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Fundamental Ideas and Problems

of the Theory of Relativity

"for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect"

Albert Einstein

Germany and Switzerland
Kaiser-Wilhelm-Institut (now Max-Planck-Institut) für Physik Berlin, Germany
b. 1879 (in Ulm, Germany) d. 1955

Biography

Albert Einstein was born at Ulm, in Württemberg, Germany, on March 14, 1879. Six weeks later the family moved to Munich, where he later on began his schooling at the Luitpold Gymnasium. Later, they moved to Italy and Albert continued his education at Aarau, Switzerland and in 1896 he entered the Swiss Federal Polytechnic School in Zurich to be trained as a teacher in physics and mathematics. In 1901, the year he gained his diploma, he acquired Swiss citizenship and, as he was unable to find a teaching post, he accepted a position as technical assistant in the Swiss Patent Office. In 1905 he obtained his doctor's degree.

During his stay at the Patent Office, and in his spare time, he produced much of his remarkable work and in 1908 he was appointed Privatdozent in Berne. In 1909 he became Professor Extraordinary at Zurich, in 1911 Professor of Theoretical Physics at Prague, returning to Zurich in the following year to fill a similar post. In 1914 he was appointed Director of the Kaiser Wilhelm Physical Institute and Professor in the University of Berlin. He became a German citizen in 1914 and remained in Berlin until 1933 when he renounced his citizenship for political reasons and emigrated to America to take the position of Professor of Theoretical Physics at Princeton*. He became a United States citizen in 1940 and retired from his post in 1945.

After World War II, Einstein was a leading figure in the World Government Movement, he was offered the Presidency of the State of Israel, which he declined, and he collaborated with Dr. Chaim Weizmann in establishing the Hebrew University of Jerusalem.

Einstein always appeared to have a clear view of the problems of physics and the determination to solve them. He had a strategy of his own and was able to visualize the main stages on the way to his goal. He regarded his major achievements as mere stepping-stones for the next advance.

At the start of his scientific work, Einstein realized the inadequacies of Newtonian mechanics and his special theory of relativity stemmed from an attempt to reconcile the laws of mechanics with the laws of the electromagnetic field. He dealt with classical problems of statistical mechanics and problems in which they were merged with quantum theory: this led to an explanation of the Brownian movement of molecules. He investigated the thermal properties of light with a low radiation density and his observations laid the foundation of the photon theory of light.

In his early days in Berlin, Einstein postulated that the correct interpretation of the special theory of relativity must also furnish a theory of gravitation and in 1916 he published his paper on the general theory of relativity. During this time he also contributed to the problems of the theory of radiation and statistical mechanics.

In the 1920's, Einstein embarked on the construction of unified field theories, although he continued to work on the probabilistic interpretation of quantum theory, and he persevered with this work in America. He contributed to statistical mechanics by his development of the quantum theory of a monatomic gas and he has also accomplished valuable work in connection with atomic transition probabilities and relativistic cosmology.

After his retirement he continued to work towards the unification of the basic concepts of physics, taking the opposite approach, geometrisation, to the majority of physicists.

Einstein's researches are, of course, well chronicled and his more important works include Special Theory of Relativity (1905), Relativity (English translations, 1920 and 1950), General Theory of Relativity (1916), Investigations on Theory of Brownian Movement (1926), and The Evolution of Physics (1938). Among his non-scientific works, About Zionism (1930), Why War? (1933), My Philosophy (1934), and Out of My Later Years (1950) are perhaps the most important.

Albert Einstein received honorary doctorate degrees in science, medicine and philosophy from many European and American universities. During the 1920's he lectured in Europe, America and the Far East and he was awarded Fellowships or Memberships of all the leading scientific academies throughout the world. He gained numerous awards in recognition of his work, including the Copley Medal of the Royal Society of London in 1925, and the Franklin Medal of the Franklin Institute in 1935.

Einstein's gifts inevitably resulted in his dwelling much in intellectual solitude and, for relaxation, music played an important part in his life. He married Mileva Maric in 1903 and they had a daughter and two sons; their marriage was dissolved in 1919 and in the same year he married his cousin, Elsa Löwenthal, who died in 1936. He died on April 18, 1955 at Princeton, New Jersey.

Nobel Lecture: Albert Einstein

Fundamental Ideas and Problems of the Theory of Relativity

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Documentary

At a dinner at the Savoy Hotel, London, England, on 27 October 1930, the author George Bernard Shaw paid tribute to Professor Albert Einstein in an after-dinner speech.*

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Banquet Speech

As the Laureate was unable to be present at the Nobel Banquet at Grand Hôtel, Stockholm, December 10, 1922, the speech was read by the German Minister M. Nadolny (in German).

Da Professor Einstein durch seine Reise nach dem fernen Osten verhindert ist, die hohen Ehren des Nobelpreises selbst entgegenzunehmen, ist mir die Aufgabe und die Ehre zugefallen, seinen Preis aus den Händen S. M. des Königs zu empfangen und mich euch in seinem Namen für die schönen Worte zu bedanken, die Herr Professor Arrhenius bei der Preisverteilung und Herr Professor Söderbaum in seiner eben verklungenen Rede auf die Herren Preisträger seiner Arbeit und seiner Person gewidmet haben.

