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The expansion of the universe according to the Big Bang theory in physics
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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Ursula Martius Franklin CC OOnt FRSC (16 September 1921 – 22 July 2016) was a Canadian metallurgist, research physicist, author, and educator who taught at the University of Toronto for more than 40 years. Franklin is best known for her writings on the political and social effects of technology. She was the author of The Real World of Technology, which is based on her 1989 Massey Lectures; The Ursula Franklin Reader: Pacifism as a Map, a collection of her papers, interviews, and talks; and Ursula Franklin Speaks: Thoughts and Afterthoughts, containing 22 of her speeches and five interviews between 1986 and 2012. Franklin was a practising Quaker and actively worked on behalf of pacifist and feminist causes. She wrote and spoke extensively about the futility of war and the connection between peace and social justice. Franklin received numerous honours and awards, including the Governor General's Award in Commemoration of the Persons Case for promoting the equality of girls and women in Canada and the Pearson Medal of Peace for her work in advancing human rights. In 2012, she was inducted into the Canadian Science and Engineering Hall of Fame. A Toronto high school, Ursula Franklin Academy, as well as Ursula Franklin Street on the University of Toronto campus, have been named in her honor.
For Franklin, technology was much more than machines, gadgets or electronic transmitters. It was a comprehensive system that includes methods, procedures, organization, "and most of all, a mindset". She distinguished between holistic technologies used by craft workers or artisans and prescriptive ones associated with a division of labour in large-scale production. Holistic technologies allow artisans to control their own work from start to finish. Prescriptive technologies organize work as a sequence of steps requiring supervision by bosses or managers. Franklin argued that the dominance of prescriptive technologies in modern society discourages critical thinking and promotes "a culture of compliance". (Full article...)Did you know -
A moonbow over Kihei, Maui, Hawaii, US
- ...that Isaac Newton originally defined force as the rate of change of momentum with respect to time?
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Image credit: Luc Viatour
Plasma lamps are a type of electrodeless gas-discharge lamp energized by radio frequency (RF) power. They are distinct from the novelty plasma lamps that were popular in the 1980s.
The internal-electrodeless lamp was invented by Nikola Tesla after his experimentation with high-frequency currents in evacuated glass tubes for the purposes of lighting and the study of high voltage phenomena. The first practical plasma lamps were the sulfur lamps manufactured by Fusion Lighting. This lamp suffered several practical problems and did not prosper commercially. Plasma lamps with an internal phosphor coating are called external electrode fluorescent lamps (EEFL); these external electrodes or terminal conductors provide the radio frequency electric field. (Full article...)
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The Wright brothers, Orville Wright (August 19, 1871 – January 30, 1948) and Wilbur Wright (April 16, 1867 – May 30, 1912), were American aviation pioneers generally credited with inventing, building, and flying the world's first successful airplane. They made the first controlled, sustained flight of an engine-powered, heavier-than-air aircraft with the Wright Flyer on December 17, 1903, four miles (6 km) south of Kitty Hawk, North Carolina, at what is now known as Kill Devil Hills. In 1904 the Wright brothers developed the Wright Flyer II, which made longer-duration flights including the first circle, followed in 1905 by the first truly practical fixed-wing aircraft, the Wright Flyer III.
The brothers' breakthrough invention was their creation of a three-axis control system, which enabled the pilot to steer the aircraft effectively and to maintain its equilibrium. Their system of aircraft controls made fixed-wing powered flight possible and remains standard on airplanes of all kinds. Their first U.S. patent did not claim invention of a flying machine, but rather a system of aerodynamic control that manipulated a flying machine's surfaces. From the beginning of their aeronautical work, the brothers focused on developing a reliable method of pilot control as the key to solving "the flying problem". This approach differed significantly from other experimenters of the time who put more emphasis on developing powerful engines. Using a small home-built wind tunnel, the Wrights also collected more accurate data than any before, enabling them to design more efficient wings and propellers. (Full article...)
