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History of science and technology

The history of science and technology (HST) is a field of history that examines the understanding of the natural world (science) and the ability to manipulate it (technology) at different points in time. This academic discipline also studies the cultural, economic, and political impacts of and contexts for scientific practices.

Academic study of history of science
History of science is an academic discipline with an international community of specialists. Main professional organizations for this field include the History of Science Society, the British Society for the History of Science, and the European Society for the History of Science.

Much of the study of the history of science has been devoted to answering questions about what science is, how it functions, and whether it exhibits large-scale patterns and trends.

History of the academic study of history of science
Histories of science were originally written by practicing and retired scientists, starting primarily with William Whewell's History of the Inductive Sciences (1837), as a way to communicate the virtues of science to the public.

Auguste Comte proposed that there should be a specific discipline to deal with the history of science.

The development of the distinct academic discipline of the history of science and technology did not occur until the early 20th century. Historians have suggested that this was bound to the changing role of science during the same time period.

After World War I, extensive resources were put into teaching and researching the discipline, with the hopes that it would help the public better understand both Science and Technology as they came to play an exceedingly prominent role in the world.

In the decades since the end of World War II, history of science became an academic discipline, with graduate schools, research institutes, public and private patronage, peer-reviewed journals, and professional societies.

Formation of academic departments
In the United States, a more formal study of the history of science as an independent discipline was initiated by George Sarton's publications, Introduction to the History of Science (1927) and the journal Isis (founded in 1912). Sarton exemplified the early 20th-century view of the history of science as the history of great men and great ideas. He shared with many of his contemporaries a Whiggish belief in history as a record of the advances and delays in the march of progress.

The study of the history of science continued to be a small effort until the rise of Big Science after World War II. With the work of I. Bernard Cohen at Harvard, the history of science began to become an established subdiscipline of history in the United States.

In the United States, the influential bureaucrat Vannevar Bush, and the president of Harvard, James Conant, both encouraged the study of the history of science as a way of improving general knowledge about how science worked, and why it was essential to maintain a large scientific workforce.

Argentina

 * Buenos Aires Institute of Technology, Argentina, has been offering courses on History of the Technology and the Science.
 * National Technological University, Argentina, has a complete history program on its offered careers.

Australia

 * The University of Sydney offers both undergraduate and postgraduate programmes in the History and Philosophy of Science, run by the Unit for the History and Philosophy of Science, within the Science Faculty. Undergraduate coursework can be completed as part of either a Bachelor of Science or a Bachelor of Arts Degree. Undergraduate study can be furthered by completing an additional Honours year. For postgraduate study, the Unit offers both coursework and research-based degrees. The two course-work based postgraduate degrees are the Graduate Certificate in Science (HPS) and the Graduate Diploma in Science (HPS). The two research based postgraduate degrees are a Master of Science (MSc) and Doctor of Philosophy (PhD).

Belgium

 * University of Liège, has a Department called Centre d'histoire des Sciences et Techniques.

Canada

 * Carleton University Ottawa offer courses in Ancient Science and Technology in its Technology, Society and Environment program.
 * University of Toronto has a program in History and Philosophy of Science and Technology.
 * Huron University College offers a course in the History of Science which follows the development and philosophy of science from 10,000 BCE to the modern day.
 * University of King's College in Halifax, Nova Scotia has a History of Science and Technology Program.

France

 * Nantes University has a dedicated Department called Centre François Viète.
 * Paris Diderot University (Paris 7) has a Department of History and Philosophy of Science.
 * A CNRS research center in History and Philosophy of Science SPHERE, affiliated with Paris Diderot University, has a dedicated history of technology section.
 * Pantheon-Sorbonne University (Paris 1) has a dedicated Institute of History and Philosophy of Science and Technics.
 * The École Normale Supérieure de Paris has a history of science department.

Germany

 * Technische Universität Berlin, has a program in the History of Science and Technology.

Greece

 * The University of Athens has a Department of Philosophy and History of Science

India
History of science and technology is a well-developed field in India. At least three generations of scholars can be identified. The first generation includes D.D.Kosambi, Dharmpal, Debiprasad Chattopadhyay and Rahman. The second generation mainly consists of Ashis Nandy, Deepak Kumar, Dhruv Raina, S. Irfan Habib, Shiv Visvanathan, Gyan Prakash, Stan Lourdswamy, V.V. Krishna, Itty Abraham, Richard Grove, Kavita Philip, Mira Nanda and Rob Anderson. There is an emergent third generation that includes scholars like Abha Sur and Jahnavi Phalkey.

Departments and Programmes

The National Institute of Science, Technology and Development Studies had a research group active in the 1990s which consolidated social history of science as a field of research in India. Currently there are several institutes and university departments offering HST programmes.
 * Jawaharlal Nehru University has an Mphil-PhD program that offer specialisation in Social History of Science. It is at the History of Science and Education group of the Zakir Husain Centre for Educational Studies (ZHCES) in the School of Social Sciences. Renowned Indian science historians Deepak Kumar and Dhruv Raina teach here. Also, *Centre for Studies in Science Policy has an Mphil-PhD program that offers specialization in Science, Technology, and Society along with various allied subdisciplines.
 * Central University of Gujarat has an MPhil-PhD programme in Studies in Science, Technology & Innovation Policy at the Centre for Studies in Science, Technology & Innovation Policy (CSSTIP), where Social History of Science and Technology in India is a major emphasis for research and teaching.
 * Banaras Hindu University has programs: one in History of Science and Technology at the Faculty of Science and one in Historical and Comparative Studies of the Sciences and the Humanities at the Faculty of Humanities.
 * Andhra University has now set History of Science and Technology as a compulsory subject for all the First year B-Tech students.

Israel

 * Tel Aviv University. The Cohn Institute for the History and Philosophy of Science and Ideas is a research and graduate teaching institute within the framework of the School of History of Tel Aviv University.
 * Bar-Ilan University has a graduate program in Science, Technology, and Society.

Japan

 * Kyoto University has a program in the Philosophy and History of Science.
 * Tokyo Institute of Technology has a program in the History, Philosophy, and Social Studies of Science and Technology.
 * The University of Tokyo has a program in the History and Philosophy of Science.

Netherlands

 * Utrecht University, has two co-operating programs: one in History and Philosophy of Science at the Faculty of Natural Sciences and one in Historical and Comparative Studies of the Sciences and the Humanities at the Faculty of Humanities.

Poland

 * Institute for the History of Science of the Polish Academy of Sciences offers PhD programmes and habilitation degrees in the fields of History of Science, Technology and Ideas.

Spain

 * University of the Basque Country, offers a master's degree and PhD programme in History and Philosophy of Science and runs since 1952 THEORIA. International Journal for Theory, History and Foundations of Science. The university also sponsors the Basque Museum of the History of Medicine and Science, the only open museum of History of Science of Spain, that in the past offered also PhD courses.
 * Universitat Autònoma de Barcelona, offers a master's degree and PhD programme in HST together with the Universitat de Barcelona.
 * Universitat de València, offers a master's degree and PhD programme in HST together with the Consejo Superior de Investigaciones Científicas.

Sweden

 * Linköpings universitet, has a Science, Technology, and Society program which includes HST.

Switzerland

 * University of Bern, has an undergraduate and a graduate program in the History and Philosophy of Science.

 Ukraine

 * State University of Infrastructure and Technologies, has a Department of Philosophy and History of Science and technology.

United Kingdom

 * University of Bristol has a masters and PhD program in the Philosophy and History of Science.
 * University of Cambridge has an undergraduate course and a large masters and PhD program in the History and Philosophy of Science (including the History of Medicine).
 * University of Durham has several undergraduate History of Science modules in the Philosophy department, as well as Masters and PhD programs in the discipline.
 * University of Kent has a Centre for the History of the Sciences, which offers Masters programmes and undergraduate modules.
 * University College London's Department of Science and Technology Studies offers undergraduate programme in History and Philosophy of Science, including two BSc single honour degrees (UCAS V550 and UCAS L391), plus both major and minor streams in history, philosophy and social studies of science in UCL's Natural Sciences programme. The department also offers MSc degrees in History and Philosophy of Science and in the study of contemporary Science, Technology, and Society. An MPhil/PhD research degree is offered, too. UCL also contains a Centre for the History of Medicine. This operates a small teaching programme in History of Medicine.
 * University of Leeds has both undergraduate and graduate programmes in History and Philosophy of Science in the Department of Philosophy.
 * University of Manchester offers undergraduate modules and postgraduate study in History of Science, Technology and Medicine and is sponsored by the Wellcome Trust.
 * University of Oxford has a one-year graduate course in 'History of Science: Instruments, Museums, Science, Technology' associated with the Museum of the History of Science.
 * The London Centre for the History of Science, Medicine, and Technology – this Centre closed in 2013. It was formed in 1987 and ran a taught MSc programme, jointly taught by University College London's Department of Science and Technology Studies and Imperial College London. The Masters programme transferred to UCL.

United States
Academic study of the history of science as an independent discipline was launched by George Sarton at Harvard with his book Introduction to the History of Science (1927) and the Isis journal (founded in 1912). Sarton exemplified the early 20th century view of the history of science as the history of great men and great ideas. He shared with many of his contemporaries a Whiggish belief in history as a record of the advances and delays in the march of progress. The History of Science was not a recognized subfield of American history in this period, and most of the work was carried out by interested Scientists and Physicians rather than professional Historians. With the work of I. Bernard Cohen at Harvard, the history of Science became an established subdiscipline of history after 1945.

