All articles starting with G
18,970 articles
Gravitation and Cosmology (book)
Gravitation and Cosmology: Principles and Applications of the General Theory of Relativity is a 1972 graduate textbook by Nobel laureate Steven Weinberg that bases relativity on the principle of equivalence rather than geometry.
Gravitation Jumping Center
Gravitation Jumping Center (Джампінг-центр «Гравітація») is a trampoline park in Lutsk, Ukraine, inside the Adrenalin City complex, with a large trampoline arena, foam pit, and hourly or unlimited tickets.
Gravitation of the Moon
The gravitation of the Moon, or lunar gravity, is the field generated by the Moon's mass, which accelerates surface objects at about one sixth of Earth's rate.
Gravitation water vortex power plant
A gravitation water vortex power plant is a micro hydropower plant where water spiraling in a circular basin drives a turbine, patented by Franz Zotlöterer in 2003.
Gravitational acceleration
Gravitational acceleration, also called acceleration of free fall, is the acceleration of a body under gravity alone, ranging on Earth from 9.78 m/s² at the equator to 9.83 at the poles.
Gravitational anomaly
A gravitational anomaly is a quantum field theory effect in which curved spacetime breaks a chiral conservation law, first observed experimentally in the Weyl semimetal NbP in 2017.
Gravitational behavior of antimatter
Gravitational behavior of antimatter concerns whether it falls or rises in a gravitational field. In 2023, CERN's ALPHA collaboration directly showed antihydrogen atoms fall downward like ordinary matter, excluding antigravity.
Gravitational collapse
Gravitational collapse is the contraction of a region of matter under its own gravity when supporting pressure is insufficient, first analyzed by James Jeans in 1902.
Gravitational constant
The gravitational constant, or Newton's constant, is the constant G in Newton's law of universal gravitation, which fixes the strength of gravity between any two masses anywhere in the universe.
Gravitational decoherence
Gravitational decoherence is the loss of quantum coherence in low-energy quantum systems caused by gravitation, including metric fluctuations and gravity-induced wave function collapse, testable in table-top experiments.
Gravitational energy
Gravitational energy, also known as gravitational potential energy, is the potential energy stored in a system of masses by virtue of their positions in each other's gravitational field.
Gravitational field
A gravitational field is a vector field giving the gravitational force per unit mass at every point in space, equal to the local free-fall acceleration.
Gravitational instability model
The gravitational instability model, also called disk instability, is a planet-formation theory in which giant planets form rapidly from the self-gravity of a young star's gas disk.
Gravitational instanton
A gravitational instanton is a complete, non-singular solution of the Euclidean Einstein equations in four dimensions that approaches flat space at infinity, analogous to Yang–Mills instantons.
Gravitational lens
A gravitational lens, also called a gravity lens, is a massive galaxy or galaxy cluster whose gravity bends light passing near it, distorting and magnifying the image of a distant source behind it.
Gravitational lensing formalism
The gravitational lensing formalism is the set of equations describing how a mass distribution deflects, distorts, magnifies, and delays light, centered on the lens equation and Fermat potential.
Gravitational lensing of the cosmic microwave background
CMB weak lensing is the gravitational distortion of the cosmic microwave background by intervening matter, which traces the universe's projected mass distribution and constrains dark energy and neutrino mass.
Gravitational microlensing
Gravitational microlensing, also called microlensing, is a form of gravitational lensing in which a foreground star briefly magnifies a distant background star's light, producing no resolvable image.
Gravitational path-integral methods
Gravitational path-integral methods quantize general relativity by summing over all spacetime geometries; central issues include the conformal-factor problem, gauge fixing, and whether an asymptotic-safety fixed point exists.
Gravitational potential
Gravitational potential, also called gravity potential, is the gravitational potential energy of a unit test mass at a point, a scalar equal to -GM/r for a point mass.
Gravitational quantum states of neutrons
Discrete energy levels of ultracold neutrons bouncing in Earth's gravity above a mirror, first observed in 2002; gravity resonance spectroscopy tests gravity at micrometer scales.
Gravitational redshift
Gravitational redshift, also called the Einstein shift, is the shift of light's frequency between points at different gravitational potential, a classical test of general relativity verified from Harvard's tower to satellites.
Gravitational redshift experiments
Gravitational redshift experiments compare identical clocks at different heights in a gravitational field against general relativity's prediction, from the 1960 Harvard tower tests to satellite and atomic-clock tests.
Gravitational search algorithm
The gravitational search algorithm (GSA) is a population-based metaheuristic introduced by Rashedi, Nezamabadi-pour, and Saryazdi in 2009 that mimics gravitational attraction between masses.
Gravitational singularity
A gravitational singularity is a location in spacetime, predicted by general relativity, where curvature and density grow without bound, as at black hole centers and the Big Bang.
Gravitational slip
Gravitational slip is the difference between the two scalar metric potentials in a perturbed expanding universe. A nonzero slip signals a departure from general relativity or anisotropic stress, altering structure growth and lensing.
Gravitational time dilation
Gravitational time dilation is the general relativity prediction that clocks run more slowly deeper in a gravitational field; near Earth the effect is about 10⁻¹⁶ per meter of height.
Gravitational wave
A gravitational wave, also called gravitational radiation, is a ripple in spacetime moving at the speed of light, predicted by Einstein in 1916 and first detected by LIGO in 2015.
Gravitational wave background
A gravitational wave background is a stochastic, noise-like signal from many overlapping, unresolved gravitational waves; in 2023 pulsar timing arrays reported evidence for a nanohertz background, likely from supermassive black hole binaries.
Gravitational wave background from SMBH binaries
The gravitational wave background from supermassive black hole binaries is a stochastic nanohertz signal from binaries in merged galaxies, detected by pulsar timing arrays in June 2023.