Mein Verhältnis zur Wissenschaft war immer nur das des Empfangenden, nie des Leistenden. Es wäre daher vermessen, wenn ich hier zu den erlauchten Führern der schwedischen Wissenschaft auch nur ein Wort im Sinne des Wissenschaftlers Einstein sprechen wollte. Aber ich möchte doch annehmen und glaube es zum Ausdruck bringen zu können, dass auch Albert Einstein sich rein menschlich freuen wird, seine Arbeit in so ehrenvoller Weise anerkannt zu sehen. Und weiter möchte ich der Freude meines Volkes Ausdruck geben darüber, dass wieder einmal einer von den Seinen etwas für die ganze Menschheit hat leisten können, und schliesslich der Hoffnung, das man auch in der Schweiz, die dem Gelehrten lange Jahre Heimat und Arbeitsmöglichkeit geboten hat, an dieser Freude Anteil nimmt.

Eine Parallele zwischen dem, was uns heute Abend beschäftigt, und dem, was meiner Komptenz unterliegt, darf ich aber vielleicht doch ziehen. - Nicht die, dass in der Politik die Relativität meindestens ebenso gilt wie im Weltraum. - Aber die, dass die Nobelstiftung, indem sie das Streben nach dem höchsten Ziele der Menschheit, nach der kulturellen Völkergemeinschaft, anfeuert und belohnt, auch ein international-politisches Organ ist, und dass Alfred Nobel, indem er die wissenschaftliche Leistung auf ein so hohes, über den Völkern stehendes Piedestal hob und zugleich sein Land zum Hort seiner Ideen machte, die Völker im kulturellen Wetteifer zusammenzuführen, Diplomatendienst im besten Sinne leistete, da er höchsten Dienst am Vaterlande mit edelstem Dienst der Menschheit vereinigte.

Der Nobelpreisträger Einstein ist bekanntlich nicht nur Gelehrter und Forscher, sondern auch ein begeisterter Priester der Völkerversöhnung. Es wird also geviss in seinem Sinne sein, wenn ich meine Worte mit dem Wunsche schliesse, dass die edlen und schönen Ziele Alfred Nobel's, deren berufene Hüter die schwedischen Akademien sind, unentwegt und vielleicht in Zukunft noch schneller als bisher ihrer Verwirklichung entgegengehen möchten. Und so leere ich mein Glas auf die Königliche Wissenschaftsakademie.

Presentation Speech

Presentation Speech by Professor S. Arrhenius, Chairman of the Nobel Committee for Physics of the Royal Swedish Academy of Sciences, on December 10, 1922*

Your Majesty, Your Royal Highnesses, Ladies and Gentlemen.

There is probably no physicist living today whose name has become so widely known as that of Albert Einstein. Most discussion centres on his theory of relativity. This pertains essentially to epistemology and has therefore been the subject of lively debate in philosophical circles. It will be no secret that the famous philosopher Bergson in Paris has challenged this theory, while other philosophers have acclaimed it wholeheartedly. The theory in question also has astrophysical implications which are being rigorously examined at the present time.

Throughout the first decade of this century the so-called Brownian movement stimulated the keenest interest. In 1905 Einstein founded a kinetic theory to account for this movement by means of which he derived the chief properties of suspensions, i.e. liquids with solid particles suspended in them. This theory, based on classical mechanics, helps to explain the behaviour of what are known as colloidal solutions, a behaviour which has been studied by Svedberg, Perrin, Zsigmondy and countless other scientists within the context of what has grown into a large branch of science, colloid chemistry.

A third group of studies, for which in particular Einstein has received the Nobel Prize, falls within the domain of the quantum theory founded by Planck in 1900. This theory asserts that radiant energy consists of individual particles, termed "quanta", approximately in the same way as matter is made up of particles, i.e. atoms. This remarkable theory, for which Planck received the Nobel Prize for Physics in 1918, suffered from a variety of drawbacks and about the middle of the first decade of this century it reached a kind of impasse. Then Einstein came forward with his work on specific heat and the photoelectric effect. This latter had been discovered by the famous physicist Hertz in 1887. He found that an electrical spark passing between two spheres does so more readily if its path is illuminated with the light from another electrical discharge. A more exhaustive study of this interesting phenomenon was carried out by Hallwachs who showed that under certain conditions a negatively charged body, e.g. a metal plate, illuminated with light of a particular colour - ultraviolet has the strongest effect - loses its negative charge and ultimately assumes a positive charge. In 1899 Lenard demonstrated the cause to be the emission of electrons at a certain velocity from the negatively charged body. The most extraordinary aspect of this effect was that the electron emission velocity is independent of the intensity of the illuminating light, which is proportional only to the number of electrons, whereas the velocity increases with the frequency of the light. Lenard stressed that this phenomenon was not in good agreement with the then prevailing concepts.