 * Arizona State University's Center for Biology and Society offers several paths for MS or PhD students who are interested in issues surrounding the history and philosophy of the science.
 * California Institute of Technology offers courses in the History and Philosophy of Science to fulfill its core humanities requirements.
 * Case Western Reserve University has an undergraduate interdisciplinary program in the History and Philosophy of Science and a graduate program in the History of Science, Technology, Environment, and Medicine (STEM).
 * Cornell University offers a variety of courses within the Science and Technology course.
 * Georgia Institute of Technology has an undergraduate and graduate program in the History of Technology and Society.
 * Harvard has an undergraduate and graduate program in History of Science
 * Indiana University offers undergraduate courses and a masters and PhD program in the History and Philosophy of Science.
 * Johns Hopkins University has an undergraduate and graduate program in the History of Science, Medicine, and Technology.
 * Lehigh University offers an undergraduate level STS concentration (founded in 1972) and a graduate program with emphasis on the History of Industrial America.
 * Massachusetts Institute of Technology has a Science, Technology, and Society program which includes HST.
 * Michigan State University offers an undergraduate major and minor in History, Philosophy, and Sociology of Science through its Lyman Briggs College.
 * New Jersey Institute of Technology has a Science, Technology, and Society program which includes the History of Science and Technology
 * Oregon State University offers a Masters and Ph.D. in History of Science through its Department of History.
 * Princeton University has a program in the History of Science.
 * Rensselaer Polytechnic Institute has a Science and Technology Studies department
 * Rutgers has a graduate Program in History of Science, Technology, Environment, and Health.
 * Stanford has a History and Philosophy of Science and Technology program.
 * Stevens Institute of Technology has an undergraduate and graduate program in the History of Science.
 * University of California, Berkeley offers a graduate degree in HST through its History program, and maintains a separate sub-department for the field.
 * University of California, Los Angeles has a relatively large group History of Science and Medicine faculty and graduate students within its History department, and also offers an undergraduate minor in the History of Science.
 * University of California, Santa Barbara has an interdisciplinary graduate program emphasis in Technology & Society through the Center for Information Technology & Society.
 * University of Chicago offers a B.A. program in the History, Philosophy, and Social Studies of Science and Medicine as well as M.A. and Ph.D. degrees through its Committee on the Conceptual and Historical Studies of Science.
 * University of Florida has a Graduate Program in 'History of Science, Technology, and Medicine' at the University of Florida provides undergraduate and graduate degrees.
 * University of Minnesota has a Ph.D. program in History of Science, Technology, and Medicine as well as undergraduate courses in these fields.
 * University of Oklahoma has an undergraduate minor and a graduate degree program in History of Science.
 * University of Pennsylvania has a program in History and Sociology of Science.
 * University of Pittsburgh's Department of History and Philosophy of Science offers graduate and undergraduate courses.
 * University of Puget Sound has a Science, Technology, and Society program, which includes the history of Science and Technology.
 * University of Wisconsin–Madison has a program in History of Science, Medicine and Technology. It offers M.A. and Ph.D. degrees as well as an undergraduate major.
 * Wesleyan University has a Science in Society program.
 * Yale University has a program in the History of Science and Medicine.

Prominent historians of the field
See also the list of George Sarton medalists.

 * Wiebe Bijker
 * Peter J. Bowler
 * Janet Browne
 * Stephen G. Brush
 * James Burke
 * Edwin Arthur Burtt (1892–1989)
 * Johann Beckmann (1739–1811)
 * Jim Bennett
 * Herbert Butterfield (1900–1979)
 * Martin Campbell-Kelly
 * Georges Canguilhem (1904–1995)
 * Allan Chapman
 * I. Bernard Cohen (1914–2003)
 * A. C. Crombie (1915–1996)
 * E. J. Dijksterhuis (1892–1965)
 * Pierre Duhem (1861–1916)
 * A. Hunter Dupree (1921–2019)
 * George Dyson
 * Jacques Ellul (1912–1994)
 * Eugene S. Ferguson (1916–2004)
 * Peter Galison
 * Sigfried Giedion
 * Charles Coulston Gillispie
 * Robert Gunther (1869–1940)
 * Paul Forman (historian)
 * Donna Haraway
 * Peter Harrison
 * Ahmad Y Hassan
 * John L. Heilbron
 * Boris Hessen
 * Reijer Hooykaas
 * David A. Hounshell
 * Thomas P. Hughes
 * Evelyn Fox Keller
 * Daniel Kevles
 * Alexandre Koyré (1892–1964)
 * Melvin Kranzberg
 * Thomas Kuhn
 * Deepak Kumar
 * Gilbert LaFreniere
 * Bruno Latour
 * David C. Lindberg
 * G. E. R. Lloyd
 * Jane Maienschein
 * Anneliese Maier
 * Leo Marx
 * Lewis Mumford (1895–1990)
 * John E. Murdoch (1927–2010)
 * Otto Neugebauer (1899–1990)
 * William R. Newman
 * David Noble
 * Ronald Numbers
 * David E. Nye
 * Abraham Pais (1918–2000)
 * Trevor Pinch
 * Theodore Porter
 * Lawrence M. Principe
 * Raúl Rojas
 * Michael Ruse
 * A. I. Sabra
 * Jan Sapp
 * George Sarton (1884–1956)
 * Simon Schaffer
 * Howard Segal (1948–2020)
 * Steven Shapin
 * Wolfgang Schivelbusch
 * Charles Singer (1876–1960)
 * Merritt Roe Smith
 * Stephen Snobelen
 * M. Norton Wise
 * Frances A. Yates (1899–1981)

Journals and periodicals

 * Annals of Science
 * The British Journal for the History of Science
 * Centaurus
 * Dynamis
 * History and Technology (magazine)
 * History of Science and Technology (journal)
 * History of Technology (book series)
 * Historical Studies in the Physical and Biological Sciences (HSPS)
 * Historical Studies in the Natural Sciences (HSNS)
 * HoST - Journal of History of Science and Technology
 * ICON
 * IEEE Annals of the History of Computing
 * Isis
 * Journal of the History of Biology
 * Journal of the History of Medicine and Allied Sciences
 * Notes and Records of the Royal Society
 * Osiris
 * Science & Technology Studies
 * Science in Context
 * Science, Technology, & Human Values
 * Social History of Medicine
 * Social Studies of Science
 * Technology and Culture
 * Transactions of the Newcomen Society
 * Historia Mathematica
 * Bulletin of the Scientific Instrument Society

Professional societies

 * The British Society for the History of Science (BSHS)
 * History of Science Society (HSS)
 * Newcomen Society
 * Society for the History of Technology (SHOT)
 * Society for the Social Studies of Science (4S)
 * Scientific Instrument Society

title: History of science and technology


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Holographic principle

The holographic principle is a property of string theories and a supposed property of quantum gravity that states that the description of a volume of space can be thought of as encoded on a lower-dimensional boundary to the region — such as a light-like boundary like a gravitational horizon. First proposed by Gerard 't Hooft, it was given a precise string theoretic interpretation by Leonard Susskind, who combined his ideas with previous ones of 't Hooft and Charles Thorn. Leonard Susskind said, "The three-dimensional world of ordinary experience––the universe filled with galaxies, stars, planets, houses, boulders, and people––is a hologram, an image of reality coded on a distant two-dimensional surface." As pointed out by Raphael Bousso, Thorn observed in 1978 that string theory admits a lower-dimensional description in which gravity emerges from it in what would now be called a holographic way. The prime example of holography is the AdS/CFT correspondence.

The holographic principle was inspired by black hole thermodynamics, which conjectures that the maximum entropy in any region scales with the radius squared, and not cubed as might be expected, so called Bekenstein bound. In the case of a black hole, the insight was that the information content of all the objects that have fallen into the hole might be entirely contained in surface fluctuations of the event horizon. The holographic principle resolves the black hole information paradox within the framework of string theory. However, there exist classical solutions to the Einstein equations that allow values of the entropy larger than those allowed by an area law (radius squared), hence in principle larger than those of a black hole. These are the so-called "Wheeler's bags of gold". The existence of such solutions conflicts with the holographic interpretation, and their effects in a quantum theory of gravity including the holographic principle are not yet fully understood.

High-level summary
The physical universe is widely seen to be composed of "matter" and "energy". In his 2003 article published in Scientific American magazine, Jacob Bekenstein speculatively summarized a current trend started by John Archibald Wheeler, which suggests scientists may "regard the physical world as made of information, with energy and matter as incidentals". Bekenstein asks "Could we, as William Blake memorably penned, 'see a world in a grain of sand', or is that idea no more than 'poetic license'?", referring to the holographic principle.

Unexpected connection
Bekenstein's topical overview "A Tale of Two Entropies" describes potentially profound implications of Wheeler's trend, in part by noting a previously unexpected connection between the world of information theory and classical physics. This connection was first described shortly after the seminal 1948 papers of American applied mathematician Claude Shannon introduced today's most widely used measure of information content, now known as Shannon entropy. As an objective measure of the quantity of information, Shannon entropy has been enormously useful, as the design of all modern communications and data storage devices, from cellular phones to modems to hard disk drives and DVDs, rely on Shannon entropy.

