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116-832: The Grand Accélérateur National d'Ions Lourds ( GANIL ), or Large Heavy Ion National Accelerator , is a French national nuclear physics research center in Caen . The facility has been in operation since 1983 and consists primarily of two serialised synchrocyclotrons . It is a part of the French Alternative Energies and Atomic Energy Commission (CEA), more specifically the CEA Paris-Saclay center. Projects: Similar facilities: 49°12′52″N 0°21′38″W  /  49.21444°N 0.36056°W  / 49.21444; -0.36056 Nuclear physics Nuclear physics should not be confused with atomic physics , which studies

232-600: A Hanukkah celebration. Einstein next traveled to California, where he met Caltech 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 . 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 and film star Charlie Chaplin , both noted for their pacifism. Carl Laemmle , head of Universal Studios , gave Einstein

348-526: A classical system , rather than a quantum-mechanical one. In the resulting liquid-drop model , the nucleus has an energy that arises partly from surface tension and partly from electrical repulsion of the protons. The liquid-drop model is able to reproduce many features of nuclei, including the general trend of binding energy with respect to mass number, as well as the phenomenon of nuclear fission . Superimposed on this classical picture, however, are quantum-mechanical effects, which can be described using

464-493: A phase transition from normal nuclear matter to a new state, the quark–gluon plasma , in which the quarks mingle with one another, rather than being segregated in triplets as they are in neutrons and protons. Eighty elements have at least one stable isotope which is never observed to decay, amounting to a total of about 251 stable nuclides. However, thousands of isotopes have been characterized as unstable. These "radioisotopes" decay over time scales ranging from fractions of

580-512: 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

696-459: 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 before his thirteenth birthday. A family tutor, Max Talmud , said that only a short time after he had given the twelve year old Einstein a geometry textbook, the boy "had worked through

812-471: A company that manufactured electrical equipment based on direct current . He often related a formative event from his youth, when he was sick in bed and his father brought him a compass . This sparked his lifelong fascination with electromagnetism . He realized that "Something deeply hidden had to be behind things." Albert attended St. Peter's Catholic elementary school in Munich from the age of five. When he

928-408: A different number of protons. In alpha decay , which typically occurs in the heaviest nuclei, the radioactive element decays by emitting a helium nucleus (2 protons and 2 neutrons), giving another element, plus helium-4 . In many cases this process continues through several steps of this kind, including other types of decays (usually beta decay) until a stable element is formed. In gamma decay ,

1044-655: A diploma handed to him by King Alfonso XIII . (His Spanish trip also gave him a chance to meet a fellow Nobel laureate, the neuroanatomist Santiago Ramón y Cajal .) 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 of the League of Nations , a group set up by the League to encourage scientists, artists, scholars, teachers and other people engaged in

1160-501: 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

1276-526: A few months later to Pavia , where they settled in Palazzo Cornazzani . Einstein, then fifteen, stayed behind in Munich in order to finish his schooling. His father wanted him to study electrical engineering , 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

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1392-463: 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

1508-408: A nucleus decays from an excited state into a lower energy state, by emitting a gamma ray . The element is not changed to another element in the process (no nuclear transmutation is involved). Other more exotic decays are possible (see the first main article). For example, in internal conversion decay, the energy from an excited nucleus may eject one of the inner orbital electrons from the atom, in

1624-404: A paper which laid the foundations for the concepts of both laser and maser , and contained a trove of information that would be beneficial to developments in physics later on. A joint paper in 1935, with Nathan Rosen , introduced the notion of a wormhole . In the middle part of his career, Einstein made important contributions to statistical mechanics and quantum theory. Especially notable

1740-646: A platform from which to promote traditional Catholic doctrine. Einstein's former physics professor Hendrik Lorentz and the Polish chemist Marie Curie were also members of the committee. 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

1856-518: A process which produces high speed electrons but is not beta decay and (unlike beta decay) does not transmute one element to another. In nuclear fusion , two low-mass nuclei come into very close contact with each other so that the strong force fuses them. It requires a large amount of energy for the strong or nuclear forces to overcome the electrical repulsion between the nuclei in order to fuse them; therefore nuclear fusion can only take place at very high temperatures or high pressures. When nuclei fuse,

