History of physics

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Galileo Galilei: Often seen as the founder of physics.

The history of physics as an independent natural science began at the beginning of the 17th century with the introduction of the experimental method of scientific discovery , mainly by Galileo Galilei . He and other founders of physics often referred to traditional writings from antiquity . However, they countered these with their own observations that they had obtained in carefully planned experiments that were evaluated using mathematical methods. In addition, for the results obtained in this way, they demanded priority over purely philosophical or theologically justified statements about nature.

Classical physics developed by the end of the 19th century : First, based on the work of Isaac Newton , Classical Mechanics , which deals with the movement and interaction of bodies . Finally electrodynamics , after James Clerk Maxwell had found a theory that describes all electrical and magnetic effects in a uniform way. Gradually it was possible to trace almost all of the phenomena known at the time back to these two foundations. In particular, heat was understood in thermodynamics as the disordered movement of particles, and light in optics as an electromagnetic wave . Experimental findings, theories based on them and findings from chemistry revealed the structure of matter from atoms .

Early 20th century, it came, caused by the special and the general theory of relativity of Albert Einstein on the one hand, and the quantum physics on the other hand, to a paradigm shift . The modern physics that began at that time is based on the concepts of space, time and matter, which are fundamentally different from those of classical physics, although their proven results are retained in full. This broadened and deepened knowledge both in the microscopic ( particle , nuclear and atomic physics ) and in the astronomical ( astrophysics and cosmology ). With solid-state physics and laser physics in particular , modern physics has provided and continues to provide extremely important foundations for technical applications in a wide variety of areas of life.

Quantum physics and the theory of relativity are the cornerstones of the physical worldview today .

Prehistory of Physics

Antiquity

Greek natural philosophy took up Mesopotamian and Egyptian knowledge and looked for basic explanatory principles. Individual descriptions of the facts have already been mathematized. However, an experimental methodology was not yet established.

The Ionic materialistic natural philosophy of Thales , Anaximander , Anaximenes , Heraklit acquired knowledge of natural phenomena such as the decrease and increase in air density, the rise of warm air, magnetic attraction and amber friction.

Empedocles established the long-standing authoritative doctrine of four elements. Leucippus and Democritus introduced the atomic hypothesis , which Epicurus pursued further: everything consists of the smallest particles, which themselves are not divisible or intrinsically changeable and whose composition explains the change in phenomena.

In today's field of optics, the Greek philosophers Pythagoras , Democritus, Empedocles and others developed several theories of light. Euclid further developed it based on the ideal of geometry he had designed and, in particular, examined reflection mathematically. Ptolemy also followed this ideal mathematical method and measured u. a. the refraction of light through experiments. Heron of Alexandria tried to explain the law of reflection and the refraction of light by the fact that light takes the shortest path between two points.

The numerical ratios of melodies described in the legend of Pythagoras in the forge are the first concrete and quantitative natural law to be described , but it is not clear how this law was arrived at.

Plato assumed immaterial archetypes and tried to explain motion and gravity with them. In the Timaeus he developed approaches to a cosmology . According to Aristotle's ontology , the identity and the change of objects can be explained by the arrangement of two basic principles, form and matter. He assumed four causes, among which the cause of motion is only one (besides aim, form and matter). His movement theory is a pre-form of classical dynamics. He also described natural phenomena in a more materialistic way. Aristotle carried out various physical and other scientific studies and wrote works or lecture notes etc. a. compiled about physics, the sky, the weather, creation and decay, questions of mechanics .

With his work Physics , Aristotle coined the term “physics” (everything that has grown naturally in contrast to artefacts ); his work does not describe nature mathematically in today's sense.

In addition, there was a pronounced interest in application, which shaped inventors such as Ktesibios , Philon of Byzantium or Heron, who used hydraulic, pneumatic and mechanical phenomena. Archimedes described around 250 BC The static buoyancy and the laws of leverage . He determined the center of gravity of surfaces and bodies and mathematically based on the model of Euclid, statics and hydrostatics .

Middle Ages and Renaissance

Numerous ancient and early medieval compendia convey the physical knowledge of ancient scientists.

In the Arab cultural area are u. a. the compilations and commentaries by Avicenna and Averroes are important, which also became important for the reception of ancient knowledge in the Latin West in the 12th and 13th centuries.