In thermodynamics (the branch of physics dealing with heat), entropy is popularly described as a measure of the "disorder" in a physical system of matter and energy. In 1877, Austrian physicist Ludwig Boltzmann described it more precisely in terms of the number of distinct microscopic states that the particles composing a macroscopic "chunk" of matter could be in, while still "looking" like the same macroscopic "chunk". As an example, for the air in a room, its thermodynamic entropy would equal the logarithm of the count of all the ways that the individual gas molecules could be distributed in the room, and all the ways they could be moving.

Energy, matter, and information equivalence
Shannon's efforts to find a way to quantify the information contained in, for example, a telegraph message, led him unexpectedly to a formula with the same form as Boltzmann's. In an article in the August 2003 issue of Scientific American titled "Information in the Holographic Universe", Bekenstein summarizes that "Thermodynamic entropy and Shannon entropy are conceptually equivalent: the number of arrangements that are counted by Boltzmann entropy reflects the amount of Shannon information one would need to implement any particular arrangement" of matter and energy. The only salient difference between the thermodynamic entropy of physics and Shannon's entropy of information is in the units of measure; the former is expressed in units of energy divided by temperature, the latter in essentially dimensionless "bits" of information.

The holographic principle states that the entropy of ordinary mass (not just black holes) is also proportional to surface area and not volume; that volume itself is illusory and the universe is really a hologram which is isomorphic to the information "inscribed" on the surface of its boundary.

The AdS/CFT correspondence
The anti-de Sitter/conformal field theory correspondence, sometimes called Maldacena duality (after ref. ) or gauge/gravity duality, is a conjectured relationship between two kinds of physical theories. On one side are anti-de Sitter spaces (AdS) which are used in theories of quantum gravity, formulated in terms of string theory or M-theory. On the other side of the correspondence are conformal field theories (CFT) which are quantum field theories, including theories similar to the Yang–Mills theories that describe elementary particles.

The duality represents a major advance in our understanding of string theory and quantum gravity. This is because it provides a non-perturbative formulation of string theory with certain boundary conditions and because it is the most successful realization of the holographic principle.

It also provides a powerful toolkit for studying strongly coupled quantum field theories. Much of the usefulness of the duality results from the fact that it is a strong-weak duality: when the fields of the quantum field theory are strongly interacting, the ones in the gravitational theory are weakly interacting and thus more mathematically tractable. This fact has been used to study many aspects of nuclear and condensed matter physics by translating problems in those subjects into more mathematically tractable problems in string theory.

The AdS/CFT correspondence was first proposed by Juan Maldacena in late 1997. Important aspects of the correspondence were elaborated in articles by Steven Gubser, Igor Klebanov, and Alexander Markovich Polyakov, and by Edward Witten. By 2015, Maldacena's article had over 10,000 citations, becoming the most highly cited article in the field of high energy physics.

Black hole entropy
An object with relatively high entropy is microscopically random, like a hot gas. A known configuration of classical fields has zero entropy: there is nothing random about electric and magnetic fields, or gravitational waves. Since black holes are exact solutions of Einstein's equations, they were thought not to have any entropy either.

But Jacob Bekenstein noted that this leads to a violation of the second law of thermodynamics. If one throws a hot gas with entropy into a black hole, once it crosses the event horizon, the entropy would disappear. The random properties of the gas would no longer be seen once the black hole had absorbed the gas and settled down. One way of salvaging the second law is if black holes are in fact random objects with an entropy that increases by an amount greater than the entropy of the consumed gas.

Given a fixed volume, a black hole whose event horizon encompasses that volume should be the object with the highest amount of entropy. Otherwise, suppose we have something with a larger entropy, then by throwing more mass into that something, we obtain a black hole with less entropy, violating the second law.

In a sphere of radius R, the entropy in a relativistic gas increases as the energy increases. The only known limit is gravitational; when there is too much energy the gas collapses into a black hole. Bekenstein used this to put an upper bound on the entropy in a region of space, and the bound was proportional to the area of the region. He concluded that the black hole entropy is directly proportional to the area of the event horizon. Gravitational time dilation causes time, from the perspective of a remote observer, to stop at the event horizon. Due to the natural limit on maximum speed of motion, this prevents falling objects from crossing the event horizon no matter how close they get to it. Since any change in quantum state requires time to flow, all objects and their quantum information state stay imprinted on the event horizon. Bekenstein concluded that from the perspective of any remote observer, the black hole entropy is directly proportional to the area of the event horizon.

Stephen Hawking had shown earlier that the total horizon area of a collection of black holes always increases with time. The horizon is a boundary defined by light-like geodesics; it is those light rays that are just barely unable to escape. If neighboring geodesics start moving toward each other they eventually collide, at which point their extension is inside the black hole. So the geodesics are always moving apart, and the number of geodesics which generate the boundary, the area of the horizon, always increases. Hawking's result was called the second law of black hole thermodynamics, by analogy with the law of entropy increase.

At first, Hawking did not take the analogy too seriously. He argued that the black hole must have zero temperature, since black holes do not radiate and therefore cannot be in thermal equilibrium with any black body of positive temperature. Then he discovered that black holes do radiate. When heat is added to a thermal system, the change in entropy is the increase in mass–energy divided by temperature:

{\rm d}S = \frac{{\rm\delta }M \ c^2}{T}. $$ (Here the term δM c2 is substituted for the thermal energy added to the system, generally by non-integrable random processes, in contrast to dS, which is a function of a few "state variables" only, i.e. in conventional thermodynamics only of the Kelvin temperature T and a few additional state variables, such as the pressure.)

If black holes have a finite entropy, they should also have a finite temperature. In particular, they would come to equilibrium with a thermal gas of photons. This means that black holes would not only absorb photons, but they would also have to emit them in the right amount to maintain detailed balance.

Time-independent solutions to field equations do not emit radiation, because a time-independent background conserves energy. Based on this principle, Hawking set out to show that black holes do not radiate. But, to his surprise, a careful analysis convinced him that they do, and in just the right way to come to equilibrium with a gas at a finite temperature. Hawking's calculation fixed the constant of proportionality at 1/4; the entropy of a black hole is one quarter its horizon area in Planck units.

The entropy is proportional to the logarithm of the number of microstates, the enumerated ways a system can be configured microscopically while leaving the macroscopic description unchanged. Black hole entropy is deeply puzzling – it says that the logarithm of the number of states of a black hole is proportional to the area of the horizon, not the volume in the interior.

Later, Raphael Bousso came up with a covariant version of the bound based upon null sheets.

Black hole information paradox
Hawking's calculation suggested that the radiation which black holes emit is not related in any way to the matter that they absorb. The outgoing light rays start exactly at the edge of the black hole and spend a long time near the horizon, while the infalling matter only reaches the horizon much later. The infalling and outgoing mass/energy interact only when they cross. It is implausible that the outgoing state would be completely determined by some tiny residual scattering.

Hawking interpreted this to mean that when black holes absorb some photons in a pure state described by a wave function, they re-emit new photons in a thermal mixed state described by a density matrix. This would mean that quantum mechanics would have to be modified because, in quantum mechanics, states which are superpositions with probability amplitudes never become states which are probabilistic mixtures of different possibilities.

Troubled by this paradox, Gerard 't Hooft analyzed the emission of Hawking radiation in more detail. He noted that when Hawking radiation escapes, there is a way in which incoming particles can modify the outgoing particles. Their gravitational field would deform the horizon of the black hole, and the deformed horizon could produce different outgoing particles than the undeformed horizon. When a particle falls into a black hole, it is boosted relative to an outside observer, and its gravitational field assumes a universal form. 't Hooft showed that this field makes a logarithmic tent-pole shaped bump on the horizon of a black hole, and like a shadow, the bump is an alternative description of the particle's location and mass. For a four-dimensional spherical uncharged black hole, the deformation of the horizon is similar to the type of deformation which describes the emission and absorption of particles on a string-theory world sheet. Since the deformations on the surface are the only imprint of the incoming particle, and since these deformations would have to completely determine the outgoing particles, 't Hooft believed that the correct description of the black hole would be by some form of string theory.

This idea was made more precise by Leonard Susskind, who had also been developing holography, largely independently. Susskind argued that the oscillation of the horizon of a black hole is a complete description of both the infalling and outgoing matter, because the world-sheet theory of string theory was just such a holographic description. While short strings have zero entropy, he could identify long highly excited string states with ordinary black holes. This was a deep advance because it revealed that strings have a classical interpretation in terms of black holes.

This work showed that the black hole information paradox is resolved when quantum gravity is described in an unusual string-theoretic way assuming the string-theoretical description is complete, unambiguous and non-redundant. The space-time in quantum gravity would emerge as an effective description of the theory of oscillations of a lower-dimensional black-hole horizon, and suggest that any black hole with appropriate properties, not just strings, would serve as a basis for a description of string theory.

In 1995, Susskind, along with collaborators Tom Banks, Willy Fischler, and Stephen Shenker, presented a formulation of the new M-theory using a holographic description in terms of charged point black holes, the D0 branes of type IIA string theory. The matrix theory they proposed was first suggested as a description of two branes in 11-dimensional supergravity by Bernard de Wit, Jens Hoppe, and Hermann Nicolai. The later authors reinterpreted the same matrix models as a description of the dynamics of point black holes in particular limits. Holography allowed them to conclude that the dynamics of these black holes give a complete non-perturbative formulation of M-theory. In 1997, Juan Maldacena gave the first holographic descriptions of a higher-dimensional object, the 3+1-dimensional type IIB membrane, which resolved a long-standing problem of finding a string description which describes a gauge theory. These developments simultaneously explained how string theory is related to some forms of supersymmetric quantum field theories.

