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Physics is the natural science of matter, involving the study of matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. Physics is one of the most fundamental scientific disciplines, with its main goal being to understand how the universe behaves. A scientist who specializes in the field of physics is called a physicist.
Physics is one of the oldest academic disciplines and, through its inclusion of astronomy, perhaps the oldest. Over much of the past two millennia, physics, chemistry, biology, and certain branches of mathematics were a part of natural philosophy, but during the Scientific Revolution in the 17th century these natural sciences emerged as unique research endeavors in their own right. Physics intersects with many interdisciplinary areas of research, such as biophysics and quantum chemistry, and the boundaries of physics are not rigidly defined. New ideas in physics often explain the fundamental mechanisms studied by other sciences and suggest new avenues of research in these and other academic disciplines such as mathematics and philosophy.
Advances in physics often enable new technologies. For example, advances in the understanding of electromagnetism, solid-state physics, and nuclear physics led directly to the development of new products that have dramatically transformed modern-day society, such as television, computers, domestic appliances, and nuclear weapons; advances in thermodynamics led to the development of industrialization; and advances in mechanics inspired the development of calculus. (Full article...)
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Josiah Willard Gibbs (/ɡɪbz/; February 11, 1839 – April 28, 1903) was an American scientist who made significant theoretical contributions to physics, chemistry, and mathematics. His work on the applications of thermodynamics was instrumental in transforming physical chemistry into a rigorous deductive science. Together with James Clerk Maxwell and Ludwig Boltzmann, he created statistical mechanics (a term that he coined), explaining the laws of thermodynamics as consequences of the statistical properties of ensembles of the possible states of a physical system composed of many particles. Gibbs also worked on the application of Maxwell's equations to problems in physical optics. As a mathematician, he created modern vector calculus (independently of the British scientist Oliver Heaviside, who carried out similar work during the same period) and described the Gibbs phenomenon in the theory of Fourier analysis.
In 1863, Yale University awarded Gibbs the first American doctorate in engineering. After a three-year sojourn in Europe, Gibbs spent the rest of his career at Yale, where he was a professor of mathematical physics from 1871 until his death in 1903. Working in relative isolation, he became the earliest theoretical scientist in the United States to earn an international reputation and was praised by Albert Einstein as "the greatest mind in American history." In 1901, Gibbs received what was then considered the highest honor awarded by the international scientific community, the Copley Medal of the Royal Society of London, "for his contributions to mathematical physics." (Full article...)Did you know -
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- ...that while Albert Einstein is most famous for his Theory of Relativity, he was awarded the Nobel Prize for his explanation of the photoelectric effect?
- ...that gravitational tidal accelerations are the result of the curvature of spacetime?
- ...that the blue glow of the Cherenkov effect is due to electrons moving faster than the speed of light in water?
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A ferrofluid on a glass plate, being affected by a rare-earth magnet
Image credit: Gregory Maxwell
A ferrofluid is a liquid which becomes strongly polarised in the presence of a magnetic field. Ferrofluids are composed of nanoscale ferromagnetic particles suspended in a carrier fluid, usually an organic solvent or water. The ferromagnetic nano-particles are coated with a surfactant to prevent their agglomeration (due to van der Waals and magnetic forces). Although the name may suggest otherwise, ferrofluids do not display ferromagnetism, since they do not retain magnetisation in the absence of an externally applied field. In fact, ferrofluids display paramagnetism, and are often referred as being "superparamagnetic" due to their large magnetic susceptibility. True ferromagnetic fluids are difficult to create at present.
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These are Good articles, which meet a core set of high editorial standards.
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Chanda Prescod-Weinstein (born c. 1982) is an American theoretical cosmologist and particle physicist at the University of New Hampshire. She is also an advocate of increasing diversity in science. (Full article...) -
The state of a vibrating string can be modeled as a point in a Hilbert space. The decomposition of a vibrating string into its vibrations in distinct overtones is given by the projection of the point onto the coordinate axes in the space.