Overall, Aristotle's strong interest in expanding individual physical knowledge and its summarizing systematization in the Latin West has been lost over a long period of time. Instead, an interest in nature predominates as a sign of the divine will and therefore a source of revelation , as for example in Augustine's interpretation of the Bible around the year 400.

An interest in nature in the sense of an empirical search for an explanation becomes rudimentary tangible at the beginning of the 12th century, for example in Adelard von Bath , who no longer understands nature as a “book” of divine signs, but rather biological, physiological, cosmological and climatological phenomena in his Quaestiones naturales describes and does not rely on book knowledge but on observation, experimentum, without, of course, working it out methodologically.

Following the Platonic geometrical world view, Robert Grosseteste developed a light theory which attempts to reduce quantitative, qualitative, spatial and substantial movement to laws of light ( De motu corporali et luce and De lineis ). This makes optics (with Robert scientia perspectiva ) a “model science” Roger Bacon , too, wants to explain all natural causality as the effect of energetic radiation. Witelo gives optics a similar central position in his translation and explanation of the perspectives of Ibn al-Haitham . The similarly designed Perspectiva communis Johannes Peckhams is still used by Lorenzo Ghiberti and Leonardo da Vinci .

Shortly before the middle of the 14th century, Nikolaus von Autrecourt worked out a sharp criticism of the scientific status of metaphysical claims to knowledge and the primacy of discipline. At the same time, the mercantile and technical development of the 14th century requires and enables a quantification of nature and a critique of the Aristotelian movement theory, i.e. H. generally of causation theory. Franz von Marchia and Johannes Buridan , the founders of the so-called impetus theory , which Pierre Duhem calls a “forerunner of Galileo”, are dedicated to this . This theory remains authoritative for a long time until it is replaced by the theory of inertia. Nikolaus von Oresme , Albert von Rickmersdorf and Marsilius von Inghen develop them further, only in Oxford are they met with reluctance ( Thomas Bradwardine ) or rejection ( Richard Swineshead ). The latter two belong with Johannes Dumbleton and William Heytesbury to the so-called "Oxford Calculators" at Merton College , which attempt a general mathematization of the description of nature.

Nikolaus von Oresme also takes up many of Buridan's suggestions and develops them e.g. B. with reference to the principle of thought economy to the thesis that the assumption of the earth's rotation is just as feasible as the traditional idea of ​​a rotation of the sun around the earth. He also questions the Aristotelian division of physics into a world above and below the moon, recognizes the relativity of all movement ascriptions and introduces a system of coordinates that allows quantitatively precise descriptions of qualitative changes. In the wake of these approaches, at the beginning of the 15th century z. B. Biagio Pelacani da Parma , in the middle of the 15th century for example Nikolaus von Kues , whose experiments with the scales describe quantitative methods for medicine and can be regarded as exemplary for the interests of the early Renaissance.

Probably the best-known natural scientist of the Renaissance, Leonardo da Vinci (born 1452), was mainly interested in optics, water movements, power transmission and bird flight for practical reasons as a painter and engineer and carried out precise observations of nature.

Classical physics

16th and 17th centuries

Overcoming the prevailing ideas began in modern astronomy with Nicolaus Copernicus ( De revolutionibus orbium coelestium , 1543) and the heliocentric worldview . This model found support after Johannes Kepler had evaluated the observation material from Tycho Brahe and, in particular, Galileo Galilei revolutionized observational astronomy with the telescope.

Around 1600 William Gilbert founded the theory of magnetism and electrostatics with his experiments and was the first to show that these were different phenomena. He was also the first to correctly recognize the shape of the earth's magnetic field .

In mechanics, René Descartes was one of the first to turn away from Aristotelian ideas and attempt to fathom and rationally describe the movements of bodies with the power of intellect alone. In contrast to him, however, Galileo represented a school that based its conclusions not only on logical inference, but above all on reproducible observations and experiments. Only then did physics develop from natural philosophy into a modern natural science. Galileo realized that all bodies on earth move according to the same laws that can be formulated mathematically and verified experimentally. His discoveries include the law of free fall , which contradicted the teaching of Aristotle, as well as a formulation of the law of inertia , the trajectory parabola and the pendulum law. With his conception of physics as an experimental science, Galileo had an educational effect, for example in the study of air pressure and the nature of the vacuum (from Evangelista Torricelli to Blaise Pascal to Otto von Guericke ). Robert Boyle researched the gas laws in the 17th century and Christiaan Huygens built the pendulum clocks proposed by Galileo, found the centrifugal force and used a principle of relativity when considering the elastic shock (see Galileo transformation ).