1972-515: 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

2088-635: 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's Prime Minister, İsmet İnönü , 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

2204-488: A second to trillions of years. Plotted on a chart as a function of atomic and neutron numbers, the binding energy of the nuclides forms what is known as the valley of stability . Stable nuclides lie along the bottom of this energy valley, while increasingly unstable nuclides lie up the valley walls, that is, have weaker binding energy. The most stable nuclei fall within certain ranges or balances of composition of neutrons and protons: too few or too many neutrons (in relation to

2320-507: A spin of ± + 1 ⁄ 2 . In the Rutherford model of nitrogen-14, 20 of the total 21 nuclear particles should have paired up to cancel each other's spin, and the final odd particle should have left the nucleus with a net spin of 1 ⁄ 2 . Rasetti discovered, however, that nitrogen-14 had a spin of 1. In 1932 Chadwick realized that radiation that had been observed by Walther Bothe , Herbert Becker , Irène and Frédéric Joliot-Curie

2436-444: A subsequent letter to physicist and friend Max Born , 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

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2552-596: 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 was to premiere a few days later in Hollywood, and Chaplin invited Einstein and Elsa to join him as his special guests. Walter Isaacson , Einstein's biographer, described this as "one of

2668-494: A very large amount of energy is released and the combined nucleus assumes a lower energy level. The binding energy per nucleon increases with mass number up to nickel -62. Stars like the Sun are powered by the fusion of four protons into a helium nucleus, two positrons , and two neutrinos . The uncontrolled fusion of hydrogen into helium is known as thermonuclear runaway. A frontier in current research at various institutions, for example

2784-503: 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 ). After his first public lecture in Tokyo, he met Emperor Yoshihito and his wife at

2900-474: 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. Correspondence between Einstein and Marić, discovered and published in 1987, revealed that in early 1902, while Marić was visiting her parents in Novi Sad , she gave birth to a daughter, Lieserl . When Marić returned to Switzerland it

3016-412: Is held together by the strong nuclear force, unless it is too large. Unstable nuclei may undergo alpha decay, in which they emit an energetic helium nucleus, or beta decay, in which they eject an electron (or positron ). After one of these decays the resultant nucleus may be left in an excited state, and in this case it decays to its ground state by emitting high-energy photons (gamma decay). The study of

3132-459: Is the source of energy for nuclear power plants and fission-type nuclear bombs, such as those detonated in Hiroshima and Nagasaki , Japan, at the end of World War II . Heavy nuclei such as uranium and thorium may also undergo spontaneous fission , but they are much more likely to undergo decay by alpha decay. For a neutron-initiated chain reaction to occur, there must be a critical mass of

3248-479: The ETH Zurich , to take up a chair in theoretical physics. His teaching activities there centred on thermodynamics and analytical mechanics, and his research interests included the molecular theory of heat, continuum mechanics 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

3364-623: The First World War in July 1914 marked the beginning of Einstein's gradual estrangement from the nation of his birth. When the " Manifesto of the Ninety-Three " 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

3480-703: The German Empire , Einstein moved to Switzerland in 1895, and at the age of seventeen he enrolled in the mathematics and physics teaching diploma program at the Swiss federal polytechnic school . In 1903, he secured a permanent position at the Swiss Patent Office . In 1905, he submitted a successful PhD dissertation to the University of Zurich . In 1914, he moved to Berlin to join the Prussian Academy of Sciences and

3596-687: The Humboldt University of Berlin , becoming director of the Kaiser Wilhelm Institute for Physics in 1917. In 1933, while Einstein was visiting the United States, Adolf Hitler came to power in Germany. Horrified by the Nazi persecution of his fellow Jews, Einstein decided to remain in the US. On the eve of World War II , he endorsed a letter to President Franklin D. Roosevelt alerting him to

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3712-620: 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: "[the] intellectual 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

