work on the theory of relativity (1905) dealt only with systems or observers in uniform (unaccelerated) motion with respect to one another and is referred to as the special theory of relativity; among other results, it demonstrated that two observers moving at great speed with respect to each other will disagree about measurements of length and time intervals made in each other's systems, that the speed of light is the limiting speed of all bodies having mass, and that mass and energy are equivalent. In 1911 he asserted the equivalence of gravitation and inertia, and in 1916 he completed his mathematical formulation of a general theory of relativity that included gravitation as a determiner of the curvature of a space-time continuum. He then began work on his unified field theory, which attempts to explain gravitation, electromagnetism, and subatomic phenomena in one set of laws; the successful development of such a unified theory, however, eluded Einstein.

Photons and the Quantum Theory

In addition to the theory of relativity, Einstein is also known for his contributions to the development of the quantum theory. He postulated (1905) light quanta (photons), upon which he based his explanation of the photoelectric effect, and he developed the quantum theory of specific heat. Although he was one of the leading figures in the development of quantum theory, Einstein regarded it as only a temporarily useful structure. He reserved his main efforts for his unified field theory, feeling that when it was completed the quantization of energy and charge would be found to be a consequence of it. Einstein wished his theories to have that simplicity and beauty which he thought fitting for an interpretation of the universe and which he did not find in quantum theory.

Writings

Einstein's writings include Relativity: The Special and the General Theory (1918; tr. 1920, reissued 1947) and excerpts (most of them translated) from letters, articles, and addresses collected in About Zionism (1930), The World as I See It (1934), Out of My Later Years (1950), Ideas and Opinions (1954), and Einstein on Peace (ed. by Otto Nathan and Heinz Norden, 1960). Einstein's manuscripts and correspondence are presently at the Institute for Advanced Study, Princeton. The first volume of an edition of his collected works, under the editorship of John Stachel et al., appeared in 1987.

Bibliography

See the Born-Einstein letters, ed. by M. Born (tr. 1971); biographies by R. W. Clark (1971, repr. 1991), B. Hoffmann (with H. Dukas, 1972, repr. 1989), J. Bernstein (1973, repr. 1997), A. Pais (1982), M. White and J. Gribbin (1995), D. Brian (1997), A. Folsing (1998), W. Isaacson (2007), and J. Neffe (2007); studies by P. A. Schilpp, ed. (1949, repr. 1973), M. Born (rev. ed. 1962), C. Lanczos (1965), A. J. Friedman and C. Donley (1989), D. Howard and J. Stachel (1989), A. Pais (1994), and D. Overbye (2000).

A twentieth-century physicist; Einstein was born in Germany in 1879 and moved to the United States in the 1930s. Einstein developed the special and general theories of relativity. His equation E = mc² led to the development of nuclear fission and the atomic bomb.

Quotes:

"Perfection of means and confusion of goals seem -- in my opinion -- to characterize our age."

"One must not attempt to justify them, but rather to sense their nature simply and clearly."

"In the middle of difficulty lies opportunity."

"And the high destiny of the individual is to serve rather than to rule, or to impose himself in any other way."

"It should be possible to explain the laws of physics to a barmaid."

"Education is the progressive realization of our ignorance."

See more famous quotes by Albert Einstein