Robert Fox Bacher (August 31, 1905 – November 18, 2004) was an American nuclear physicist and one of the leaders of the Manhattan Project. Born in Loudonville, Ohio, Bacher obtained his undergraduate degree and doctorate from the University of Michigan, writing his 1930 doctoral thesis under the supervision of Samuel Goudsmit on the Zeeman effect of the hyperfine structure of atomic levels. After graduate work at the California Institute of Technology (Caltech) and the Massachusetts Institute of Technology (MIT), he accepted a job at Columbia University. In 1935 he accepted an offer from Hans Bethe to work with him at Cornell University in Ithaca, New York. It was there that Bacher collaborated with Bethe on his book Nuclear Physics. A: Stationary States of Nuclei (1936), the first of three books that would become known as the "Bethe Bible".
In December 1940, Bacher joined the Radiation Laboratory at MIT, although he did not immediately cease his research at Cornell into the neutron cross section of cadmium. The Radiation Laboratory was organized into two sections, one for incoming radar signals, and one for outgoing radar signals. Bacher was appointed to handle the incoming signals section. Here he gained valuable experience in administration, coordinating not just the efforts of his scientists, but also those of General Electric and RCA. In 1942, Bacher was approached by Robert Oppenheimer to join the Manhattan Project at its new laboratory in Los Alamos, New Mexico. It was at Bacher's insistence that Los Alamos became a civilian rather than a military laboratory. At Los Alamos, Bacher headed the project's P (Physics) Division, and later its G (Gadget) Division. Bacher worked closely with Oppenheimer, and the two men discussed the project's progress on a daily basis. (Full article...)
Leo Szilard (/ˈsɪlɑːrd/; Hungarian: Szilárd Leó, pronounced [ˈsilaːrd ˈlɛoː]; born Leó Spitz; February 11, 1898 – May 30, 1964) was a Hungarian-American physicist and inventor. He conceived the nuclear chain reaction in 1933, patented the idea in 1936, and in late 1939 wrote the letter for Albert Einstein's signature that resulted in the Manhattan Project that built the atomic bomb. According to György Marx, he was one of the Hungarian scientists known as The Martians.
Together with Enrico Fermi, he applied for a nuclear reactor patent in 1944. In addition to the nuclear reactor, Szilard coined and submitted the earliest known patent applications and the first publications for the concept of the electron microscope (1928), the cyclotron (1929), and contributed to the development of the linear accelerator (1928) in Germany. Between 1926 and 1930, he worked with Einstein on the development of the Einstein refrigerator. His inventions, discoveries, and contributions related to biological science are also equally important, they include the discovery of feedback inhibition and the invention of the chemostat. According to Theodore Puck and Philip I. Marcus, Szilard gave essential advice which made the earliest cloning of the human cell a reality. (Full article...)
Alvin Cushman Graves (November 4, 1909 – July 28, 1965) was an American nuclear physicist who served at the Manhattan Project's Metallurgical Laboratory and the Los Alamos Laboratory during World War II. After the war, he became the head of the J (Test) Division at Los Alamos and was director or assistant director of numerous nuclear weapons tests during the 1940s and 1950s. Graves was severely injured in the 1946 laboratory criticality accident in Los Alamos that killed Louis Slotin, but recovered. (Full article...)
John Harmen "Jack" Marburger III (February 8, 1941 – July 28, 2011) was an American physicist who directed the Office of Science and Technology Policy in the administration of President George W. Bush, serving as the Science Advisor to the President. His tenure was marred by controversy regarding his defense of the administration against allegations from over two dozen Nobel Laureates, amongst others, that scientific evidence was being suppressed or ignored in policy decisions, including those relating to stem cell research and global warming. However, he has also been credited with keeping the political effects of the September 11 attacks from harming science research—by ensuring that tighter visa controls did not hinder the movement of those engaged in scientific research—and with increasing awareness of the relationship between science and government. He also served as the President of Stony Brook University from 1980 until 1994, and director of Brookhaven National Laboratory from 1998 until 2001. (Full article...).jpg.webp)
Philip Morrison (November 7, 1915 – April 22, 2005) was a professor of physics at the Massachusetts Institute of Technology (MIT). He is known for his work on the Manhattan Project during World War II, and for his later work in quantum physics, nuclear physics high energy astrophysics, and SETI.