3828-466: The Joint European Torus (JET) and ITER , is the development of an economically viable method of using energy from a controlled fusion reaction. Nuclear fusion is the origin of the energy (including in the form of light and other electromagnetic radiation) produced by the core of all stars including our own Sun. Nuclear fission is the reverse process to fusion. For nuclei heavier than nickel-62

3944-403: The atom as a whole, including its electrons . Discoveries in nuclear physics have led to applications in many fields. This includes nuclear power , nuclear weapons , nuclear medicine and magnetic resonance imaging , industrial and agricultural isotopes, ion implantation in materials engineering , and radiocarbon dating in geology and archaeology . Such applications are studied in

4060-433: The nuclear shell model , developed in large part by Maria Goeppert Mayer and J. Hans D. Jensen . Nuclei with certain " magic " numbers of neutrons and protons are particularly stable, because their shells are filled. Other more complicated models for the nucleus have also been proposed, such as the interacting boson model , in which pairs of neutrons and protons interact as bosons . Ab initio methods try to solve

4176-462: The "heavier elements" (carbon, element number 6, and elements of greater atomic number ) that we see today, were created inside stars during a series of fusion stages, such as the proton–proton chain , the CNO cycle and the triple-alpha process . Progressively heavier elements are created during the evolution of a star. Energy is only released in fusion processes involving smaller atoms than iron because

4292-474: 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

4408-633: 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 in Democracy in America (1835). He wrote of his transatlantic hosts in highly approving terms: "What strikes

4524-616: The Century . Albert Einstein was born in Ulm , in the Kingdom of Württemberg in the German Empire, on 14 March 1879. His parents, secular Ashkenazi Jews , were Hermann Einstein , a salesman and engineer, and Pauline Koch . In 1880, the family moved to Munich 's borough of Ludwigsvorstadt-Isarvorstadt , where Einstein's father and his uncle Jakob founded Elektrotechnische Fabrik J. Einstein & Cie,

4640-602: The Europeans " 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 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

4756-472: 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

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4872-637: 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 camp. 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 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

4988-743: The Nobel award, the Royal Society 's Copley Medal , was not hung around Einstein's neck until 1925. He was elected an International Member of the American Philosophical Society 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

5104-549: 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 derived the Planck spectrum in 1924. That same year, Einstein was elected an International Honorary Member of the American Academy of Arts and Sciences . Britain's closest equivalent of

5220-832: The Parish of Roughton, Norfolk . 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 at his home, and later, Austen Chamberlain and former Prime Minister Lloyd George . Einstein asked them to help bring Jewish scientists out of Germany. British historian Martin Gilbert notes that Churchill responded immediately, and sent his friend, physicist Frederick Lindemann , to Germany to seek out Jewish scientists and place them in British universities. Churchill later observed that as

5336-519: 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 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 , printed a banner headline that read: "Revolution in Science ;– New Theory of

5452-546: 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 's father that he secured a post in Bern 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

5568-651: 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 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

5684-532: 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

5800-528: The Universe ;– Newtonian Ideas Overthrown". 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

5916-783: 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 in Prague, a move which required him to become an Austrian citizen of the Austro-Hungarian Empire . His time in Prague saw him producing eleven research papers. In July 1912, he returned to his alma mater ,

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6032-574: The advice of the polytechnic's principal, he completed his secondary education at the Argovian cantonal school (a gymnasium ) in Aarau , Switzerland, graduating in 1896. While lodging in Aarau with the family of Jost Winteler , 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

6148-403: The atom, in which the atom had a very small, very dense nucleus containing most of its mass, and consisting of heavy positively charged particles with embedded electrons in order to balance out the charge (since the neutron was unknown). As an example, in this model (which is not the modern one) nitrogen-14 consisted of a nucleus with 14 protons and 7 electrons (21 total particles) and the nucleus

6264-453: The beta decay spectrum was continuous rather than discrete. That is, electrons were ejected from the atom with a continuous range of energies, rather than the discrete amounts of energy that were observed in gamma and alpha decays. This was a problem for nuclear physics at the time, because it seemed to indicate that energy was not conserved in these decays. The 1903 Nobel Prize in Physics