In mathematics, Hilbert spaces (named after David Hilbert) allow the methods of linear algebra and calculus to be generalized from (finite-dimensional) Euclidean vector spaces to spaces that may be infinite-dimensional. Hilbert spaces arise naturally and frequently in mathematics and physics, typically as function spaces. Formally, a Hilbert space is a vector space equipped with an inner product that induces a distance function for which the space is a complete metric space.
The earliest Hilbert spaces were studied from this point of view in the first decade of the 20th century by David Hilbert, Erhard Schmidt, and Frigyes Riesz. They are indispensable tools in the theories of partial differential equations, quantum mechanics, Fourier analysis (which includes applications to signal processing and heat transfer), and ergodic theory (which forms the mathematical underpinning of thermodynamics). John von Neumann coined the term Hilbert space for the abstract concept that underlies many of these diverse applications. The success of Hilbert space methods ushered in a very fruitful era for functional analysis. Apart from the classical Euclidean vector spaces, examples of Hilbert spaces include spaces of square-integrable functions, spaces of sequences, Sobolev spaces consisting of generalized functions, and Hardy spaces of holomorphic functions. (Full article...) -
Christiaan Huygens, Lord of Zeelhem, FRS (/ˈhaɪɡənz/ HY-gənz, US: /ˈhɔɪɡənz/ HOY-gənz, Dutch: [ˈkrɪstijaːn ˈɦœyɣə(n)s] ; also spelled Huyghens; Latin: Hugenius; 14 April 1629 – 8 July 1695) was a Dutch mathematician, physicist, engineer, astronomer, and inventor who is regarded as a key figure in the Scientific Revolution. In physics, Huygens made seminal contributions to optics and mechanics, while as an astronomer he studied the rings of Saturn and discovered its largest moon, Titan. As an engineer and inventor, he improved the design of telescopes and invented the pendulum clock, the most accurate timekeeper for almost 300 years. A talented mathematician and physicist, his works contain the first idealization of a physical problem by a set of mathematical parameters, and the first mathematical and mechanistic explanation of an unobservable physical phenomenon.
Huygens first identified the correct laws of elastic collision in his work De Motu Corporum ex Percussione, completed in 1656 but published posthumously in 1703. In 1659, Huygens derived geometrically the formula in classical mechanics for the centrifugal force in his work De vi Centrifuga, a decade before Newton. In optics, he is best known for his wave theory of light, which he described in his Traité de la Lumière (1690). His theory of light was initially rejected in favour of Newton's corpuscular theory of light, until Augustin-Jean Fresnel adapted Huygens's principle to give a complete explanation of the rectilinear propagation and diffraction effects of light in 1821. Today this principle is known as the Huygens–Fresnel principle. (Full article...) -
William George Penney, Baron Penney, OM, KBE, FRS, FRSE (24 June 1909 – 3 March 1991) was an English mathematician and professor of mathematical physics at the Imperial College London and later the rector of Imperial College London. He had a leading role in the development of High Explosive Research, Britain's clandestine nuclear programme that started in 1942 during the Second World War which produced the first British atomic bomb in 1952.
As the head of the British delegation working on the Manhattan Project at Los Alamos Laboratory, Penney initially carried out calculations to predict the damage effects generated by the blast wave of an atomic bomb. Upon returning home, Penney directed the British nuclear weapons directorate, codenamed Tube Alloys and directed scientific research at the Atomic Weapons Research Establishment which resulted in the first detonation of a British nuclear bomb in Operation Hurricane in 1952. After the test, Penney became chief advisor to the new United Kingdom Atomic Energy Authority (UKAEA). He was later chairman of the authority, which he used in international negotiations to control nuclear testing with the Partial Nuclear Test Ban Treaty. (Full article...) -
In 1850, Léon Foucault used a rotating mirror to perform a differential measurement of the speed of light in water versus its speed in air. In 1862, he used a similar apparatus to measure the speed of light in the air. (Full article...)