Limit on information density
Information content is defined as the logarithm of the reciprocal of the probability that a system is in a specific microstate, and the information entropy of a system is the expected value of the system's information content. This definition of entropy is equivalent to the standard Gibbs entropy used in classical physics. Applying this definition to a physical system leads to the conclusion that, for a given energy in a given volume, there is an upper limit to the density of information (the Bekenstein bound) about the whereabouts of all the particles which compose matter in that volume. In particular, a given volume has an upper limit of information it can contain, at which it will collapse into a black hole.

This suggests that matter itself cannot be subdivided infinitely many times and there must be an ultimate level of fundamental particles. As the degrees of freedom of a particle are the product of all the degrees of freedom of its sub-particles, were a particle to have infinite subdivisions into lower-level particles, the degrees of freedom of the original particle would be infinite, violating the maximal limit of entropy density. The holographic principle thus implies that the subdivisions must stop at some level.

The most rigorous realization of the holographic principle is the AdS/CFT correspondence by Juan Maldacena. However, J. David Brown and Marc Henneaux had rigorously proved already in 1986, that the asymptotic symmetry of 2+1 dimensional gravity gives rise to a Virasoro algebra, whose corresponding quantum theory is a 2-dimensional conformal field theory.

Experimental tests
The Fermilab physicist Craig Hogan claims that the holographic principle would imply quantum fluctuations in spatial position that would lead to apparent background noise or "holographic noise" measurable at gravitational wave detectors, in particular GEO 600. However these claims have not been widely accepted, or cited, among quantum gravity researchers and appear to be in direct conflict with string theory calculations.

Analyses in 2011 of measurements of gamma ray burst GRB 041219A in 2004 by the INTEGRAL space observatory launched in 2002 by the European Space Agency shows that Craig Hogan's noise is absent down to a scale of 10−48 meters, as opposed to the scale of 10−35 meters predicted by Hogan, and the scale of 10−16 meters found in measurements of the GEO 600 instrument. Research continued at Fermilab under Hogan as of 2013.

Jacob Bekenstein claimed to have found a way to test the holographic principle with a tabletop photon experiment.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Holographic principle


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Hamilton, Ontario

Hamilton is a port city in the Canadian province of Ontario. Hamilton has a population of 569,353, and its census metropolitan area, which encompasses Burlington and Grimsby, has a population of 785,184. The city is situated approximately 45 km southwest of Toronto in the Greater Toronto and Hamilton Area (GTHA).

Conceived by George Hamilton when he purchased the Durand farm shortly after the War of 1812, the town of Hamilton became the centre of a densely populated and industrialized region at the west end of Lake Ontario known as the Golden Horseshoe. On January 1, 2001, the current boundaries of Hamilton were created through the amalgamation of the original city with other municipalities of the Regional Municipality of Hamilton–Wentworth. Residents of the city are known as Hamiltonians.

Traditionally, the local economy has been led by the steel and heavy manufacturing industries. During the 2010s, a shift toward the service sector occurred, such as health and sciences. Hamilton is home to the Royal Botanical Gardens, the Canadian Warplane Heritage Museum, the Bruce Trail, McMaster University, Mohawk College, and Redeemer University. McMaster University is ranked 4th in Canada and 69th in the world by Times Higher Education Rankings 2021.

History
In pre-colonial times, the Neutral First Nation used much of the land. They were gradually driven out by the Five (later Six) Nations (Iroquois) who were allied with the British against the Huron and their French allies. The hamlet of Westover was built in an area that was originally a Seneca Iroquois tribal village, Tinawatawa, which was first visited by the French in September 1699.

After the American Revolutionary War, about 10,000 United Empire Loyalists left the United States to settle in Upper Canada, now southern Ontario. In 1792, the Crown purchased the land on which Hamilton now stands from the Mississaugas in Treaty 3, also known as the Between the Lakes Purchase. The Crown granted the Loyalists lands from this purchase to encourage settlement in the region. These new settlers were soon followed by many more Americans, attracted by the availability of inexpensive, arable land. At the same time, large numbers of Iroquois who had allied with Britain arrived from the United States and were settled on reserves west of Lake Ontario as compensation for lands they lost in what was now the United States. During the War of 1812, British regulars and local militia defeated invading American troops at the Battle of Stoney Creek, fought in what is now a park in eastern Hamilton.

The town of Hamilton was conceived by George Hamilton (a son of a Queenston entrepreneur and founder, Robert Hamilton), when he purchased farm holdings of James Durand, the local member of the Legislative Assembly of Upper Canada, shortly after the War of 1812. Nathaniel Hughson, a property owner to the north, cooperated with George Hamilton to prepare a proposal for a courthouse and jail on Hamilton's property. Hamilton offered the land to the crown for the future site. Durand was empowered by Hughson and Hamilton to sell property holdings which later became the site of the town. As he had been instructed, Durand circulated the offers at York during a session of the Legislative Assembly, which established a new Gore District, of which the Hamilton townsite was a member.

Initially, this town was not the most important centre of the Gore District. An early indication of Hamilton's sudden prosperity occurred in 1816 when it was chosen over Ancaster, Ontario to be the new Gore District's administrative centre. Another dramatic economic turnabout for Hamilton occurred in 1832 when a canal was finally cut through the outer sand bar that enabled Hamilton to become a major port. A permanent jail was not constructed until 1832, when a cut-stone design was completed on Prince's Square, one of the two squares created in 1816. Subsequently, the first police board and the town limits were defined by statute on February 13, 1833. Official city status was achieved on June 9, 1846, by an act of Parliament of the Province of Canada.

By 1845, the population was 6,475. In 1846, there were useful roads to many communities as well as stagecoaches and steamboats to Toronto, Queenston, and Niagara. Eleven cargo schooners were owned in Hamilton. Eleven churches were in operation. A reading room provided access to newspapers from other cities and from England and the U.S. In addition to stores of all types, four banks, tradesmen of various types, and sixty-five taverns, industry in the community included three breweries, ten importers of dry goods and groceries, five importers of hardware, two tanneries, three coachmakers, and a marble and a stone works. As the city grew, several prominent buildings were constructed in the late 19th century, including the Grand Lodge of Canada in 1855, West Flamboro Methodist Church in 1879 (later purchased by Dufferin Masonic Lodge in 1893), a public library in 1890, and the Right House department store in 1893. The first commercial telephone service in Canada, the first telephone exchange in the British Empire, and the second telephone exchange in all of North America were each established in the city between 1877 and 1878. The city had several interurban electric street railways and two inclines, all powered by the Cataract Power Co.

Though suffering through the Hamilton Street Railway strike of 1906, with industrial businesses expanding, Hamilton's population doubled between 1900 and 1914. Two steel manufacturing companies, Stelco and Dofasco, were formed in 1910 and 1912, respectively. Procter & Gamble and the Beech-Nut Packing Company opened manufacturing plants in 1914 and 1922, respectively, their first outside the US. In June and July 1916, the a strike of up to 2,000 machinists was caused by a failure of employers to improve working conditions or pay during a booming World War I economy. The strike disrupted production at many of the largest manufacturers and was the largest dispute in the city's history. Population and economic growth continued until the 1960s. In 1929 the city's first high-rise building, the Pigott Building, was constructed; in 1930 McMaster University moved from Toronto to Hamilton, in 1934 the second Canadian Tire store in Canada opened here; in 1940 the airport was completed; and in 1948, the Studebaker assembly line was constructed. Infrastructure and retail development continued, with the Burlington Bay James N. Allan Skyway opening in 1958, and the first Tim Hortons store in 1964.

Since then, many of the large industries have moved or shut down operations in a restructuring that also affected the United States. In 1997, there was a devastating fire at the Plastimet plastics plant. Approximately 300 firefighters battled the blaze, and many sustained severe chemical burns and inhaled volatile organic compounds when at least 400 tonnes of PVC plastic were consumed in the fire.

On January 1, 2001, the new city of Hamilton was formed from the amalgamation of Hamilton and its five neighbouring municipalities: Ancaster, Dundas, Flamborough, Glanbrook, and Stoney Creek. Before amalgamation, the "old" City of Hamilton had 331,121 residents and was divided into 100 neighbourhoods. The former region of Hamilton-Wentworth had a population of 490,268. The amalgamation created a single-tier municipal government ending subsidization of its suburbs. The new amalgamated city had 519,949 people in more than 100 neighbourhoods, and surrounding communities.

The city was impacted by a widespread blackout in 2003 and a tornado in 2005. In 2007, the Red Hill Valley Parkway opened after extensive delays. The Stelco mills were idled in 2010 and permanently closed in 2013. This closure capped a significant shift in the city's economy: the percentage of the population employed in manufacturing declined from 22 to 12 percent between 2003 and 2013.

Geography
Hamilton is in Southern Ontario on the western end of the Niagara Peninsula and wraps around the westernmost part of Lake Ontario; most of the city, including the downtown section, is on the south shore. Hamilton is in the geographic centre of the Golden Horseshoe. Its major physical features are Hamilton Harbour, marking the northern limit of the city, and the Niagara Escarpment running through the middle of the city across its entire breadth, bisecting the city into "upper" and "lower" parts. The maximum high point is 250m (820') above the level of Lake Ontario.

According to all records from local historians, this district was called Attiwandaronia by the native Neutral people. Hamilton is one of 11 cities showcased in the book, Green City: People, Nature & Urban Places by Quebec author Mary Soderstrom, which examines the city as an example of an industrial powerhouse co-existing with nature. Soderstrom credits Thomas McQuesten and family in the 1930s who "became champions of parks, greenspace and roads" in Hamilton.