6380-538: The binding energy per nucleon peaks around iron (56 nucleons). Since the creation of heavier nuclei by fusion requires energy, nature resorts to the process of neutron capture. Neutrons (due to their lack of charge) are readily absorbed by a nucleus. The heavy elements are created by either a slow neutron capture process (the so-called s -process ) or the rapid , or r -process . The s process occurs in thermally pulsing stars (called AGB, or asymptotic giant branch stars) and takes hundreds to thousands of years to reach

6496-486: The binding energy per nucleon decreases with the mass number. It is therefore possible for energy to be released if a heavy nucleus breaks apart into two lighter ones. The process of alpha decay is in essence a special type of spontaneous nuclear fission . It is a highly asymmetrical fission because the four particles which make up the alpha particle are especially tightly bound to each other, making production of this nucleus in fission particularly likely. From several of

6612-600: The care of his mother or in temporary confinement in an asylum. After her death, he was committed permanently to Burghölzli , the Psychiatric University Hospital in Zürich. 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 ;

6728-542: 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 , newly entrusted to British rule by the League of Nations in the aftermath of the First World War. Sir Herbert Samuel ,

6844-542: The content of Proca's equations for developing a theory of the atomic nuclei in Nuclear Physics. In 1935 Hideki Yukawa proposed the first significant theory of the strong force to explain how the nucleus holds together. In the Yukawa interaction a virtual particle , later called a meson , mediated a force between all nucleons, including protons and neutrons. This force explained why nuclei did not disintegrate under

6960-474: The discovery of radioactivity by Henri Becquerel in 1896, made while investigating phosphorescence in uranium salts. The discovery of the electron by J. J. Thomson a year later was an indication that the atom had internal structure. At the beginning of the 20th century the accepted model of the atom was J. J. Thomson's "plum pudding" model in which the atom was a positively charged ball with smaller negatively charged electrons embedded inside it. In

7076-714: 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 a Magnetic Field". Einstein excelled at physics and mathematics from an early age, and soon acquired the mathematical expertise normally only found in

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7192-426: The equivalence of mass and energy to within 1% as of 1934. Alexandru Proca was the first to develop and report the massive vector boson field equations and a theory of the mesonic field of nuclear forces . Proca's equations were known to Wolfgang Pauli who mentioned the equations in his Nobel address, and they were also known to Yukawa, Wentzel, Taketani, Sakata, Kemmer, Heitler, and Fröhlich who appreciated

7308-469: 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 (a slow drift in the point in Mercury's elliptical orbit at which it approaches the Sun most closely). A total eclipse of

7424-422: 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 by the gravitational pull of the Sun as it passed close to the Sun's photosphere (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 . By

7540-418: The field of nuclear engineering . Particle physics evolved out of nuclear physics and the two fields are typically taught in close association. Nuclear astrophysics , the application of nuclear physics to astrophysics , is crucial in explaining the inner workings of stars and the origin of the chemical elements . The history of nuclear physics as a discipline distinct from atomic physics , starts with

7656-412: The foil with their trajectories being at most slightly bent. But Rutherford instructed his team to look for something that shocked him to observe: a few particles were scattered through large angles, even completely backwards in some cases. He likened it to firing a bullet at tissue paper and having it bounce off. The discovery, with Rutherford's analysis of the data in 1911, led to the Rutherford model of

7772-468: 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 , Mileva Marić . Over the next few years, the pair spent many hours discussing their shared interests and learning about topics in physics that

7888-547: The heat emanating from the Earth's core results from radioactive decay. However, it is not known if any of this results from fission chain reactions. According to the theory, as the Universe cooled after the Big Bang it eventually became possible for common subatomic particles as we know them (neutrons, protons and electrons) to exist. The most common particles created in the Big Bang which are still easily observable to us today were protons and electrons (in equal numbers). The protons would eventually form hydrogen atoms. Almost all