Isaac Newton

The fundamentals of classical mechanics were essentially established and formulated in 1687 by Isaac Newton in his main work Philosophiae Naturalis Principia Mathematica ( Newton's Laws ). The main goal was initially to explain Kepler's laws of celestial mechanics from a universal law of gravitation that applies to both earth and celestial bodies. An experimental confirmation in the laboratory and a determination of the gravitational constant , however, only succeeded Henry Cavendish over 100 years later. Newton already applied his laws of mechanics, for example, to the movement of other bodies and liquids.

Overall, Newton occupies a prominent position in the history of physics and in the mathematization of natural sciences. He also made important contributions to optics (reflector telescope, prism). In contrast to Christiaan Huygens ( wave optics ), he represented a corpuscular theory of light.

18th century

The infinitesimal calculus used in the formulation of mechanics, invented by Newton and independently of Gottfried Wilhelm Leibniz , was expanded, like mechanics, in particular on the European continent after the British mathematicians isolated themselves as a result of the priority dispute between Newton and Leibniz, among other things. Differential equations then formed the basis for the formulation of many natural laws.

Mathematicians and physicists such as Daniel Bernoulli , Jean-Baptiste le Rond d'Alembert , Leonhard Euler , Joseph-Louis Lagrange ( Mécanique analytique 1788, Lagrange formalism ) and Pierre-Simon Laplace (whose work was considered the pinnacle of the development of celestial mechanics) developed the Mechanics on the continent much further with the use of variation principles ( principle of the smallest effect ). France in particular dominated the field of theoretical physics at the end of the 18th century, although the driving forces were often still in theoretical astronomy (celestial mechanics) and the boundaries between theoretical physicists and mathematicians did not exist as they did in the later 20th century.

The 18th century also saw a diverse preoccupation with the phenomenon of electricity . Voltage generators (electric machines) and capacitors in the form of Leyden bottles were widely used in the physical cabinets of the Baroque. Reproducible quantitative results were obtained after the introduction of the battery by Alessandro Volta (around 1800). Towards the end of the century, Charles-Augustin de Coulomb formulated the laws of electrostatics.

In the 18th and early 19th centuries, important philosophers and intellectuals also dealt with physics. Well-known is Immanuel Kant's contribution to cosmogony and the theory of colors (1810) by Johann Wolfgang von Goethe , which the latter considered to be more important than his literary work. The natural philosophy of German idealism, especially through Friedrich Wilhelm Joseph Schelling and Georg Wilhelm Friedrich Hegel, was at times very influential in German-speaking countries and Schelling's natural philosophy influenced chemists, biologists and in physics, for example, Hans Christian Ørsted and Johann Wilhelm Ritter . It resulted in speculative physics (the title of a journal of the Schelling Circle in Jena), which was fiercely opposed in Germany at the beginning of the 19th century by physicists such as Johann Christian Poggendorff , the editor of the Annalen der Physik . In the 1840s, this also meant that the early, from today's point of view, pioneering works on energy conservation by Robert Mayer and Hermann von Helmholtz could not appear there because the works in question seemed too speculative to Poggendorff, they came from medical professionals and besides - especially something Mayer concerned - were unclear and influenced by natural philosophical thinking. Here the endeavors to professionalise and delimit physics as a discipline in the first half of the 19th century also become clear. Natural Philosophy was the term for theoretical physics in England for a long time, as is shown by the names of the associated chairs.

19th century

The 19th century is characterized in particular by the development of the laws of thermodynamics and the development of the field concept in the field of electrodynamics , culminating in Maxwell's equations .