Hamilton Harbour is a natural harbour with a large sandbar called the Beachstrip. This sandbar was deposited during a period of higher lake levels during the last ice age and extends southeast through the central lower city to the escarpment. Hamilton's deep sea port is accessed by ship canal through the beach strip into the harbour and is traversed by two bridges, the QEW's Burlington Bay James N. Allan Skyway and the lower Canal Lift Bridge.

Between 1788 and 1793, the townships at the Head-of-the-Lake were surveyed and named. The area was first known as The Head-of-the-Lake for its location at the western end of Lake Ontario. John Ryckman, born in Barton township (where present day downtown Hamilton is), described the area in 1803 as he remembered it: "The city in 1803 was all forest. The shores of the bay were difficult to reach or see because they were hidden by a thick, almost impenetrable mass of trees and undergrowth".

George Hamilton, a settler and local politician, established a town site in the northern portion of Barton Township in 1815. He kept several east–west roads which were originally Indian trails, but the north–south streets were on a regular grid pattern. Streets were designated "East" or "West" if they crossed James Street or Highway 6. Streets were designated "North" or "South" if they crossed King Street or Highway 8. The townsite's design, likely conceived in 1816, was commonplace. George Hamilton employed a grid street pattern used in most towns in Upper Canada and throughout the American frontier. The eighty original lots had frontages of fifty feet; each lot faced a broad street and backed onto a twelve-foot lane. It took at least a decade to sell all the original lots, but the construction of the Burlington Canal in 1823, and a new court-house in 1827 encouraged Hamilton to add more blocks around 1828–9. At this time he included a market square in an effort to draw commercial activity onto his lands, but the town's natural growth occurred to the north of Hamilton's plot.

The Hamilton Conservation Authority owns, leases or manages about 4500 ha of land with the city operating 1077 ha of parkland at 310 locations. Many of the parks are along the Niagara Escarpment, which runs from Tobermory at the tip of the Bruce Peninsula in the north, to Queenston at the Niagara River in the south, and provides views of the cities and towns at Lake Ontario's western end. The hiking path Bruce Trail runs the length of the escarpment. Hamilton is home to more than 100 waterfalls and cascades, most of which are on or near the Bruce Trail as it winds through the Niagara Escarpment. Visitors can often be seen swimming in the waterfalls during the summertime, although it is strongly recommended to stay away from the water: much of the watershed of the Chedoke and Red Hill creeks originates in storm sewers running beneath neighbourhoods atop the Niagara escarpment, and water quality in many of Hamilton's waterfalls is seriously degraded. High e. coli counts are regularly observed through testing by McMaster University near many of Hamilton's waterfalls, sometimes exceeding the provincial limits for recreational water use by as much as 400 times. The storm sewers in upstream neighbourhoods carry polluted runoff from streets and parking lots, as well as occasional raw sewage from sanitary lines that were improperly connected to the storm sewers instead of the separate sanitary sewer system. Notably, in March 2020, it was revealed that as much as 24 billion litres of untreated wastewater has been leaking into the Chedoke creek and Cootes' Paradise areas since at least 2014 due to insufficiencies in the city's sewerage and storm water management systems.

Climate
Hamilton's climate is humid-continental, characterized by changeable weather patterns. In the Köppen classification, Hamilton it is on the Dfb/Dfa border found in southern Ontario because the average temperature in July is 22.0 C. However, its climate is moderate compared with most of Canada. The airport's open, rural location and higher altitude results in lower temperatures, generally windier conditions, and higher snowfall amounts than lower, built-up areas of the city. The highest temperature ever recorded in Hamilton was 41.1 °C (106 °F) on July 14, 1868. The coldest temperature ever recorded was −30.6 °C (−23 °F) on January 25, 1884. In 2023, it was found that the city has areas of poor air quality with a high concentration of benzo(a)pyrene, particularly in neighbourhoods near industrial sites.

Economy

Manufacturing is important to Ontario's economy, and the Toronto–Hamilton region is Canada's most industrialized area. The area from Oshawa, Ontario around the west end of Lake Ontario to Niagara Falls, with Hamilton at its centre, is known as the Golden Horseshoe and had a population of approximately 8.1 million people in 2006.

With sixty percent of Canada's steel produced in Hamilton by Stelco and Dofasco, the city has become known as the Steel Capital of Canada. After nearly declaring bankruptcy, Stelco returned to profitability in 2004. On August 26, 2007 United States Steel Corporation acquired Stelco for C$38.50 in cash per share, owning more than 76 percent of Stelco's outstanding shares. On September 17, 2014, US Steel Canada announced it was applying for bankruptcy protection and it would close its Hamilton operations.

A stand-alone subsidiary of ArcelorMittal, the world's largest steel producer, Dofasco produces products for the automotive, construction, energy, manufacturing, pipe and tube, appliance, packaging, and steel distribution industries. It has approximately 7,300 employees at its Hamilton plant, and the four million tons of steel it produces each year is about 30% of Canada's flat-rolled sheet steel shipments. Dofasco was North America's most profitable steel producer in 1999, the most profitable in Canada in 2000, and a long-time member of the Dow Jones Sustainability World Index. Ordered by the U.S. Department of Justice to divest itself of the Canadian company, ArcelorMittal has been allowed to retain Dofasco provided it sells several of its American assets.

Demographics
In the 2021 Census of Population conducted by Statistics Canada, Hamilton had a population of $569,353$ living in $222,807$ of its $233,564$ total private dwellings, a change of NaN% from its 2016 population of $536,917$. With a land area of 1118.31 km2, it had a population density of in 2021.

At the census metropolitan area (CMA) level in the 2021 census, the Hamilton CMA had a population of $785,184$ living in $307,382$ of its $320,081$ total private dwellings, a change of NaN% from its 2016 population of $747,545$. With a land area of 1373.15 km2, it had a population density of in 2021.

In the 2016 Canadian census, 24.69% of the city's population was not born in Canada. Hamilton is home to 26,330 immigrants who arrived in Canada between 2001 and 2010 and 13,150 immigrants who arrived between 2011 and 2016. In February 2014, the city's council voted to declare Hamilton a sanctuary city, offering municipal services to undocumented immigrants at risk of deportation.

Children aged 14 years and under accounted for 16.23% of the city's population, a decline of 1.57% from the 2011 census. Hamiltonians aged 65 years and older constituted 17.3% of the population, an increase of 2.4% since 2011. The city's average age is 41.3 years. 54.9% of Hamiltonians are married or in a common-law relationship, while 6.4% of city residents are divorced. Same-sex couples (married or in common-law relationships) constitute 0.8% (2,710 individuals) of the partnered population in Hamilton.

Environics Analytics, a geodemographic marketing firm that created 66 different "clusters" of people complete with profiles of how they live, what they think and what they consume, sees a future Hamilton with younger upscale Hamiltonians — who are tech-savvy and university-educated — choosing to live in the downtown and surrounding areas rather than just visiting intermittently. More two and three-storey townhouses and apartments will be built on downtown lots; small condos will be built on vacant spaces in areas such as Dundas, Ainslie Wood and Westdale to accommodate newly retired seniors. Furthermore, additional retail and commercial zones will be created.

Ethnicity
Hamilton maintains significant Italian, English, Scottish, German and Irish ancestry. 130,705 Hamiltonians claim English heritage, while 98,765 indicate their ancestors arrived from Scotland, 87,825 from Ireland, 62,335 from Italy, and 50,400 from Germany. The top countries of birth for the newcomers living in Hamilton in the 1990s were: former Yugoslavia, Poland, India, China, the Philippines, and Iraq.

Hamilton also has a notable French community for which provincial services are offered in French. In Ontario, urban centres where there are at least 5,000 Francophones are designated areas where bilingual provincial services have to be offered. As per the 2016 census, the Francophone community maintains a population of 6,760, while 30,530 residents, or 5.8% of the city's population, have knowledge of both official languages. The Franco-Ontarian community of Hamilton boasts two school boards, the public Conseil scolaire Viamonde and the Catholic Conseil scolaire catholique MonAvenir, which operate five schools (2 secondary and 3 elementary). Additionally, the city maintains a Francophone community health centre that is part of the LHIN (Centre de santé communautaire Hamilton/Niagara), a cultural centre (Centre français Hamilton), three daycare centres, a provincially funded employment centre (Options Emploi), a community college site (Collège Boréal) and a community organization that supports the development of the francophone community in Hamilton (ACFO Régionale Hamilton).

Religion
According to the 2021 census, religious groups in Hamilton included:
 * Christianity (309,780 persons or 55.2%)
 * Irreligion (183,965 persons or 32.8%)
 * Islam (37,980 persons or 6.8%)
 * Hinduism (10,200 persons or 1.8%)
 * Sikhism (7,270 persons or 1.3%)
 * Buddhism (4,765 persons or 0.8%)
 * Judaism (3,045 persons or 0.5%)
 * Indigenous Spirituality (375 persons or 0.1%)
 * Other (3,535 persons or 0.6%)

The most described religion in Hamilton is Christianity although other religions brought by immigrants are also growing. The 2011 census indicates that 67.6% of the population adheres to a Christian denomination, with Catholics being the largest at 34.3% of the city's population. The Christ the King Cathedral is the seat of the Diocese of Hamilton. Other denominations include the United Church (6.5%), Anglican (6.4%), Presbyterian (3.1%), Christian Orthodox (2.9%), and other denominations (9.8%). Other religions with significant populations include Islam (3.7%), Buddhist (0.9%), Sikh (0.8%), Hindu (0.8%), and Jewish (0.7%). Those with no religious affiliation accounted for 24.9% of the population.