A graduate of Carnegie Tech, Morrison became interested in physics, which he studied at the University of California, Berkeley, under the supervision of J. Robert Oppenheimer. He also joined the Communist Party. During World War II he joined the Manhattan Project's Metallurgical Laboratory at the University of Chicago, where he worked with Eugene Wigner on the design of nuclear reactors. (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 joined the Manhattan Project, the World War II efforts to develop nuclear weapons 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. The enriched uranium was used to make the "Little Boy" atomic bomb for the Hiroshima nuclear bombing on August 6, 1945. (Full article...)
PSR B1937+21 is a pulsar located in the constellation Vulpecula a few degrees in the sky away from the first discovered pulsar, PSR B1919+21. The name PSR B1937+21 is derived from the word "pulsar" and the declination and right ascension at which it is located, with the "B" indicating that the coordinates are for the 1950.0 epoch. PSR B1937+21 was discovered in 1982 by Don Backer, Shri Kulkarni, Carl Heiles, Michael Davis, and Miller Goss.
It is the first discovered millisecond pulsar, with a rotational period of 1.557708 milliseconds, meaning it completes almost 642 rotations per second. This period was far shorter than astronomers considered pulsars capable of reaching, and led to the suggestion that pulsars can be spun-up by accreting mass from a companion. (Full article...)
Chien-Shiung Wu (Chinese: 吳健雄; pinyin: Wú Jiànxióng; Wade–Giles: Wu2 Chien4-hsiung2; May 31, 1912 – February 16, 1997) was a Chinese-American particle and experimental physicist who made significant contributions in the fields of nuclear and particle physics. Wu worked on the Manhattan Project, where she helped develop the process for separating uranium into uranium-235 and uranium-238 isotopes by gaseous diffusion. She is best known for conducting the Wu experiment, which proved that parity is not conserved. This discovery resulted in her colleagues Tsung-Dao Lee and Chen-Ning Yang winning the 1957 Nobel Prize in Physics, while Wu herself was awarded the inaugural Wolf Prize in Physics in 1978. Her expertise in experimental physics evoked comparisons to Marie Curie. Her nicknames include the "First Lady of Physics", the "Chinese Madame Curie" and the "Queen of Nuclear Research". (Full article...)
George Thomas Reynolds (May 27, 1917 – April 19, 2005) was an American physicist best known for his accomplishments in particle physics, biophysics and environmental science.
Reynolds received his PhD in physics from Princeton in 1943, writing a thesis of the propagation of shock waves. During World War II, he joined the United States Navy, and served with the Manhattan Project. He worked with George Kistiakowsky on the design of the explosive lenses required by the implosion-type nuclear weapon. He was involved in the investigation of the Port Chicago disaster, served with Project Alberta on Tinian, and was part of the Manhattan Project team sent to Hiroshima and Nagasaki to inspect the bomb damage. (Full article...)
Leo James Rainwater (December 9, 1917 – May 31, 1986) was an American physicist who shared the Nobel Prize in Physics in 1975 for his part in determining the asymmetrical shapes of certain atomic nuclei.
During World War II, he worked on the Manhattan Project that developed the first atomic bombs. In 1949, he began developing his theory that, contrary to what was then believed, not all atomic nuclei are spherical. His ideas were later tested and confirmed by Aage Bohr's and Ben Mottelson's experiments. He also contributed to the scientific understanding of X-rays and participated in the United States Atomic Energy Commission and naval research projects. (Full article...)
Walter Henry Zinn (December 10, 1906 – February 14, 2000) was a Canadian-born American nuclear physicist who was the first director of the Argonne National Laboratory from 1946 to 1956. He worked at the Manhattan Project's Metallurgical Laboratory during World War II, and supervised the construction of Chicago Pile-1, the world's first nuclear reactor, which went critical on December 2, 1942, at the University of Chicago. At Argonne he designed and built several new reactors, including Experimental Breeder Reactor I, the first nuclear reactor to produce electric power, which went live on December 20, 1951. (Full article...)
