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Mass–energy Equivalence
In physics, mass–energy equivalence is the relationship between mass and energy in a system's rest frame. The two differ only by a multiplicative constant and the units of measurement. The principle is described by the physicist Albert Einstein's formula: E = mc^2. In a reference frame where the system is moving, its relativistic energy and relativistic mass (instead of rest mass) obey the same formula. The formula defines the energy () of a particle in its rest frame as the product of mass () with the speed of light squared (). Because the speed of light is a large number in everyday units (approximately ), the formula implies that a small amount of mass corresponds to an enormous amount of energy. Rest mass, also called invariant mass, is a fundamental physical property of matter, independent of velocity. Massless particles such as photons have zero invariant mass, but massless free particles have both momentum and energy. The equivalence principle implies that w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
M87 Jet
M87 or M-87 may refer to: Military * M87 machine gun, a Yugoslav copy of the NSVT machine gun * M-87 Orkan, a Yugoslav rocket-artillery vehicle Transportation * Tumansky M-87, a Soviet aircraft engine * M-87 (Michigan highway), a former state highway in Michigan, US * McDonnell Douglas MD-87, a passenger airplane Other uses * Messier 87, a giant elliptical galaxy in the Virgo Cluster ** Messier 87#Supermassive black hole M87* , M87*, a supermassive black hole at Messier 87's core * M87 Ray (α and β), the signature move of the character Zoffy from the ''Ultra Series'' of television shows; See List of Ultraman Ginga characters#Ultraman Ginga, List of ''Ultraman Ginga'' characters * "M87", the theme song for the 2022 film ''Shin Ultraman'' by Kenshi Yonezu. {{Letter-NumberCombDisambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free Particle
In physics, a free particle is a particle that, in some sense, is not bound by an external force, or equivalently not in a region where its potential energy varies. In classical physics, this means the particle is present in a "field-free" space. In quantum mechanics, it means the particle is in a region of uniform potential, usually set to zero in the region of interest since the potential can be arbitrarily set to zero at any point in space. Classical free particle The classical free particle is characterized by a fixed velocity ''v''. The momentum of a particle with mass ''m'' is given by p=mv and the kinetic energy (equal to total energy) by E=\fracmv^2=\frac. Quantum free particle Mathematical description A free particle with mass m in non-relativistic quantum mechanics is described by the free Schrödinger equation: - \frac \nabla^2 \ \psi(\mathbf, t) = i\hbar\frac \psi (\mathbf, t) where ''ψ'' is the wavefunction of the particle at position r and time ''t''. The sol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spacetime Symmetries
Spacetime symmetries are features of spacetime that can be described as exhibiting some form of symmetry. The role of symmetry in physics is important in simplifying solutions to many problems. Spacetime symmetries are used in the study of exact solutions of Einstein's field equations of general relativity. Spacetime symmetries are distinguished from internal symmetries. Physical motivation Physical problems are often investigated and solved by noticing features which have some form of symmetry. For example, in the Schwarzschild solution, the role of spherical symmetry is important in deriving the Schwarzschild solution and deducing the physical consequences of this symmetry (such as the nonexistence of gravitational radiation in a spherically pulsating star). In cosmological problems, symmetry plays a role in the cosmological principle, which restricts the type of universes that are consistent with large-scale observations (e.g. the Friedmann–Lemaître–Robertson–Walker ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henri Poincaré
Jules Henri Poincaré (, ; ; 29 April 185417 July 1912) was a French mathematician, Theoretical physics, theoretical physicist, engineer, and philosophy of science, philosopher of science. He is often described as a polymath, and in mathematics as "The Last Universalist", since he excelled in all fields of the discipline as it existed during his lifetime. He has further been called "the Carl Friedrich Gauss, Gauss of History of mathematics, modern mathematics". Due to his success in science, along with his influence and philosophy, he has been called "the philosopher par excellence of modern science". As a mathematician and physicist, he made many original fundamental contributions to Pure mathematics, pure and applied mathematics, mathematical physics, and celestial mechanics. In his research on the three-body problem, Poincaré became the first person to discover a chaotic deterministic system which laid the foundations of modern chaos theory. Poincaré is regarded as the cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymath
A polymath or polyhistor is an individual whose knowledge spans many different subjects, known to draw on complex bodies of knowledge to solve specific problems. Polymaths often prefer a specific context in which to explain their knowledge, but some are gifted at explaining abstractly and creatively. Embodying a basic tenet of Renaissance humanism that humans are limitless in their capacity for development, the concept led to the notion that people should embrace all knowledge and develop their capacities as fully as possible. This is expressed in the term Renaissance man, often applied to the Intellectual giftedness, gifted people of that age who sought to develop their abilities in all areas of accomplishment: intellectual, artistic, social, physical, and spiritual. Etymology The word polymath derives from the Ancient Greek, Greek roots ''poly-'', which means "much" or "many," and ''manthanein'', which means "to learn." Plutarch wrote that the Ancient Greek Muses, muse P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paradox
