42,772 articles
Discovery of superconductivity
The discovery of superconductivity was the 1911 observation at Leiden, led by Heike Kamerlingh Onnes, that solid mercury's electrical resistance fell to zero when cooled in liquid helium.
Discovery of the electron
The discovery of the electron was J. J. Thomson's 1897 demonstration at the Cavendish Laboratory, Cambridge, that cathode rays are negatively charged particles far lighter than atoms.
Discovery of the Higgs boson
The discovery of the Higgs boson was announced at CERN on 4 July 2012, when the ATLAS and CMS experiments each observed it at a mass of 125 GeV.
Discovery of the neutron
The discovery of the neutron was James Chadwick's 1932 demonstration that the penetrating radiation from bombarded beryllium was a new uncharged particle, the neutron, with a mass close to the proton's.
Discovery of X-rays
The discovery of X-rays was made by German physicist Wilhelm Röntgen at the University of Würzburg on 8 November 1895, earning him the first Nobel Prize in Physics.
Discovery Program
The Discovery Program is a NASA planetary science program, created in 1992, funding competitively selected, principal-investigator-led missions like Pathfinder, Kepler, and InSight under a fixed cost cap.
Discrepancy theory
Discrepancy theory, also known as the theory of irregularities of distribution, is a branch of mathematics studying how evenly discrete objects can approximate balanced distributions, with roots in Hermann Weyl's work.
Discrete and causal approaches to quantum gravity
Discrete and causal approaches to quantum gravity are research programs replacing smooth spacetime with discrete, causally ordered structures, chiefly causal set theory and causal dynamical triangulations.
Discrete dipole approximation
The discrete dipole approximation (DDA), also called the coupled dipole method, is a numerical method in computational electromagnetics that computes how particles of arbitrary shape scatter and absorb light.
Discrete exterior calculus
Discrete exterior calculus, introduced in Anil Hirani's 2003 Caltech dissertation, translates differential forms and the exterior derivative onto simplicial meshes, with applications in computer graphics and electromagnetics.
Discrete Fourier transform
The discrete Fourier transform (DFT) is the form of Fourier analysis computed by computers, converting N samples into complex numbers giving the amplitude and phase of component sinusoids.
Discrete fracture network model
A discrete fracture network (DFN) model simulates fluid flow and transport through fractured rock by representing each fracture explicitly, used in nuclear waste safety and hydraulic fracturing.
Discrete fracture network modeling
Discrete fracture network (DFN) modeling is a geological simulation method representing fractured rock as explicit networks of individual fractures to predict fluid flow and solute transport.
Discrete geometry
Discrete geometry, also called combinatorial geometry, is the branch of geometry studying discrete arrangements of points, lines, polygons, and polyhedra, with applications in robotics, computer graphics, and crystallography.
Discrete Laplace operator
The discrete Laplace operator is a linear operator, usually a matrix, that plays the role of the Laplacian on graphs and grids, encoding connectivity and approximating partial differential equations.
Discrete logarithm
The discrete logarithm is the exponent x satisfying g^x = h in a finite group; recovering it from g and h secures the 1976 Diffie-Hellman key exchange.
Discrete mathematics
Discrete mathematics is the branch of mathematics studying objects with distinct, separated values rather than smoothly varying ones, centered on combinatorics, graph theory, logic, and the mathematical foundations of computing.
Discrete Mathematics (journal)
Discrete Mathematics is a peer-reviewed mathematics journal published by Elsevier that covers combinatorics and graph theory; it was founded in 1971 by North-Holland in Amsterdam.
Discrete space
A discrete space is a set equipped with the discrete topology, the finest topology possible, in which every subset of the set is open and every point is isolated.
Discrete spectrum (functional analysis)
The discrete spectrum of a self-adjoint operator is the part of its spectrum made of isolated eigenvalues of finite multiplicity, with the rest the essential spectrum.
Discrete time and continuous time
Discrete time and continuous time, also called discrete-time and continuous-time variables, are the two ways a system's state can be indexed in time, by difference or differential equations.
Discrete uniform distribution
The discrete uniform distribution is a probability distribution giving equal probability to each of a finite set of equally likely outcomes, such as a fair die roll.
Discrete valuation ring
A discrete valuation ring (DVR) is a principal ideal domain with exactly one nonzero prime ideal; examples include the power series ring k[[t]] and the integers localized at a prime.
Discrete wavelet transform
The discrete wavelet transform (DWT) is a linear transform that decomposes a discrete signal into wavelet coefficients carrying both scale and position information, computed by a fast filter-bank algorithm.
Discretization
Discretization, also called discretizing, replaces a continuous mathematical problem with a finite discrete counterpart a computer can solve, turning differential equations into algebraic systems and signals into samples.
Discriminant
The discriminant is a quantity computed from the coefficients of a polynomial or quadratic form that vanishes exactly when the object degenerates, as when two roots coincide.
Discriminant analysis
Discriminant analysis is a family of supervised statistical classification methods that model differences between known groups and assign new observations to the group they most likely belong to.
Disdrometer
A disdrometer, also called a distrometer, is an instrument that measures the drop size distribution and fall velocity of precipitation particles reaching the ground, used to calibrate weather radar.
Disdyakis triacontahedron
The disdyakis triacontahedron, also called the hexakis icosahedron, is a Catalan solid with 120 scalene triangular faces, the most of any Catalan solid, and serves as the shape of the 120-sided die.
Disease mapping
Disease mapping is the set of statistical methods for estimating and displaying how disease risk varies across small geographic areas, typically by smoothing unstable local rates.