Government
Citizens of Hamilton are represented at all three levels of Canadian government: federal, provincial, and municipal. Hamilton is represented in the Parliament of Canada by five members of Parliament and in the Legislature of Ontario by five members of Provincial Parliament.

Hamilton's municipal government has a mayor, elected citywide, and 15 city councillors—one per city ward—to serve on the Hamilton City Council. The province grants the Hamilton City Council authority to govern through the Municipal Act of Ontario. Hamilton's current mayor is Andrea Horwath, elected on October 24, 2022. Hamilton's next municipal election will be held in 2026.

Hamilton is served by four school boards: the English language Hamilton-Wentworth District School Board and Hamilton-Wentworth Catholic District School Board and the French language Conseil scolaire Viamonde and Conseil scolaire catholique MonAvenir. Each school board is governed by trustees. The English language school boards are represented by trustees elected from wards in Hamilton. The HWDSB has 11 trustees and the HWCDB has 9 trustees. The French language school boards are represented by one trustee each from Hamilton and the surrounding area. The Canadian Military maintains a presence in Hamilton, with the John Weir Foote Armoury in the downtown core on James Street North, housing the Royal Hamilton Light Infantry as well as the 11th Field Hamilton-Wentworth Battery and the Argyll and Sutherland Highlanders of Canada. The Hamilton Reserve Barracks on Pier Nine houses the naval reserve division HMCS Star, 23 Service Battalion and the 23 Field Ambulance.

Crime
The Criminal Code of Canada is the chief piece of legislation defining criminal conduct and penalty. The Hamilton Police Service is chiefly responsible for the enforcement of federal and provincial law. Although the Hamilton Police Service has authority to enforce, bylaws passed by the Hamilton City Council are mainly enforced by Provincial Offences Officers employed by the City of Hamilton.

In 2020, the city saw 18 murders and 51 shootings (up from 47 in 2019), the most shootings the city seen in at least a decade. 2021 saw the homicides in the city increase to 20, giving the city a rate of around 3.5 per 100,000 residents. Hamilton ranked first in Canada for police-reported hate crimes in 2016, with 12.5 hate crimes per 100,000 population. Organized crime also has a notable presence in Hamilton with three centralized Mafia organizations: the Luppino crime family, the Papalia crime family, and the Musitano crime family. Street gangs such as the Original/Oriental Blood Brothers & the Oriole Crescent Crips, and biker crews such as Satan's Choice MC and the Hells Angels also have presence in Hamilton.

Culture

Hamilton's local attractions include the Canadian Warplane Heritage Museum, the HMCS Haida National Historic Site, Dundurn Castle (the residence of an Allan MacNab, the 8th Premier of Canada West), the Royal Botanical Gardens, the Canadian Football Hall of Fame, the African Lion Safari Park, the Cathedral of Christ the King, the Workers' Arts and Heritage Centre, and the Hamilton Museum of Steam & Technology.

, there are 40 pieces in the city's Public Art Collection. The works are owned and maintained by the city. Founded in 1914, the Art Gallery of Hamilton is Ontario's third largest public art gallery. The gallery has over 9,000 works in its permanent collection that focus on three areas: 19th-century European, Historical Canadian and Contemporary Canadian. The McMaster Museum of Art (MMA), founded at McMaster University in 1967, houses and exhibits the university's art collection of more than 7,000 objects.

Supercrawl is a large community arts and music festival that takes place in September in the James Street North area of the city. In 2018, Supercrawl celebrated its 10th anniversary with over 220,000 visitors. In March 2015, Hamilton was host to the JUNO Awards.

Growth in the arts and culture sector has garnered media attention for Hamilton. A 2006 article in The Globe and Mail, entitled "Go West, Young Artist", focused on Hamilton's growing art scene. The Factory: Hamilton Media Arts Centre, opened a new home on James Street North in 2006. Art galleries have sprung up on streets across the city: James Street, King William Street, Locke Street and King Street. The opening of the Downtown Arts Centre on Rebecca Street has spurred creative activities in the core. The Community Centre for Media Arts (CCMA) continues to operate in downtown Hamilton. The CCMA works with marginalized populations and combines new media services with arts education and skills development programming.

Sports
Hamilton hosted Canada's first major international athletic event, the first Commonwealth Games (then called the British Empire Games) in 1930. Hamilton bid for the Commonwealth Games in 2010 but lost to New Delhi. On November 7, 2009, in Guadalajara, Mexico, it was announced Toronto would host the 2015 Pan Am Games after beating out two rival South American cities, Lima, Peru, and Bogotá, Colombia. The city of Hamilton co-hosted the Games with Toronto. Hamilton Mayor Fred Eisenberger said "the Pan Am Games will provide a 'unique opportunity for Hamilton to renew major sport facilities giving Hamiltonians a multi-purpose stadium, a 50-metre swimming pool, and an international-calibre velodrome to enjoy for generations to come'." Hamilton's major sports complexes include Tim Hortons Field and FirstOntario Centre.

Hamilton is represented by the Tiger-Cats in the Canadian Football League. The team traces its origins to the 1869 "Hamilton Foot Ball Club". Hamilton is also home to the Canadian Football Hall of Fame museum. The museum hosts an annual induction event in a week-long celebration that includes school visits, a golf tournament, a formal induction dinner and concludes with the Hall of Fame game involving the local CFL Hamilton Tiger-Cats at Tim Hortons Field. The 109th championship game of the Canadian Football League, the Grey Cup, is scheduled to be played in Hamilton in 2021.

In 2019, Forge FC debuted as Hamilton's soccer team in the Canadian Premier League. The team plays at Tim Hortons Field and shares the venue with the Tiger-Cats. They finished their inaugural season as champions of the league.

In 2019, the Hamilton Honey Badgers debuted as Hamilton's basketball team in the Canadian Elite Basketball League. The team played its home games at the FirstOntario Centre. In 2022, the Honey Badgers relocated to Brampton, Ontario due to the renovations occurring at FirstOntarioCentre.

Since 1958, the Hamilton Cardinals have been Hamilton's baseball team in the Intercounty Baseball League. The team has played its home games at Bernie Arbour Memorial Stadium since 1971.

The Around the Bay Road Race circumnavigates Hamilton Harbour. Although it is not a marathon distance, it is the longest continuously held long-distance foot race in North America. The local newspaper also hosts the amateur Spectator Indoor Games.

In addition to team sports, Hamilton is home to an auto race track, Flamboro Speedway and Canada's fastest half-mile harness horse racing track, Flamboro Downs. Another auto race track, Cayuga International Speedway, is near Hamilton in the Haldimand County community of Nelles Corners, between Hagersville and Cayuga.

Education
Hamilton is home to several post-secondary institutions.
 * McMaster University moved to the city in 1930 and now has some 30,000 students, of which almost two-thirds come from outside the Hamilton region.
 * Brock University of St. Catharines, Ontario has a satellite campus used primarily for teacher education in Hamilton.
 * McMaster Divinity College, a Christian seminary affiliated with the Baptist Convention of Ontario and Quebec since 1957. It is located on the McMaster University campus and it is affiliated with the university.
 * Mohawk College of Applied Arts and Technology since 1967 with 10,000 full-time, 40,000 part-time, and 3,000 apprentice students.
 * Redeemer University, a private Christian liberal arts and science university opened in 1982.

Four school boards administer public education for students from kindergarten through high school. The Hamilton-Wentworth District School Board manages 93 public schools, while the Hamilton-Wentworth Catholic District School Board operates 57 schools in the greater Hamilton area. The Conseil scolaire Viamonde operates one elementary and one secondary school (École secondaire Georges-P.-Vanier) in the area, and the Conseil scolaire catholique MonAvenir operates two elementary schools and one secondary school.

Calvin Christian School, Providence Christian School and Timothy Christian School are independent Christian elementary schools. Hamilton District Christian High School, Rehoboth Christian High School and Guido de Bres Christian High School are independent Christian high schools in the area. Both HDCH and Guido de Brès participate in the city's interscholastic athletics. Hillfield Strathallan College is on the West Hamilton mountain and is a CAIS member, non-profit school for children from early Montessori ages through grade twelve and has around 1,300 students. Columbia International College is Canada's largest private boarding high school, with 1,700 students from 73 countries.

The Dundas Valley School of Art is an independent art school founded in the city in 1964. In 1998, as a joint venture with McMaster University, a full-time diploma program was launched for students. The Hamilton Conservatory for the Arts is home to many of the area's young actors, dancers, musicians, singers and visual artists. The school is known for having a keyboard studio, dance studios, art and sculpting studios, gallery space and a 300-seat recital hall.

Hamilton is home to two think tanks, the Centre for Cultural Renewal and Cardus, which deals with social architecture, culture, urbanology, economics and education and also publishes the LexView Policy Journal and Comment Magazine.