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A waterspout near Florida in 1969. Two flares with smoke trails (near base of photograph) have been discharged to indicate wind direction and general speed.
A waterspout is a rotating column of air that occurs over a body of water, usually appearing as a funnel-shaped cloud in contact with the water and a cumuliform cloud. There are two types of waterspout, each formed by distinct mechanisms. The most common type is a weak vortex known as a "fair weather" or "non-tornadic" waterspout. The other less common type is simply a classic tornado occurring over water rather than land, known as a "tornadic", "supercellular", or "mesocyclonic" waterspout, and accurately a "tornado over water". A fair weather waterspout has a five-part life cycle: formation of a dark spot on the water surface; spiral pattern on the water surface; formation of a spray ring; development of a visible condensation funnel; and ultimately, decay. Most waterspouts do not suck up water.
While waterspouts form mostly in tropical and subtropical areas, they are also reported in Europe, Western Asia (the Middle East), Australia, New Zealand, the Great Lakes, Antarctica, and on rare occasions, the Great Salt Lake. Some are also found on the East Coast of the United States, and the coast of California. Although rare, waterspouts have been observed in connection with lake-effect snow precipitation bands. (Full article...) -
Geocentric celestial spheres; Peter Apian's Cosmographia (Antwerp, 1539)
The celestial spheres, or celestial orbs, were the fundamental entities of the cosmological models developed by Plato, Eudoxus, Aristotle, Ptolemy, Copernicus, and others. In these celestial models, the apparent motions of the fixed stars and planets are accounted for by treating them as embedded in rotating spheres made of an aetherial, transparent fifth element (quintessence), like gems set in orbs. Since it was believed that the fixed stars did not change their positions relative to one another, it was argued that they must be on the surface of a single starry sphere.
In modern thought, the orbits of the planets are viewed as the paths of those planets through mostly empty space. Ancient and medieval thinkers, however, considered the celestial orbs to be thick spheres of rarefied matter nested one within the other, each one in complete contact with the sphere above it and the sphere below. When scholars applied Ptolemy's epicycles, they presumed that each planetary sphere was exactly thick enough to accommodate them. By combining this nested sphere model with astronomical observations, scholars calculated what became generally accepted values at the time for the distances to the Sun: about 4 million miles (6.4 million kilometres), to the other planets, and to the edge of the universe: about 73 million miles (117 million kilometres). The nested sphere model's distances to the Sun and planets differ significantly from modern measurements of the distances, and the size of the universe is now known to be inconceivably large and continuously expanding. (Full article...) -
Adriana C. Ocampo Uria (born January 5, 1955) is a Colombian planetary geologist and a Science Program Manager at NASA Headquarters. In 1970, Ocampo emigrated to California and completed her Master in Sciences at California State University, Northridge and finished her PhD at the Vrije Universiteit in the Netherlands. During high school and graduate studies she worked at the Jet Propulsion Laboratory, where she serves as the science coordinator for many planetary missions (Viking, Mars Observer, Voyager, Galileo Galileo Mission, etc).
She was the first to recognize, using satellite images, that a ring of cenotes or sinkholes, is the only surface impression of the buried Chicxulub crater. This research contributed significantly to the understanding of this impact crater. Ocampo has subsequently led at least seven research expeditions to the Chicxulub site. and to Belize K/Pg ejecta sites, which she discovered and are the subject of her MSc and PhD. She continues to search for new impact craters, and with her team, in 2017, reported on a possible crater near Cali, Colombia. (Full article...) -
In physics, a force is an influence that can cause an object to change its velocity, i.e., to accelerate, meaning a change in speed or direction, unless counterbalanced by other forces. The concept of force makes the everyday notion of pushing or pulling mathematically precise. Because the magnitude and direction of a force are both important, force is a vector quantity. The SI unit of force is the newton (N), and force is often represented by the symbol F.
Force plays a central role in classical mechanics, figuring in all three of Newton's laws of motion, which specify that the force on an object with an unchanging mass is equal to the product of the object's mass and the acceleration that it undergoes.