8004-669: The heaviest elements of lead and bismuth. The r -process is thought to occur in supernova explosions , which provide the necessary conditions of high temperature, high neutron flux and ejected matter. These stellar conditions make the successive neutron captures very fast, involving very neutron-rich species which then beta-decay to heavier elements, especially at the so-called waiting points that correspond to more stable nuclides with closed neutron shells (magic numbers). Albert Einstein Albert Einstein ( / ˈ aɪ n s t aɪ n / , EYEN -styne ; German: [ˈalbɛʁt ˈʔaɪnʃtaɪn] ; 14 March 1879 – 18 April 1955)

8120-439: The heaviest nuclei whose fission produces free neutrons, and which also easily absorb neutrons to initiate fission, a self-igniting type of neutron-initiated fission can be obtained, in a chain reaction . Chain reactions were known in chemistry before physics, and in fact many familiar processes like fires and chemical explosions are chemical chain reactions. The fission or "nuclear" chain-reaction , using fission-produced neutrons,

8236-417: The influence of proton repulsion, and it also gave an explanation of why the attractive strong force had a more limited range than the electromagnetic repulsion between protons. Later, the discovery of the pi meson showed it to have the properties of Yukawa's particle. With Yukawa's papers, the modern model of the atom was complete. The center of the atom contains a tight ball of neutrons and protons, which

8352-481: 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 and Giuseppe Motta . By persuading Secretary General Eric Drummond to deny Einstein the place on the committee reserved for a Swiss thinker, they created an opening for Gonzague de Reynold , who used his League of Nations position as

8468-635: 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 , 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

8584-449: 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". In February 1933, while on a visit to the United States, Einstein knew he could not return to Germany with

8700-469: The neutrons created in the Big Bang were absorbed into helium-4 in the first three minutes after the Big Bang, and this helium accounts for most of the helium in the universe today (see Big Bang nucleosynthesis ). Some relatively small quantities of elements beyond helium (lithium, beryllium, and perhaps some boron) were created in the Big Bang, as the protons and neutrons collided with each other, but all of

8816-660: The nuclear many-body problem from the ground up, starting from the nucleons and their interactions. Much of current research in nuclear physics relates to the study of nuclei under extreme conditions such as high spin and excitation energy. Nuclei may also have extreme shapes (similar to that of Rugby balls or even pears ) or extreme neutron-to-proton ratios. Experimenters can create such nuclei using artificially induced fusion or nucleon transfer reactions, employing ion beams from an accelerator . Beams with even higher energies can be used to create nuclei at very high temperatures, and there are signs that these experiments have produced

8932-409: The number of protons) will cause it to decay. For example, in beta decay , a nitrogen -16 atom (7 protons, 9 neutrons) is converted to an oxygen -16 atom (8 protons, 8 neutrons) within a few seconds of being created. In this decay a neutron in the nitrogen nucleus is converted by the weak interaction into a proton, an electron and an antineutrino . The element is transmuted to another element, with

9048-424: 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

9164-428: 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

9280-454: The potential German nuclear weapons program and recommended that the US begin similar research , though he generally viewed the idea of nuclear weapons with great dismay. 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, and demonstrated that if

9396-450: The president of Columbia University , who described Einstein as "the ruling monarch of the mind". Harry Emerson Fosdick , pastor at New York's Riverside Church , 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 during

9512-574: The problem of the spin of nitrogen-14, as the one unpaired proton and one unpaired neutron in this model each contributed a spin of 1 ⁄ 2 in the same direction, giving a final total spin of 1. With the discovery of the neutron, scientists could at last calculate what fraction of binding energy each nucleus had, by comparing the nuclear mass with that of the protons and neutrons which composed it. Differences between nuclear masses were calculated in this way. When nuclear reactions were measured, these were found to agree with Einstein's calculation of

9628-409: The quantum theory of radiation, and the development of Bose–Einstein statistics . 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 , which asserts that an observer in an infinitesimally small box falling freely in a gravitational field would be unable to find any evidence that