An associated phenomenon is photo-luminescence, i.e.phosphorescence and fluorescence. When light impinges on a substance the latter will occasionally become luminous as a result of phosphorescence or fluorescence. Since the energy of the light quantum increases with the frequency, it will be obvious that a light quantum with a certain frequency can only give rise to the formation of a light quantum of lower or, at most, equal frequency. Otherwise energy would be created. The phosphorescent or fluorescent light hence has a lower frequency than the light inducing the photo-luminescence. This is Stokes' rule which was explained in this way by Einstein by means of the quantum theory.

Similarly, when a quantum of light falls on a metal plate it can at most yield the whole of its energy to an electron there. A part of this energy is consumed in carrying the electron out into the air, the remainder stays with the electron as kinetic energy. This applies to an electron in the surface layer of the metal. From this can be calculated the positive potential to which the metal can be charged by irradiation. Only if the quantum contains sufficient energy for the electron to perform the work of detaching itself from the metal does the electron move out into the air. Consequently, only light having a frequency greater than a certain limit is capable of inducing a photo-electric effect, however high the intensity of the irradiating light. If this limit is exceeded the effect is proportional to the light intensity at constant frequency. Similar behaviour occurs in the ionisation of gas molecules and the so-called ionisation potential may be calculated, provided that the frequency of the light capable of ionising the gas is known.

Einstein's law of the photo-electrical effect has been extremely rigorously tested by the American Millikan and his pupils and passed the test brilliantly. Owing to these studies by Einstein the quantum theory has been perfected to a high degree and an extensive literature grew up in this field whereby the extraordinary value of this theory was proved. Einstein's law has become the basis of quantitative photo-chemistry in the same way as Faraday's law is the basis of electro-chemistry.**

Frequently Asked Questions

Question: When was Albert Einstein born?

Answer: Albert Einstein was born on 14 March 1879.

Question: Where was he born?

Answer: He was born in Ulm, Germany.

Question: When did he die?

Answer: He died 18 April 1955 in Princeton, New Jersey, USA.

Question: Who were his parents?

Answer: His father was Hermann Einstein and his mother was Pauline Einstein (born Koch).

Question: Did he have any sisters and brothers?

Answer: He had one sister named Maja.

Question: Did he marry and have children?

Answer: He was married to Mileva Marić between 1903 and 1919. They had three children, Lieserl (born 1902), Hans Albert (born 1904) and Eduard (born 1910). He married Elsa Löwenthal in 1919 and they lived together until her death in 1936.

Question: Where did he receive his education?

Answer: He received his main education at the following schools:
Catholic elementary school in Munich, Germany (1885-1888)
Luitpold Gymnasium in Munich, Germany (1888-1894)
Cantonal school in Aarau, Switzerland (1895-1896)
Swiss Federal Institute of Technology in Zurich, Switzerland (1896-1900)
Ph.D. from Zurich University, Switzerland (1905)

Question: When was Albert Einstein awarded the Nobel Prize in Physics?

Answer: The Nobel Prize Awarding Institution, the Royal Swedish Academy of Sciences, decided to reserve the Nobel Prize in Physics in 1921, and therefore no Physics Prize was awarded that year. According to the statutes, a reserved prize can be awarded the year after, and Albert Einstein was awarded the 1921 Nobel Prize in Physics in 1922.

Question: Did Albert Einstein attend the Nobel Prize Award Ceremony?

Answer: The Nobel Prize was announced on 9 November 1922. Being too remote from Sweden, Albert Einstein could not attend the Nobel Prize Award Ceremony in Stockholm on 10 December the same year.

Question: For what did he receive the Nobel Prize?

Answer: Einstein was rewarded for his many contributions to theoretical physics, and especially for his discovery of the law of the photoelectric effect.

Question: What is the photoelectric effect?

Answer: The photoelectric effect is a phenomenon in which electrons are emitted from the surface of matter (usually metals) when light shines upon it. Einstein explained the effect by proposing that light consists of small particles, or quanta, called photons, which carry energy that is proportional to the frequency of light. The electrons in the matter that absorb the energy of the photon get ejected. These findings were published in 1905 in the paper "On a Heuristic Viewpoint Concerning the Production and Transformation of Light". Einstein's observations that the photoelectric effect could only be explained if light behaves like a particle, not a wave, was instrumental in establishing the hypothesis that light can behave both like a wave and a particle.

Question: What are the practical applications of the photoelectric effect?

Answer: The photoelectric effect is very important for our daily life. It is the basis for photosynthesis, which is like a very effective solar cell where sunlight is absorbed by plants to make them grow. The effect also forms the basis for a variety of devices such as photodiodes, which are used in light detection within fibre optics, telecommunications networks, solar cells, imaging and many other applications.

Question: When did he deliver his Nobel Lecture?

Answer: He gave his Nobel Lecture on 11 July 1923 in Gothenburg, Sweden.

Question: What other scientific accomplishments is Albert Einstein known for?

Answer: Albert Einstein is one of the most influential physicists in the 20^th century. In 1905 Einstein published four landmark papers in physics - on the photoelectric effect, Brownian motion, the special theory of relativity and equivalence of matter and energy (E=mc²). The year 2005 was named the "World Year of Physics" in recognition of the 100th anniversary of Einstein's publications. Einstein is also well known for his general relativity theory published 1915 that complements his special relativity theory of 1905.