Types of forces often encountered in classical mechanics include elastic, frictional, contact or "normal" forces, and gravitational. The rotational version of force is torque, which produces changes in the rotational speed of an object. In an extended body, each part often applies forces on the adjacent parts; the distribution of such forces through the body is the internal mechanical stress. In equilibrium these stresses cause no acceleration of the body as the forces balance one another. If these are not in equilibrium they can cause deformation of solid materials, or flow in fluids. (Full article...) -
The Wow! signal represented as "6EQUJ5". The original printout with Ehman's handwritten exclamation is preserved by Ohio History Connection.
The Wow! signal was a strong narrowband radio signal detected on August 15, 1977, by Ohio State University's Big Ear radio telescope in the United States, then used to support the search for extraterrestrial intelligence. The signal appeared to come from the direction of the constellation Sagittarius and bore expected hallmarks of extraterrestrial origin.
Astronomer Jerry R. Ehman discovered the anomaly a few days later while reviewing the recorded data. He was so impressed by the result that he circled on the computer printout the reading of the signal's intensity, "6EQUJ5", and wrote the comment "Wow!" beside it, leading to the event's widely used name. (Full article...) -
The Nobel Prize in Physics (Swedish: Nobelpriset i fysik) is an annual award given by the Royal Swedish Academy of Sciences for those who have made the most outstanding contributions to mankind in the field of physics. It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895 and awarded since 1901, the others being the Nobel Prize in Chemistry, Nobel Prize in Literature, Nobel Peace Prize, and Nobel Prize in Physiology or Medicine. Physics is traditionally the first award presented in the Nobel Prize ceremony.
The prize consists of a medal along with a diploma and a certificate for the monetary award. The front side of the medal displays the same profile of Alfred Nobel depicted on the medals for Physics, Chemistry, and Literature. (Full article...) -
Mary Jackson (née Winston; April 9, 1921 – February 11, 2005) was an American mathematician and aerospace engineer at the National Advisory Committee for Aeronautics (NACA), which in 1958 was succeeded by the National Aeronautics and Space Administration (NASA). She worked at Langley Research Center in Hampton, Virginia, for most of her career. She started as a computer at the segregated West Area Computing division in 1951. In 1958, after taking engineering classes, she became NASA's first black female engineer.
After 34 years at NASA, Jackson had earned the most senior engineering title available. She realized she could not earn further promotions without becoming a supervisor. She accepted a demotion to become a manager of both the Federal Women's Program, in the NASA Office of Equal Opportunity Programs and of the Affirmative Action Program. In this role, she worked to influence the hiring and promotion of women in NASA's science, engineering, and mathematics careers. (Full article...) -
Elda Emma Anderson (October 5, 1899 – April 17, 1961) was an American physicist and health researcher. During World War II, she worked on the Manhattan Project at Princeton University and the Los Alamos National Laboratory, where she prepared the first sample of pure uranium-235 at the laboratory. A graduate of the University of Wisconsin, she became professor of physics at Milwaukee-Downer College in 1929. After the war, she became interested in health physics. She worked in the Health Physics Division of the Oak Ridge National Laboratory, and established the professional certification agency known as the American Board of Health Physics. (Full article...) -
Calutron Girls photographed by Ed Westcott at their calutron control panels at Y-12
The Calutron Girls were a group of young women—mostly high school graduates—who had joined the Manhattan Project at the Y-12 National Security Complex located at Oak Ridge, Tennessee, from 1943 to 1945. Although they were not allowed to know at the time, they were monitoring dials and watching meters for calutrons, mass spectrometers adapted for separation of uranium isotopes for the development of nuclear weapons for use during World War II. The enriched uranium was used to make the "Little Boy" atomic bomb for the Hiroshima nuclear bombing on August 6, 1945. (Full article...) -
Deep Impact was a NASA space probe launched from Cape Canaveral Air Force Station on January 12, 2005. It was designed to study the interior composition of the comet Tempel 1 (9P/Tempel), by releasing an impactor into the comet. At 05:52 UTC on July 4, 2005, the Impactor successfully collided with the comet's nucleus. The impact excavated debris from the interior of the nucleus, forming an impact crater. Photographs taken by the spacecraft showed the comet to be more dusty and less icy than had been expected. The impact generated an unexpectedly large and bright dust cloud, obscuring the view of the impact crater.