9744-498: The relevant isotope present in a certain space under certain conditions. The conditions for the smallest critical mass require the conservation of the emitted neutrons and also their slowing or moderation so that there is a greater cross-section or probability of them initiating another fission. In two regions of Oklo , Gabon, Africa, natural nuclear fission reactors were active over 1.5 billion years ago. Measurements of natural neutrino emission have demonstrated that around half of

9860-546: The rise to power of the Nazis under Germany's new chancellor, Adolf Hitler . 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 repeatedly raided his family's apartment in Berlin. He and his wife Elsa returned to Europe in March, and during

9976-482: 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 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

10092-469: The source of the energy of radioactivity would have to wait for the discovery that the nucleus itself was composed of smaller constituents, the nucleons . In 1906, Ernest Rutherford published "Retardation of the α Particle from Radium in passing through matter." Hans Geiger expanded on this work in a communication to the Royal Society with experiments he and Rutherford had done, passing alpha particles through air, aluminum foil and gold leaf. More work

10208-408: 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 . 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 as a whole. In 1917, Einstein wrote

10324-486: The strong and weak nuclear forces (the latter explained by Enrico Fermi via Fermi's interaction in 1934) led physicists to collide nuclei and electrons at ever higher energies. This research became the science of particle physics , the crown jewel of which is the standard model of particle physics , which describes the strong, weak, and electromagnetic forces . A heavy nucleus can contain hundreds of nucleons . This means that with some approximation it can be treated as

10440-608: The support of several Argentine scholars, including Julio Rey Pastor , Jakob Laub , and Leopoldo Lugones . and was financed primarily by the Council of the University of Buenos Aires and the Asociación Hebraica Argentina (Argentine Hebraic Association) with a smaller contribution from the Argentine-Germanic Cultural Institution. In December 1930, Einstein began another significant sojourn in

10556-544: 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 (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

10672-543: The time with him that they requested. After arriving in New York City, Einstein was taken to various places and events, including Chinatown , a lunch with the editors of The New York Times , and a performance of Carmen at the Metropolitan Opera , 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 ,

10788-909: 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 , Ernst Mach and David Hume , all of whom significantly influenced Einstein's own subsequent ideas and beliefs. Einstein's first paper, "Folgerungen aus den Capillaritätserscheinungen" ("Conclusions drawn from

10904-570: The trip, they learned that the German Reichstag had passed the Enabling Act 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 , Belgium on 28 March, Einstein immediately went to

11020-635: 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 and differential calculus " 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

11136-470: 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 , founded in April 1933 by British Liberal politician William Beveridge to help academics escape Nazi persecution, Einstein

11252-415: The world, objecting that "God does not play dice". Second, he attempted to devise a unified field theory by generalizing his geometric theory of gravitation to include electromagnetism . As a result, he became increasingly isolated from the mainstream modern physics . His intellectual achievements and originality made Einstein broadly synonymous with genius . In 1999, he was named Time 's Person of

11368-420: The year being celebrated as an annus mirabilis for physics akin to 1666 (the year in which Isaac Newton experienced his greatest epiphanies). The publications deeply impressed Einstein's contemporaries. Einstein's sabbatical as a civil servant approached its end in 1908, when he secured a junior teaching position at the University of Bern . In 1909, a lecture on relativistic electrodynamics that he gave at

11484-443: The years that followed, radioactivity was extensively investigated, notably by Marie Curie , a Polish physicist whose maiden name was Sklodowska, Pierre Curie , Ernest Rutherford and others. By the turn of the century, physicists had also discovered three types of radiation emanating from atoms, which they named alpha , beta , and gamma radiation. Experiments by Otto Hahn in 1911 and by James Chadwick in 1914 discovered that

11600-434: Was a German-born theoretical physicist who is widely held as one of the most influential scientists . Best known for developing the theory of relativity , Einstein also made important contributions to quantum mechanics . His mass–energy equivalence formula E = mc , which arises from special relativity , has been called "the world's most famous equation". He received the 1921 Nobel Prize in Physics . Born in