The basics of thermodynamics were laid by Sadi Carnot in 1824, who considered cycle processes with idealized heat engines. The energy concept and the concept of energy conservation were also worked out, among other things in the work of Julius Robert von Mayer , the experiments of James Prescott Joule (experimental measurement of the heat equivalent of work), by Rudolf Clausius , from whom the term entropy and 2. Main law of thermodynamics originate from Lord Kelvin and Hermann von Helmholtz . A microscopic interpretation of thermodynamics as a statistical theory of ensembles that obey the laws of classical mechanics was experienced by thermodynamics in statistical mechanics , which was founded in particular by James Clerk Maxwell , Josiah Willard Gibbs and Ludwig Boltzmann . Max Planck and Albert Einstein , who essentially founded modern physics at the beginning of the 20th century, were still trained as specialists in thermodynamics and statistical mechanics and initially made a name for themselves in these fields.

From considerations on heat conduction, Joseph Fourier obtained the Fourier analysis method, which is fundamental for theoretical physics. Advances in continuum mechanics were made in the formulation of the Navier-Stokes equations as an extension of the Euler equations for ideal liquids and in the investigations of turbulence by Osborne Reynolds . The 19th century also brought significant advances in the field of technical mechanics, elasticity theory and acoustics (wave phenomena such as the Doppler effect according to Christian Doppler ).

James Clerk Maxwell

The foundations of electrodynamics were laid by Hans Christian Ørsted (connection between electricity (current) and magnetism), André-Marie Ampère and Michael Faraday (electromagnetic induction, field concepts). In summary and in a unified theory of close-range effects, the electrodynamics was described by James Clerk Maxwell. He also provided an electromagnetic theory of light (the wave nature of light had already established itself at the beginning of the century with Thomas Young and Augustin Jean Fresnel ). Subsequently, Oliver Heaviside and Heinrich Hertz , who were the first to detect electromagnetic waves, played a major role in the elaboration . Maxwell assumed - like most other physicists of his time - that the electromagnetic waves propagate in a medium that fills the entire space, the ether . However, all attempts to prove this ether experimentally, especially the Michelson-Morley experiment , failed, which is why the ether hypothesis had to be dropped later.

Maxwell was one of the preeminent exponents of theoretical physics who came from Great Britain in the 19th century and made the country a leader in physics in the 19th century. They also included William Rowan Hamilton , who later found a new formulation of mechanics and geometrical optics that was later influential in quantum mechanics ( Hamiltonian mechanics ), Lord Kelvin and Lord Rayleigh (Theory of Sound). In Germany, Hermann von Helmholtz in Berlin was the dominant personality in physics with contributions in a wide variety of areas.

Overall, towards the end of the 19th century, the idea spread that physics was more or less complete, that there was nothing new to discover. In retrospect, however, there were already some clear indications that this was not the case: In chemistry, certain principles gave an idea of ​​the atomic structure of matter (although there were also influential opponents of atomism at the end of the 19th century). In the spectral analysis ( Joseph von Fraunhofer , Gustav Robert Kirchhoff , Robert Bunsen ) certain regularities of the spectra were discovered (see Rydberg formula ) that could not be explained. The ability of the spectra to be influenced by magnetic fields in the Zeeman effect was a first indication of electrons in atoms. The discoveries of the electron in cathode rays ( JJ Thomson ), X-rays ( Röntgen ), the photo effect ( Hallwax ), radioactivity ( Becquerel ) etc. raised further questions that were unanswered at the time. In particular, the question of the sun's energy source and the black body theory remained unanswered.

The theory of relativity was also hidden in the structure of Maxwell's equations, as suggested by studies of the electrodynamics of moving bodies by Hendrik Antoon Lorentz and Henri Poincaré and which Albert Einstein recognized in full in the following century.

Modern physics

The 20th century began with the formulation of the two central theories of modern physics: the quantum theory by Max Planck (1900) and the relativity theory by Albert Einstein . Both theories led to a fundamental reshaping of physics.

On the experimental side, the discovery of radioactivity at the end of the 19th century ( Henri Becquerel ) and its research by Marie Curie at the beginning of the 20th century were of decisive importance, followed by the discovery of the atomic nucleus by Ernest Rutherford ( Rutherford scattering experiment ). The electron in cathode rays was the first elementary particle to be discovered in the 19th century ( JJ Thomson ). An important advance was the investigation of previously unknown parts of the electromagnetic spectrum with the discovery of X-rays by Wilhelm Conrad Röntgen , with great effects on medicine and the microscopic examination of solids ( Max von Laue , William Henry Bragg , William Lawrence Bragg ).

theory of relativity

Albert Einstein

The special theory of relativity (SRT) was founded by Albert Einstein after preliminary work by Hendrik Antoon Lorentz and Henri Poincaré . He was the first to see its full implications. Due to the postulated equality of all observers in inertial systems ( principle of relativity ) and the invariance of the speed of light, it was necessary to redefine space and time. After the SRT, both sizes were no longer absolute, but rather dependent on the choice of the reference system. The Lorentz transformation took the place of the Galileo transformation .