The Avogadro constant, commonly denoted NA or L, is an SI defining constant with an exact value of 6.02214076×1023 mol-1 (reciprocal moles). It is defined as the number of constituent particles (usually molecules, atoms, or ions) per mole (SI unit) and used as a normalization factor in the amount of substance in a sample. In practice, its value is often approximated as 6.02×1023 mol-1 or 6.022×1023 mol-1. The constant is named after the physicist and chemist Amedeo Avogadro (1776–1856).
The Avogadro constant NA is also the factor that converts the average mass of one particle, in grams, to the molar mass of the substance, in grams per mole (g/mol). (Full article...)
Hugh Bradner (November 5, 1915 – May 5, 2008) was an American physicist at the University of California who is credited with inventing the neoprene wetsuit, which helped to revolutionize scuba diving and surfing.
A graduate of Ohio's Miami University, he received his doctorate from California Institute of Technology in Pasadena, California, in 1941. He worked at the US Naval Ordnance Laboratory during World War II, where he researched naval mines. In 1943, he was recruited by Robert Oppenheimer to join the Manhattan Project at the Los Alamos Laboratory. There, he worked with scientists including Luis Alvarez, John von Neumann and George Kistiakowsky on the development of the high explosives and exploding-bridgewire detonators required by atomic bombs. (Full article...)- Electrical elastance is the reciprocal of capacitance. The SI unit of elastance is the inverse farad (F−1). The concept is not widely used by electrical and electronic engineers. The value of capacitors is invariably specified in units of capacitance rather than inverse capacitance. However, it is used in theoretical work in network analysis and has some niche applications at microwave frequencies.
The term elastance was coined by Oliver Heaviside through the analogy of a capacitor as a spring. The term is also used for analogous quantities in some other energy domains. It maps to stiffness in the mechanical domain, and is the inverse of compliance in the fluid flow domain, especially in physiology. It is also the name of the generalised quantity in bond-graph analysis and other schemes analysing systems across multiple domains. (Full article...)
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January anniversaries
1 January
- 1894 - Satyendra Nath Bose's birthday.
- 1801 - Giuseppe Piazzi is the first to notice the dwarf planet Ceres. However, very soon astronomers lose sight of its orbital path. After some months, Giuseppe Piazzi finally calculates its correct position on December 31.
- 1985 - Ernie Wise, a comedian, places the first mobile phone call in the UK.
2 January
- 2 January 1822 - Rudolf Clausius was born.
4 January
- 4 January 1643 - Sir Issac Newton was born
8 January
- 8 January 1942 - Stephen Hawking was born, on the same day that Galileo Galilei died in 1642.
15 January
- 15 January 1908 - Edward Teller was born.
General images
The following are images from various physics-related articles on Wikipedia.
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)
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)
_in_1958.jpg.webp)
Chien-Shiung Wu worked on parity violation in 1956 and announced her results in January 1957. (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)
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)-Portrait-Portr_10971.tif_(cropped).jpg.webp)
Sir Isaac Newton
(1642–1727) (from History of physics)
The Standard Model. (from History of 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)
William Thomson (Lord Kelvin)
(1824–1907) (from History of physics)
Albert Einstein (1879–1955), photographed here in around 1905 (from History of physics)
Christiaan Huygens
(1629–1695) (from History of physics)
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)
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)
Galileo Galilei, early proponent of the modern scientific worldview and method
(1564–1642) (from History of 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)
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)
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)
Richard Feynman's Los Alamos ID badge (from History of physics)
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)
Marie Skłodowska-Curie
(1867–1934) She was awarded two Nobel prizes, Physics (1903) and Chemistry (1911) (from History of physics)
Heike Kamerlingh Onnes and Johannes van der Waals with the helium liquefactor at Leiden in 1908 (from Condensed matter physics)
The quantum Hall effect: Components of the Hall resistivity as a function of the external magnetic field (from Condensed matter physics)
The Polish astronomer Nicolaus Copernicus (1473–1543) is remembered for his development of a heliocentric model of the Solar System. (from History of physics)
The ancient Greek mathematician Archimedes, famous for his ideas regarding fluid mechanics and buoyancy. (from History of physics)
Image of X-ray diffraction pattern from a protein crystal. (from Condensed matter physics)
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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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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