11716-418: Was a particularly remarkable development since at that time fusion and thermonuclear energy, and even that stars are largely composed of hydrogen (see metallicity ), had not yet been discovered. The Rutherford model worked quite well until studies of nuclear spin were carried out by Franco Rasetti at the California Institute of Technology in 1929. By 1925 it was known that protons and electrons each had

11832-516: 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 Cromer home in a secluded wooden cabin on Roughton Heath in

11948-439: Was actually due to a neutral particle of about the same mass as the proton, that he called the neutron (following a suggestion from Rutherford about the need for such a particle). In the same year Dmitri Ivanenko suggested that there were no electrons in the nucleus — only protons and neutrons — and that neutrons were spin 1 ⁄ 2 particles, which explained the mass not due to protons. The neutron spin immediately solved

12064-584: Was awarded jointly to Becquerel, for his discovery and to Marie and Pierre Curie for their subsequent research into radioactivity. Rutherford was awarded the Nobel Prize in Chemistry in 1908 for his "investigations into the disintegration of the elements and the chemistry of radioactive substances". In 1905, Albert Einstein formulated the idea of mass–energy equivalence . While the work on radioactivity by Becquerel and Marie Curie predates this, an explanation of

12180-515: Was briefly in a relationship with Margarita Konenkova, thought by some to be a Russian spy; her husband, the Russian sculptor Sergei Konenkov , created the bronze bust of Einstein at the Institute for Advanced Study at Princeton. Following an episode of acute mental illness at about the age of twenty, Einstein's son Eduard was diagnosed with schizophrenia . He spent the remainder of his life either in

12296-401: Was completed on 30 April 1905 and approved by Professor Alfred Kleiner 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 and the equivalence of mass and energy —have led to

12412-641: Was eight, he was transferred to the Luitpold Gymnasium , 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 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 and

12528-540: Was elected a Foreign Member of the Royal Netherlands Academy of Arts and Sciences in 1920, and a Foreign Member of the Royal Society in 1921 . In 1922, he was awarded the 1921 Nobel Prize in Physics "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 skeptically, and

12644-438: Was greater than his own. In the spring of 1913, two German visitors, Max Planck and Walther Nernst , 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 and a chair at the Humboldt University of Berlin that would allow him to pursue his research supported by

12760-502: Was his work on the quantum physics of radiation , in which light consists of particles, subsequently called photons . With the Indian physicist Satyendra Nath Bose , 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

12876-408: Was performed during 1909, at the University of Manchester . Ernest Rutherford's assistant, Professor Johannes "Hans" Geiger, and an undergraduate, Marsden, performed an experiment in which Geiger and Marsden under Rutherford's supervision fired alpha particles ( helium 4 nuclei ) at a thin film of gold foil. The plum pudding model had predicted that the alpha particles should come out of

12992-407: Was published in 1909 by Geiger and Ernest Marsden , and further greatly expanded work was published in 1910 by Geiger . In 1911–1912 Rutherford went before the Royal Society to explain the experiments and propound the new theory of the atomic nucleus as we now understand it. Published in 1909, with the eventual classical analysis by Rutherford published May 1911, the key preemptive experiment

13108-495: Was surrounded by 7 more orbiting electrons. Around 1920, Arthur Eddington anticipated the discovery and mechanism of nuclear fusion processes in stars , in his paper The Internal Constitution of the Stars . At that time, the source of stellar energy was a complete mystery; Eddington correctly speculated that the source was fusion of hydrogen into helium, liberating enormous energy according to Einstein's equation E = mc . This

13224-476: Was unable to go to Stockholm 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

13340-597: 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 and Princeton , and in Washington, he visited the White House with representatives of the National Academy of Sciences . He returned to Europe via London, where he was the guest of the philosopher and statesman Viscount Haldane . He used his time in

13456-469: 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 in infancy. Einstein and Marić married in January 1903. In May 1904, their son Hans Albert was born in Bern , Switzerland. Their son Eduard was born in Zürich in July 1910. In letters that Einstein wrote to Marie Winteler in

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