The general theory of relativity (ART), also founded by Einstein, extended the knowledge of the SRT to non- inertial systems . Accordingly, gravitational effects and inertial forces are completely equivalent to each other . This resulted in the equality of heavy and inert mass as well as the curvature of spacetime . The Euclidean geometry of space, which was still tacitly regarded as correct in classical physics , now proved to be no longer viable. Soon after the First World War, ART found confirmation in observations (light deflection at the edge of the sun during a solar eclipse, Arthur Eddington ) and the cosmological models formulated therein ( Friedmann , Georges Lemaître ) in the discovery of the expansion of the universe ( Edwin Hubble ).

Quantum theory

Quantum theory has its roots in the quantum theory , with which it Max Planck succeeded, the spectrum of the thermal radiation of a black body by Planck's law to explain: Planck assumed that the matter radiation is not continuous but in small "portions" - quantum - absorbed and emitted. Albert Einstein concluded from this that light ( photon ) was a particle and thus explained the photo effect , which was discovered by Wilhelm Hallwachs in the 19th century . The particle character of light was in stark contradiction to the wave theory of light, which had so far proven itself excellently. Louis de Broglie later went one step further and postulated that this wave-particle dualism is not just a property of light, but a basic principle of nature. That is why he ascribed a wave character to matter. Niels Bohr , Arnold Sommerfeld and others developed the semi-classical Bohr model of the atom with quantized energies, which gave a first plausible explanation for the line spectra of atoms. The older quantum theory soon proved to be inadequate, especially in explaining complex spectra. Around 1925 Werner Heisenberg , Max Born (from whom the statistical interpretation of the wave function originates), Pascual Jordan and Wolfgang Pauli developed the matrix mechanics. Here the quantization phenomena were explained by the non-interchangeability of the operators assigned to the basic measured quantities such as momentum and position. Heisenberg also recognized that these variables are not exactly determined at the same time and estimated this in his uncertainty relation . Erwin Schrödinger independently formulated the basis of wave mechanics with the Schrödinger equation . This equation is a partial differential equation and an eigenvalue equation: The eigenvalues ​​of the Hamilton operator are the energies of the possible states. Matrix and wave mechanics turned out to be two aspects of the same theory: Quantum mechanics proper . By the end of the 1920s, the formulation had been finalized by Paul Dirac in particular , and the new theory achieved great success by applying it not only to atomic physics, but also to molecules, solids and other areas. The spin , a fundamental property of all particles that can not be understood in classical physics, was discovered in 1925 ( George Uhlenbeck , Samuel Goudsmit ). The fundamental difference between bosons (integer spin, Bose-Einstein statistics ) on the one hand and fermions (half- integer spin, Fermi-Dirac statistics ) on the other has been recognized (see the spin statistics theorem by Wolfgang Pauli). With the Klein-Gordon equation and the Dirac equation , relativistic formulations of quantum theory arrive. The prediction of antiparticles developed from this was confirmed by Carl D. Anderson .

The foundations of quantum theory were established in key experiments such as the Franck-Hertz experiment (quantized inelastic collision of electrons with atoms), the Millikan experiment (quantization of the charge), the Compton effect (scattering of photons on free charge carriers), the star Gerlach experiment (directional quantization of angular momentum) and confirmed in the Davisson-Germer experiment (diffraction of matter waves).

Even more than the special and general theory of relativity, quantum physics represented a paradigm shift in physics. Classical physics was strictly deterministic in principle . This means that the same initial conditions under identical circumstances always lead to the same test results. This determinism did not exist in quantum physics. Max Born introduced the statistical interpretation of the wave functions, expanded in the Copenhagen interpretation of quantum theory by Bohr and Heisenberg in 1928. Einstein vehemently rejected this interpretation, but remained isolated.