Previous space missions to comets, such as Giotto, Deep Space 1, and Stardust, were fly-by missions. These missions were able to photograph and examine only the surfaces of cometary nuclei, and even then from considerable distances. The Deep Impact mission was the first to eject material from a comet's surface, and the mission garnered considerable publicity from the media, international scientists, and amateur astronomers alike. (Full article...)
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June anniversaries
- 1 June 1831 – James Clark Ross discovers the North Magnetic Pole.
- 1 June 1869 – Thomas Edison receives a patent for his electric voting machine.
- 1 June 1910 – Robert Falcon Scott expedition leaves England for South Pole.
- 1 June 1978 – First Patent Cooperation Treaty international filings.
- 1 June 1980 – Cable News Network (CNN) begins broadcasting.
- 1 June 1990 – Bush and Gorbachev sign chemical weapons ban.
- 1 June 2000 – Patent Law Treaty is signed.
- 2 June 1966 – Surveyor 1 lands on the Moon.
- 2 June 2003 - ESA launches Mars Express probe to Mars.
- 3 June 1965 - First American spacewalk, mission Gemini IV
- 3 June 1973 – A Soviet supersonic Tupolev Tu-144 crashes.
- 4 June 781 BC – First historic solar eclipse is recorded in China.
- 4 June 1973 – A patent for the ATM is granted.
- 4 June 1996 - First flight. Ariane 5 rocket explodes after roughly 20 seconds.
- 5 June 1977 – Apple II, personal computer goes on sale.
Birthdays
- 1 June 1633 – Geminiano Montanari, Italian astronomer (d. 1687)
- 1 June 1796 – Nicolas Léonard Sadi Carnot, French physicist (d. 1832)
- 1 June 1899 – Edward Charles Titchmarsh, English mathematician (d. 1963)
- 1 June 1907 – Frank Whittle, invented jet engine. (d. 1996)
- 1 June 1917 – William S. Knowles Nobel Prize laureate
- 1 June 1940 – Kip Thorne, American physicist
- 2 June 1930 – Pete Conrad, American astronaut (d. 1999)
- 2 June 1949 – Heather Couper, British astronomer
- 3 June 1659 – David Gregory, Scottish astronomer (d. 1708)
- 3 June 1923 – Igor Shafarevich, Russian mathematician
- 4 June 1704 – Benjamin Huntsman, English inventor and manufacturer (d. 1776)
- 4 June 1877 – Heinrich Wieland, German biochemist & Nobel laureate (d. 1957)
- 4 June 1916 – Robert F. Furchgott, American chemist & Nobel laureate (d. 2009)
- 4 June 1967 – Robert Shane Kimbrough, American astronaut
- 5 June 1760 – Johan Gadolin, Finnish scientist (d. 1852)
- 5 June 1819 – John Couch Adams, English astronomer (d. 1892)
- 5 June 1862 – Allvar Gullstrand, Swedish ophthalmologist Nobel laureate (d. 1930)
- 5 June 1900 – Dennis Gabor, Hungarian physicist, Nobel laureate (d. 1979)
- 5 June 1965 – Michael E. Brown, American astronomer
- 13 June 1831 - James Clerk Maxwell, Scottish physicist (d. 1879)
General images
The following are images from various physics-related articles on Wikipedia.