A paradox is a logically self-contradictory statement or a statement that runs contrary to one's expectation. It is a statement that, despite apparently valid reasoning from true or apparently true premises, leads to a seemingly self-contradictory or a logically unacceptable conclusion. A paradox usually involves contradictory-yet-interrelated elements that exist simultaneously and persist over time. They result in "persistent contradiction between interdependent elements" leading to a lasting "unity of opposites". In logic, many paradoxes exist that are known to be invalid arguments, yet are nevertheless valuable in promoting critical thinking, while other paradoxes have revealed errors in definitions that were assumed to be rigorous, and have caused axioms of mathematics and logic to be re-examined. One example is Russell's paradox, which questions whether a "list of all lists that do not contain themselves" would include itself and showed that attempts to found set theory on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Special Relativity
In physics, the special theory of relativity, or special relativity for short, is a scientific theory of the relationship between Spacetime, space and time. In Albert Einstein's 1905 paper, Annus Mirabilis papers#Special relativity, "On the Electrodynamics of Moving Bodies", the theory is presented as being based on just Postulates of special relativity, two postulates: # The laws of physics are Invariant (physics), invariant (identical) in all Inertial frame of reference, inertial frames of reference (that is, Frame of reference, frames of reference with no acceleration). This is known as the principle of relativity. # The speed of light in vacuum is the same for all observers, regardless of the motion of light source or observer. This is known as the principle of light constancy, or the principle of light speed invariance. The first postulate was first formulated by Galileo Galilei (see ''Galilean invariance''). Background Special relativity builds upon important physics ide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Particle Physics
Particle physics or high-energy physics is the study of Elementary particle, fundamental particles and fundamental interaction, forces that constitute matter and radiation. The field also studies combinations of elementary particles up to the scale of protons and neutrons, while the study of combinations of protons and neutrons is called nuclear physics. The fundamental particles in the universe are classified in the Standard Model as fermions (matter particles) and bosons (force-carrying particles). There are three Generation (particle physics), generations of fermions, although ordinary matter is made only from the first fermion generation. The first generation consists of Up quark, up and down quarks which form protons and neutrons, and electrons and electron neutrinos. The three fundamental interactions known to be mediated by bosons are electromagnetism, the weak interaction, and the strong interaction. Quark, Quarks cannot exist on their own but form hadrons. Hadrons that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Physics
Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions, in addition to the study of other forms of nuclear matter. Nuclear physics should not be confused with atomic physics, which studies the atom as a whole, including its electrons. Discoveries in nuclear physics have led to applications in many fields such as nuclear power, nuclear weapons, nuclear medicine and magnetic resonance imaging, industrial and agricultural isotopes, ion implantation in materials engineering, and radiocarbon dating in geology and archaeology. Such applications are studied in the field of nuclear engineering. Particle physics evolved out of nuclear physics and the two fields are typically taught in close association. Nuclear astrophysics, the application of nuclear physics to astrophysics, is crucial in explaining the inner workings of stars and the origin of the chemical elements. History The history of nuclear physics as a discipline ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal Energy
The term "thermal energy" is often used ambiguously in physics and engineering. It can denote several different physical concepts, including: * Internal energy: The energy contained within a body of matter or radiation, excluding the potential energy of the whole system. * Heat: Energy in transfer between a system and its surroundings by mechanisms other than Work (thermodynamics), thermodynamic work and transfer of matter. * The characteristic energy kT (energy), associated with a single microscopic degree of freedom, where denotes temperature and denotes the Boltzmann constant. Mark Zemansky (1970) has argued that the term "thermal energy" is best avoided due to its ambiguity. He suggests using more precise terms such as "internal energy" and "heat" to avoid confusion. The term is, however, used in some textbooks.For example: Relation between heat and internal energy In thermodynamics, heat is energy in transfer to or from a thermodynamic system by mechanisms other than t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light
Light, visible light, or visible radiation is electromagnetic radiation that can be visual perception, perceived by the human eye. Visible light spans the visible spectrum and is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequency, frequencies of 750–420 terahertz (unit), terahertz. The visible band sits adjacent to the infrared (with longer wavelengths and lower frequencies) and the ultraviolet (with shorter wavelengths and higher frequencies), called collectively ''optical radiation''. In physics, the term "light" may refer more broadly to electromagnetic radiation of any wavelength, whether visible or not. In this sense, gamma rays, X-rays, microwaves and radio waves are also light. The primary properties of light are intensity (physics), intensity, propagation direction, frequency or wavelength spectrum, and polarization (waves), polarization. Its speed of light, speed in vacuum, , is one of the fundamental physi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