1930s, applications of quantum theory

The 1930s were marked by the expansion of nuclear physics, which received an upswing with the development of the first particle accelerator (in particular the cyclotron by Ernest O. Lawrence ). The neutron was added as a further fundamental elementary particle building block in addition to the electron and proton ( James Chadwick ) and soon afterwards further elementary particles, which were initially investigated primarily by natural accelerators in the form of cosmic cosmic radiation , with the essential new discoveries only after the Second World War from the second half of the 1940s ( PMS Blackett et al.). The neutron was fundamental to understanding nuclei and its decay led to the discovery of the fourth fundamental interaction (besides gravitation, electromagnetic and the strong interaction that holds the nuclei together), the weak interaction. The first core models were developed, such as B. the droplet model by Carl Friedrich von Weizsäcker . To date, however, there is no self-contained, satisfactory theory of the atomic nucleus. At the end of the 1930s, nuclear fission was discovered by Otto Hahn and interpreted theoretically by Lise Meitner . After World War II broke out, the United States launched the Manhattan Project to develop atomic bombs . Numerous well-known physicists were involved in the project, which was under the scientific direction of J. Robert Oppenheimer . The first controlled chain reaction succeeded Enrico Fermi in 1942 and formed the basis for the peaceful use of nuclear energy. In addition, this, along with radar research during World War II, marked the beginning of big science and massive funding of science and technology by government agencies in the US and other countries and through the formation of a military-industrial complex .

After the seizure of power by the Nazis in 1933, Germany lost its leading position in physics, which had held the 20th century in the first third. Numerous physicists left Germany and later Austria because they were persecuted because of their Jewish descent or their political commitment, including such well-known scientists as Einstein, Schrödinger, Meitner and others. In the so-called “ German Physics ” (represented by, for example, Philipp Lenard , Johannes Stark and others), important findings from modern physics were rejected for ideological reasons. As expected, the "German Physics" turned out to be a scientific dead end. During the Second World War, Germany also undertook military-motivated research into nuclear fission as part of the uranium project , but by the end of the war it was still a long way from building an atomic bomb. Research in Germany in this and other militarily relevant areas was prohibited after the war until 1956. She also suffered in Germany from the destruction of the war and the expulsion of numerous scientists under the National Socialists and had to struggle to gain a foothold again after the war.

In the 1930s the quantum theory of fields was also developed (Dirac, Jordan et al.), With the basic picture of interactions mediated by the exchange of particles ( Hideki Yukawa , Fermi).

Upswing in physics after the Second World War

The USA took on the leading role in physics after the Second World War. At the end of the 1940s, Richard Feynman (who also founded the path integral formulation of quantum mechanics after an idea by Dirac ), Julian Schwinger , Freeman Dyson and other consistent formulations of quantum theories of fields ( quantum field theory , quantum electrodynamics ). Radar research during World War II resulted in many new experimental processes, in particular the development of the measles (mid-1950s) and from it that of the laser (around 1960), which not only revolutionized spectroscopy, and methods such as nuclear magnetic resonance spectroscopy . The solid-state physics gave another pillar of technological development in the form of semiconductors and transistors ( John Bardeen , William B. Shockley ). Macroscopic quantum phenomena, such as those of superconductors (John Bardeen et al.) And superfluids , which had long been misunderstood, found an explanation with the methods of quantum field theory applied here to many-particle physics. Solid-state physics repeatedly made surprising discoveries (such as high-temperature superconductors and the quantum Hall effect in the 1980s), not only with great technological implications, but also with theoretical approaches that also fertilized elementary particle physics and other areas of physics. Of particular importance here was the development of the theory of phase transitions and critical phenomena ( Lew Landau , Kenneth Wilson ). Wilson worked out the influential concept of the renormalization group, which is used, for example, in the theory of phase transitions and in elementary particle physics and quantum field theory.