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Classical physics is usually concerned with everyday conditions: speeds are much lower than the speed of light, sizes are much greater than that of atoms, yet very small in astronomical terms. Modern physics, however, is concerned with high velocities, small distances, and very large energies. (from Modern physics) -
One possible signature of a Higgs boson from a simulated proton–proton collision. It decays almost immediately into two jets of hadrons and two electrons, visible as lines. (from History of physics) -
Heike Kamerlingh Onnes and Johannes van der Waals with the helium liquefactor at Leiden in 1908 (from Condensed matter physics) -
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A Feynman diagram representing (left to right) the production of a photon (blue sine wave) from the annihilation of an electron and its complementary antiparticle, the positron. The photon becomes a quark–antiquark pair and a gluon (green spiral) is released. (from History of physics) -
Galileo Galilei, early proponent of the modern scientific worldview and method
(1564–1642) (from History of physics) -
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Albert Einstein (1879–1955), photographed here in around 1905 (from History of physics) -
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Classical physics (Rayleigh–Jeans law, black line) failed to explain black-body radiation – the so-called ultraviolet catastrophe. The quantum description (Planck's law, colored lines) is said to be modern physics. (from Modern physics) -
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Sir Isaac Newton
(1642–1727) (from History of physics) -
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The Hindu-Arabic numeral system. The inscriptions on the edicts of Ashoka (3rd century BCE) display this number system being used by the Imperial Mauryas. (from History of physics) -
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Star maps by the 11th-century Chinese polymath Su Song are the oldest known woodblock-printed star maps to have survived to the present day. This example, dated 1092, employs the cylindrical equirectangular projection. (from History of physics) -
The quantum Hall effect: Components of the Hall resistivity as a function of the external magnetic field (from Condensed matter physics) -
The ancient Greek mathematician Archimedes, developer of ideas regarding fluid mechanics and buoyancy. (from History of physics) -
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Chien-Shiung Wu worked on parity violation in 1956 and announced her results in January 1957. (from History of physics) -
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A magnet levitating above a high-temperature superconductor. Today some physicists are working to understand high-temperature superconductivity using the AdS/CFT correspondence. (from Condensed matter physics) -
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The first Bose–Einstein condensate observed in a gas of ultracold rubidium atoms. The blue and white areas represent higher density. (from Condensed matter physics) -
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The Polish astronomer Nicolaus Copernicus (1473–1543) is remembered for his development of a heliocentric model of the Solar System. (from History of physics) -
William Thomson (Lord Kelvin)
(1824–1907) (from History of physics) -
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Computer simulation of nanogears made of fullerene molecules. It is hoped that advances in nanoscience will lead to machines working on the molecular scale. (from Condensed matter physics) -
Einstein proposed that gravitation is a result of masses (or their equivalent energies) curving ("bending") the spacetime in which they exist, altering the paths they follow within it. (from History of physics) -
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Marie Skłodowska-Curie
(1867–1934) She was awarded two Nobel prizes, Physics (1903) and Chemistry (1911) (from History of physics) -
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The Standard Model. (from History of physics) -
A composite montage comparing Jupiter (lefthand side) and its four Galilean moons (top to bottom: Io, Europa, Ganymede, Callisto). (from History of physics) -
Christiaan Huygens
(1629–1695) (from History of physics) -
Image of X-ray diffraction pattern from a protein crystal (from Condensed matter physics) -
J. J. Thomson (1856–1940) discovered the electron and isotopy and also invented the mass spectrometer. He was awarded the Nobel Prize in Physics in 1906. (from History of physics) -
Richard Feynman's Los Alamos ID badge (from History of physics)
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Categories
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Background: Physicists | History of physics | Philosophy of physics | Physics education | Physics journals | Physics organizations
Other: Physics in fiction | Physics lists | Physics software | Physics stubs
Physics topics
Classical physics traditionally includes the fields of mechanics, optics, electricity, magnetism, acoustics and thermodynamics. The term Modern physics is normally used for fields which rely heavily on quantum theory, including quantum mechanics, atomic physics, nuclear physics, particle physics and condensed matter physics. General and special relativity are usually considered to be part of modern physics as well.
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