Transportation
The primary highways serving Hamilton are Highway 403, the QEW, the Lincoln M. Alexander Parkway, and the Red Hill Valley Parkway. Other highways connecting Hamilton include Highway 5, Highway 6 and Highway 8. Public transportation is provided by the Hamilton Street Railway, which operates an extensive local bus system. Hamilton and Metrolinx will build a provincially-funded LRT line (Hamilton LRT) in the early 2020s. Intercity public transportation, including frequent service to Toronto, is provided by GO Transit. The Hamilton GO Centre, formerly the Toronto, Hamilton and Buffalo Railway station, is a commuter rail station on the Lakeshore West line of GO Transit. While Hamilton is not directly served by intercity rail, the Lakeshore West line does offer an off-peak bus connection and a peak-hours rail connection to Aldershot station in Burlington, which doubles as the VIA Rail station for both Burlington and Hamilton.

In the 1940s, the John C. Munro Hamilton International Airport was a wartime air force training station. Today, managed by TradePort International Corporation, passenger traffic at the Hamilton terminal has grown from 90,000 in 1996 to approximately 900,000 in 2002 with mostly domestic and vacation destinations in the United States, Mexico and Central America. The airport's mid-term growth target for its passenger service is five million air travellers annually. The airport's air cargo sector has 24–7 operational capability and strategic geographic location, allowing its capacity to increase by 50% since 1996; 91,000 metric tonnes (100,000 tons) of cargo passed through the airport in 2002. Courier companies with operations at the airport include United Parcel Service and Cargojet Canada. In 2003, the city began developing a 30-year growth management strategy which called, in part, for a massive aerotropolis industrial park centred on Hamilton Airport. Advocates of the aerotropolis proposal, now known as the Airport Employment Growth District, tout it as a solution to the city's shortage of employment lands. The closest other international airport to Hamilton is Toronto Pearson International Airport, located northeast of the city in Mississauga.

A report by Hemson Consulting identified an opportunity to develop 1000 ha of greenfields (the size of the Royal Botanical Gardens) that could create an estimated 90,000 jobs by 2031. A proposed aerotropolis industrial park at Highway 6 and 403, has been debated at City Hall for years. Opponents feel the city needs to do more investigation about the cost to taxpayers.

Hamilton also plays a major role in Ontario's marine shipping industry as the Port of Hamilton is Ontario's busiest port handling between 9 and 12 million tonnes of cargo annually.

Major highways

 * RHVP_Shield.png Red Hill Valley Parkway
 * LINC_Shield.png Lincoln M. Alexander Parkway
 * RHVP_Shield.png Red Hill Valley Parkway
 * LINC_Shield.png Lincoln M. Alexander Parkway

Health
The city is served by the Hamilton Health Sciences hospital network of five hospitals with more than 1,100 beds: Hamilton General Hospital, Juravinski Hospital, McMaster University Medical Centre (which includes McMaster Children's Hospital), St. Peter's Hospital and West Lincoln Memorial Hospital. Other buildings under Hamilton Health Sciences include Juravinski Cancer Centre, Regional Rehabilitation Centre, Ron Joyce Children's Health Centre, and the West End Clinic and Urgent Care Centre. Hamilton Health Sciences is the largest employer in the Hamilton area and serves as academic teaching hospital affiliated with McMaster University and Mohawk College. The only hospital in Hamilton not under Hamilton Health Sciences is St. Joseph's Healthcare Hamilton, which has 777 beds and three campuses. This healthcare group provides inpatient and outpatient services, and mental illness or addiction help.

Sister cities
The City of Hamilton is twinned with ten sister cities:

 * 🇨🇦 Shawinigan, Quebec, Canada (1958)
 * 🇯🇵 Kaga, Ishikawa, Japan (1968)
 * Sister City agreement originally with Dundas, Ontario.
 * Converted to sister city agreement with the City of Hamilton following Dundas's amalgamation into Hamilton.
 * 🇮🇳 Mangalore, Karnataka, India (1968)
 * 🇯🇵 Fukuyama, Hiroshima, Japan (1975)
 * 🇮🇹 Racalmuto, Sicily, Italy (1987)
 * 🇨🇳 Ma'Anshan, Anhui, China (1987)
 * 🇺🇸 Flint, Michigan, United States (1987)
 * 🇺🇸 Sarasota, Florida, United States (1991)
 * 🇮🇹 Valle Peligna, Abruzzo, Italy (1991)
 * 🇲🇽 Monterrey, Nuevo León, Mexico (1993)

title: Hamilton, Ontario


text:
Talk:Homo (disambiguation)

Links
Latin (language) redirects to Latin, so might as well use the Latin link

Homo (genus) links to an article that mentions 7 'homo' species, not only Homo sapiens sapiens and Homo neanderthalensis. Just follow the link and read all about them. In this disamb page it is irrelevant to name only the two. Also, the link Neanderthal strangely leads to an article about the Homo neanderthalensis, not to an article about the Neanderthal (valley of the Neander river) in Germany, while the link Homo neanderthalensis redirects to the same Neanderthal article - this is very confusing.

HomO
You think that's confusing, take a look at the spelling HomO, that I just added. This is not a joke (though I think it's kind of funny, and so did the Swedish media). Please follow the external link I provided, if you don't believe me. I've never edited a disambiguation page before, so please excuse me if anything's inappropriate. I'm thinking of doing a short article on HomO for this page to link to, and then the text here can be a lot shorter.Bishonen 18:02, 9 Aug 2004 (UTC)

 * I think you did just fine. It would be a good idea to create an article for it, though, then reduce the text in the disambig. - UtherSRG 18:20, 9 Aug 2004 (UTC)

 * Yeah, "Homo" means mainly homosexual, in swedish, as well in english. That HomO example is quite funny!

 * Thanks, UtherSRG. Done. :-) Bishonen 22:02, 9 Aug 2004 (UTC)

Editprotected
I just want to add that its offensive in Canada, too; likely, its offensive else where but I just live in Canada....so.

Thanks

68.148.165.213 19:14, 24 July 2006 (UTC)

 * Already done. —Ruud 19:35, 24 July 2006 (UTC)

As already mentioned above, homo- is derived from the Greek word homos = same, and is used for various words, not just homosexual. So I think homo- should be added as one of possible meanings on this disambiguation page, but obviously I can't do it.

Heimdall 13:10, 26 May 2009 (UTC) —Preceding unsigned comment added by Heimdall1973 (talk • contribs)

Move discussion in progress
There is a move discussion in progress on Talk:Homo (genus) which affects this page. Please participate on that page and not in this talk page section. Thank you. —RM bot 04:30, 4 February 2010 (UTC)

abbreviation for homosexual
whether any term for "homosexual" is "offensive" or "pejorative" is to be discussed at Terminology of homosexuality. That article even manages to allege that the objective, technical "homosexual" is "offensive". Apparently, the only way not to cause offense is not to refer to the concept at all.

The point is that homosexuality (the thing, not the term) is itself negatively charged in mainstream opinion. If you think something is bad, any term referring to that thing will become "a pejorative", no matter what term you use. The de-valuing is in the concept, not in the term you pick. If you do not think that homosexuality is in any way negatively charged, then the term "homosexual" or its abbreviation "homo" won't be either.

Fwiiw, the OED neutrally defines homo as a "colloquial abbreviation" of "homosexual". --dab (𒁳) 13:49, 16 March 2010 (UTC)

 * I'll add a references section if necessary:
 * American Heritage Dictionary: "Slang: Disparaging and Offensive."
 * Boswell, John (1993). "On the use of the term “homo” as a derogatory epithet"
 * etc.
 * AV3000 (talk) 14:33, 16 March 2010 (UTC)
 * right. You are welcome to take your reference to Terminology of homosexuality. This is an opinion, not a fact. The opinion should by all means be recorded, but in an article, not on a disambiguation page. If you read my comment above, you will realize that I have already granted that every epithet for homosexuals can be used derogatorily. The point is that it can be so used. This is not the same as claiming that it "is" somehow inherently pejorative. --dab (𒁳) 10:55, 17 March 2010 (UTC)
 * Gay refers to the same thing, can be used as a slur, but is not a pejorative. I am not aware of any non-pejorative use of 'homo'.  I can see no justification for treating Homo (disambiguation) any differently from Nigger (disambiguation) or Kike (disambiguation); the approach to such slurs is not consistent throughout the encyclopedia, for example Paki acts as a disambiguation page without being such, while WOP acts as a page for the slur, and links to a disambiguation page in which the slur does not feature.  All of them do seem consistent in referring to a slur as a slur, and none seem to support the contention that slurs be referred to as colloquialisms rather than pejoratives. Mish (talk) 16:34, 17 March 2010 (UTC)

OED is your friend.

--dab (𒁳) 17:15, 17 March 2010 (UTC)
 * Regarding non-pejorative use of "homo": OED has a 1933(!) quote, Round about six, fifteen and twenty are the recognized ‘homo’ ages in women.  This is just colloquial use, there is no indication of a disparaging attitude.
 * regarding my point that every term for "homosexual", even plain "homosexual" itself, will be used pejoratively,
 * gay, this is about as pejorative as it gets, with its own OED entry under 4.e: "slang (chiefly U.S.) (sometimes considered offensive). Foolish, stupid, socially inappropriate or disapproved of; ‘lame’."
 * this boils down to your insisting to note that "homo" is an abbreviation that can be used pejoratively of a term that can itself be used pejoratively. The disparaging attitude is in the term that is being abbreviated, not in the act of abbreviating it.
 * absolutely every term for "homosexual", no matter how politically correct in intent, will be used pejoratively, for exactly the same reasons that every term for "fat" or "mentally disabled" will be, for the simple reason that mainstream western culture considers these things defects. I am not saying that this is "correct", it is just a cultural trait subject to change. If you have a quarrel with western culture for attaching a stigma to homosexuality, overweight or mental disability, go and campaign about it, but don't shoot the messenger (descriptive use dictionaries)
 * as a final point, as "Paki" illustrates, you should keep in mind that English is in effect a macrolanguage. Your judgement may be based on the variety most familiar (perhaps native) to you. This does not permit you to jump to conclusions about "English" in general. "Paki" may be a slur in the UK but a harmless abbreviation in Australia. Very similar things may or may not be true of "homo". The task of figuring this out exactly lies with Terminology of homosexuality, not Talk:Homo (disambiguation).