Development of the standard model

The development of particle accelerators after the war led to the discovery of an entire elementary particle zoo, which theorists brought order, especially from the 1960s onwards. Symmetries and their quantum field theoretical formulation proved to be of particular importance as gauge theories . Gauge theories were originally introduced by Hermann Weyl as extensions of the general theory of relativity and, in particular in the form of Yang-Mills theories, proved to be fundamental for the standard model of elementary particles and fundamental interactions that was now emerging. Of great importance was the discovery of the violation of a fundamental symmetry in the weak interaction, the parity violation (1956, postulated by Yang , Lee and confirmed in the Wu experiment ). Murray Gell-Mann made significant contributions to the strong interaction, especially through the introduction of point-like constituents ( quarks ), from which mesons and baryons are built and which were observed in high-energy experiments in the late 1960s. From the 1970s, a special Yang Mills theory, quantum chromodynamics, emerged as a theory of strong interaction and a building block of the Standard Model, followed by a union of electrical and weak interaction ( Steven Weinberg , Abdus Salam , Sheldon Glashow , 1960s) . The development of the large accelerators, which are exemplary for Big Science , in which thousands of scientists are nothing unusual about the experiments, confirmed this model bit by bit, right up to the discovery of the last quark (top quark) in the 1990s and the Higgs boson Early 2010s.

Theoretical elementary particle physics was dominated in the years after the completion of the Standard Model (late 1970s) by string theory , which tries to explain the phenomenology of the Standard Model by considering extended (thread-like) instead of point-like elementary particles and the solution of another great unsolved problem in physics , the union of gravitation and quantum theory. However, the theory suffers from the large gap between the Planck scale of the description of the theory and experimentally accessible dimensions. The theory, on the other hand, was very fruitful for a new mutual exchange of mathematics and physics.

Further developments

The development of computers and electronics made possible by the miniaturization of electronic circuits not only made the development of the particle accelerator experiments that confirmed the Standard Model possible, but also revolutionized theoretical physics. One of the new branches made possible by computer development, in particular, is chaos theory , which in the 1970s led to a paradigm shift in areas such as classical mechanics, which until then were largely considered complete. With the computer, completely new questions and improvements in the forecasting options of many models opened up. The miniaturization of circuits was later pushed into the quantum realm and new research fields such as mesoscopic physics and quantum information theory emerged .

On a large scale in cosmology and astrophysics ( quasars and active galaxies, neutron stars and pulsars , black holes ), great progress was made in the second half of the 20th century, both theoretically and in the field of observations (astronomy in the most varied of wavelengths). Black holes changed from an exotic possibility to an established explanatory model and cosmology became a quantitative science , especially with the discovery of 3-K background radiation . There were also diverse connections from physics in the very small (elementary particles) to astrophysics and cosmology ( astroparticle physics ), for example in the explanation of the problem of solar neutrinos . The inflationary model became one of the building blocks of the modern explanation of nature, with new fundamental unsolved problems emerging in the late 20th century in the form of the discovery of dark matter and the accelerated expansion of the universe .

See also

literature

Bibliographies

  • Roderick W. Home: The history of classical physics . A selected, annotated bibliography. Garland, New York 1984, ISBN 0-8240-9067-5 .
  • Stephen G. Brush, Lanfranco Belloni: The history of modern physics . An international bibliography. Garland, New York 1983, ISBN 0-8240-9117-5 .

Overview diagrams and manuals

Lexicons

Special topics

mechanics
  • René Dugas : A history of mechanics. Routledge and Kegan, 1955
  • Istvan Szabo : History of Mechanical Principles. Birkhäuser, 1987
  • Eduard Jan Dijksterhuis The mechanization of the worldview. Springer, Berlin / Heidelberg / New York 1956. (Reprint 1983)
  • Ernst Mach : The development of mechanics. Brockhaus, 1897.
  • Various books by Max Jammer such as The concept of force
Thermodynamics, Kinetic Gas Theory
  • Stephen G. Brush : The Kind of Motion We Call Heat - A History of the Kinetic Theory of Gases in the 19th Century . 2 volumes. North Holland 1976.
Electrodynamics
  • Edmund T. Whittaker : History of the theories of ether and electricity. 2 volumes, Dover 1989. (first 1910)
  • Olivier Darrigol : Electrodynamics from Ampère to Einstein. Oxford University Press, 2003
  • John Heilbron : Electricity in the 17th and 18th Century: Study of Early Modern Physics. University of California Press, 1979. (Dover 1999)
Quantum theory
Quantum field theory, elementary particle physics
  • Abraham Pais : Inward Bound. Of Matter and Forces in the Physical World . Clarendon Press, Oxford, 1986.
  • Silvan S. Schweber : QED and the Men Who Made It: Dyson, Feynman, Schwinger, and Tomonaga. Princeton University Press, Princeton 1994.
middle Ages
  • AC Crombie : Augustine to Galileo : The History of Science AD ​​400 - 1650. Penguin 1969, ISBN 0-14-055074-7 .
  • S. Donati, Andreas Speer: Physics and natural philosophy. In: Lexicon of the Middle Ages. Volume 6, JB Metzler, 2000, pp. 2111-2117.
  • Edward Grant : Physical Science in the Middle Ages. Wiley History of Science Series, John Wiley, New York / London 1971.
  • Edward Grant: The Foundations of Modern Science in the Middle Ages. Their Religious, Institutional and Intellectual Contexts. Cambridge University Press, Cambridge 1996, ISBN 0-521-56762-9 .
  • Edward Grant (Ed.): A Sourcebook in Medieval Science . Harvard University Press, Cambridge 1974, ISBN 0-674-82360-5 .
  • Toby E. Huff: The Rise of Early Modern Science. Islam, China, and the West. Cambridge University Press, 2003, ISBN 0-521-52994-8 .
  • David C. Lindberg : The Beginnings of Western Science . University of Chicago Press, Chicago 1992, ISBN 0-226-48230-8 .
  • David C. Lindberg (Ed.): Science in the Middle Ages . University of Chicago Press, Chicago 1976, ISBN 0-226-48233-2 .
  • MH Shank (Ed.): The Scientific Enterprise in Antiquity and the Middle Ages . University of Chicago Press, 2000, ISBN 0-226-74951-7 .
  • J. Thijssen: The position of the scholastic natural philosophy in the history of physics. Medieval autumn or modern spring? In: Jan A. Aertsen, Martin Pickavé (Ed.): Autumn of the Middle Ages? Questions about evaluating the 14th and 15th centuries. De Gruyter, 2004, p. 512ff.
Older representations

Ernst Gerland , Edmund Hoppe , Johann Christian Poggendorff , August Heller , Ferdinand Rosenberger , Emil Wilde (optics), Carl Ramsauer (experiments)

Individual evidence

  1. ↑ a b Schreier 1990, 451
  2. ↑ Eugene Hecht: Optics . 4th edition. Oldenbourg, Munich / Vienna 2005, ISBN 3-486-27359-0 , p. 1 .
  3. ↑ Károly Simonyi: cultural history of physics. Chapter "Mysticism and Mathematics: Pythagoras". Harri Deutsch publishing house, Thun / Frankfurt am Main 1990, pp. 61-66.
  4. ↑ Cf. De Genesi ad litteram , De civitate Dei 21, 8; Donati / spear.
  5. ↑ Donati / Speer with reference to Quaest. nat. 6 and 22
  6. ↑ Donati / Speer
  7. ^ Opus maius, part 4, based on Donati / Speer
  8. ↑ Donati / Speer
  9. ↑ Donati / Speer
  10. ^ Enrico Giannetto: The impetus theory: Between history of physics and science education. In: Science & Education. 2/3 (1993), pp. 227-238. doi : 10.1007 / BF00490064 .
  11. ↑ Here after Flasch, The philosophical thinking in the Middle Ages, Stuttgart: Reclam 2000, 543
  12. ↑ Donati / Speer
  13. ↑ Cf. Flasch, 545
  14. ↑ Cf. Flasch, 569-572
  15. ↑ Barry Gower, Speculation in Physics: the history and practice of Naturphilosophie , Stud. Hist. Phil. Sci., 3, 1973, 301
  16. ↑ Walther Gerlach , in Propylaen Weltgeschichte (19th century), and Walther Gerlach, On the 150th birthday of Julius Robert Mayer, Physikalische Blätter 1964, p. 407, doi: 10.1002 / phbl.19640200903 (free full text)
  17. ↑ Thomas S. Kuhn identified natural philosophy as one of the factors that led to the principle of energy conservation in a classic article in 1959. Thomas S. Kuhn, Energy conservation as an example of simultaneous discovery, in Marshall Clagett et al. a., Critical problems in the history of science, University of Wisconsin Press, 1959, pp. 321-356, reprinted in Kuhn: The essential tension, University of Chicago Press, 1977, pp. 66-104. According to Kuhn, two further trigger factors were the preoccupation with machines and conversion processes.
  18. ↑ The widespread use of chaotic behavior in classical physics only became clear in chaos theory from the 1970s and here, too, led to a paradigm shift.

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