 * dab, I'm unclear on your point. I can show you dozens of reliable sources that state unambiguously that "homo" is a pejorative or derogatory word:
 * (among others)
 * Is there some reason you object to "homo" being treated differently than "Nigger (disambiguation)" or "Kike (disambiguation)", both of which state the pejorative nature of those terms? -- SatyrTN (talk / contribs) 20:48, 17 March 2010 (UTC)
 * (among others)
 * Is there some reason you object to "homo" being treated differently than "Nigger (disambiguation)" or "Kike (disambiguation)", both of which state the pejorative nature of those terms? -- SatyrTN (talk / contribs) 20:48, 17 March 2010 (UTC)
 * Is there some reason you object to "homo" being treated differently than "Nigger (disambiguation)" or "Kike (disambiguation)", both of which state the pejorative nature of those terms? -- SatyrTN (talk / contribs) 20:48, 17 March 2010 (UTC)

 * Point by point
 * Gay is not a pejorative - the OED, as you say, says it is sometimes considered offensive - but this does not seem to be when used to describe people who are gay.
 * Homo is not pejorative because it is an abbreviation of a pejorative. It is a pejorative when used in its own right, when referring to somebody as a 'homo'.
 * I disagree, I do not find queer offensive. If I call somebody a 'cunt', that does not make 'cunt' a pejorative, as they clearly are not a vagina - but if I call them a 'wanker', it is a slur regardless of whether they masturbate a lot or not.
 * Homosexuality, in western culture, is not a defect, even though some people still might think so - it is now regarded as a normal human sexual variation, legally, medically, and socially this view is pretty widespread now.
 * The Paki usage is precisely my point, and the derogatory use is listed - and that is why the disambiguation of Nigger, Kike, etc. also make clear that these are used in a derogatory way. I note you avoid responding to this specific point, presumably because you prefer to ignore points that invalidate your argument.  I take your silence on this as affirming my point, and hope we can now move on; let us wait 24 hours and then append the appropriate comment to align the page with other similar pages.  If you don't like that, then WP:RfC the page. Mish (talk) 21:03, 17 March 2010 (UTC)

 * Comment. Homo certainly has been used pejoratively and done so in mainstream media and is well documented in this use. How we present that here is debatable but some mention that it's not simple an informal way to refer to gay and lesbian people would seem to make sense. Maybe Homo (slang) needs to be written. -- Banj e  b oi   01:41, 18 March 2010 (UTC)
 * Homo (slang, usually derogatory), and so on. Mish (talk) 01:46, 18 March 2010 (UTC)

So when I say that I find this entire discussion extremely gay, you will not feel that I am complaining about the quality of this discussion? I appreciate Mish's point that when used as a noun, "homo" is almost universally pejorative. So is "a homosexual" when used as a noun. The point is in nominalizing an adjective, i.e. inflating a mere attribute of a person to something that defines that person entirely (as in e.g. moving from "having a crippled leg" to "a cripple"). This has nothing to do with the term "homo" in particular, the crucial bit is the shift from adjective to noun. Banj does not seem to have bothered to read anything I wrote, or they would be aware that I never disputed that "homo" has been used pejoratively, as has every other term for "homosexual". The "informal way to refer to gay and lesbian people" strikes me as rather funny, because it implies that the terms "gay" or "lesbian" are somehow less informal, slang or open to pejorative use than "homo". I also find it interesting to claim "X is not the case in culture Y, even though even though some people still might think so". This smacks of prescriptivism. Might it be that you mean that you think that this should be the case? I have no opinion on what "should" be the case in western culture. I readily admit that homosexuality is a non-issue (that is, its existence a mere matter of fact) in many cultures, but "western culture" taken as a whole does not happen to be among these. Obviously "western culture" has subcultures, and depending on what nook or cranny of western culture you happen to live in, you may not be exposed to this overarching tendency too much.

I propose a compromise solution. Otherwise I am not interested in pursuing this further because Wikipedia has more pressing problems. I made Homo (slang) a section redirect, see this diff. This resolves the issue as far as I am concerned. --dab (𒁳) 10:48, 19 March 2010 (UTC)

 * I think it matters little whether it is used as an adjective or noun. "He's gay" - not pejorative.  "He's a gay" - is pejorative.  "He's a gay man" - is not.  "He's homosexual" - is not.  "He's a homosexual" - is.  "He's a homosexual man" - is not.  However, people refer homosexual not be used to refer to gay because historically it was derived from a medical term used which saw homosexuality as a pathology, which it no longer is.  "Gays" is, BTW.  That car is "gay" - that is pejorative, as it is using the word in a way that implies anything that is crap is "gay".  "He's queer" - can be pejorative, depending on how it is used, not of the person identifies as queer, but is if the speaker uses queer as a pejorative, so "you queer", or just "queer", both tend to be pejorative in a way that "I am queer" is not.  Homo is an abbreviation for homosexual, but it is only ever pejorative.  So "he's a homo", "you homo", or just "homo" are equally pejorative.  There is no distinction between use as an adjective or noun.  "Homo" is used as a taunt or slur in its own right, in a similar way to "poof", and has been so for over fifty years.  Where homosexual applies to men and to women, "homo" is usually reserved for men only.  So, I feel that (noun, adjective) needs to be consistent and retain the brackets, while pejorative need not be bracketed, nor implied that only as a noun is this pejorative.  Some white people still attribute negativity to being a negro in this culture, but it is not that "negro" itself can be seen as derogatory that makes nigger derogatory - nigger is derogatory in its own right.  That is the way it is, and regardless of whether being black is a bad thing or not, that doesn't have anything to do with why nigger is pejorative.  The same applies with homo: some people still attribute negativity to being homosexual in this culture, but it is not that "homosexual" itself can be seen as derogatory that makes homo derogatory - homo is derogatory in its own right.  What I think should be case is not significant, and describing the way things are is not presciptive.  It doesn't matter that large areas in the USA see homosexuality as negative, or that in the dominant culture in the UK this is not an issue, what does matter is how the word is used when it is used.  When it is used it is used pejoratively, and whether that is because homosexuality is perceived negatively or not isn't really relevant to that.  It helps explain why a pejorative might be used, and why this word might have come to be used in that way, but that doesn't really matter - all we are concerned with is whether it is or not.  I appreciate that you consider this too trivial to bother responding to.  I look forward to not seeing any response. Mish (talk) 13:22, 19 March 2010 (UTC)

Homo Milk
Canadians do in fact use the term homo milk, as anyone who has lived in Canada knows. Googling the term "homo milk" in quotes brings up many sites confirming this, such as http://americansguide.ca/isms.html and http://www.torontomike.com/2009/11/homo_milk.html. The dubious tag should therefore be removed from the homo disambiguation page.Porphyry Jones (talk) 06:36, 6 July 2010 (UTC)

 * Yeah, why did someone mark that as dubious? Did they think it was some kind of joke about Canadians? (If so, it's not a very good joke.) I'm removing that tag. 99.227.60.109 (talk) 23:57, 1 August 2010 (UTC)

Text moved here to Talk, from overly long, overly detailed Homo/homolog disambiguation entry
The following text should appear elsewhere; it is too detailed relative to the remaining bullets, and in general (esp. the list of examples):
 * " i.e., one noncyclic carbon more (and similarly "dihomo-" meaning two noncyclic carbons more) – examples include:
 * Dihomo-gamma-linolenic acid
 * Homochlorcyclizine
 * Homovanillic acid"

This information can be moved to the linked main articles. Le Prof Leprof 7272 (talk) 17:46, 20 May 2014 (UTC)

Moving surname entry here, because no linked article exists
Add this back later when article appears:

"* Homo (surname), a French surname originating from Brittany and Normandy, borrowed from church Latin"

Le Prof Leprof 7272 (talk) 18:00, 20 May 2014 (UTC)

Inconsistency across many wikipedia pages even though they have identical roots
The following pages are inconsistent..

Hetero (disambiguation) v.s. this page.

hetero v.s. homo.

On hetero.. "(informal) Heterosexual"

On homo.. "(colloquial, often derogatory) Clipping of homosexual"

On Hetero (disambiguation).. "Heterosexuality, attraction towards the opposite sex"

On this page.. ""Homo (slang), an abbreviation for "homosexual", generally offensive""

It makes no sense that even though both hetero and homo have identical roots, namely they were both coined by Karl-Maria Kertbeny in 1868, they are described with such bias. Wikipedia should contain information, not "popular" opinion. Information in this case would be using these words as they were meant in their origin, which would mean the following changes..

.. changing "colloquial" to "informal" on homo

.. removing "often derogatory" on homo

.. changing ""Homo (slang), an Homo (slang), an abbreviation for "homosexual", generally offensive" to "Homosexuality, attraction towards the opposite sex" 31.20.106.40 (talk) 17:33, 12 October 2023 (UTC)

title: Talk:Homo (disambiguation)