"General relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics."
A theory that gravity is the result of the curvature of space-time caused by the presence of mass and energy.
Special Relativity: The theory of special relativity deals with the relationship between space and time and how it is affected by the movement of the observer.
General Relativity: The theory of general relativity describes how mass and energy affect the curvature of space and time.
Gravity: Gravity is the force that pulls two objects towards each other. In general relativity, gravity is the curvature of spacetime caused by a mass or energy.
Black Holes: A black hole is a region of spacetime in which gravity is so strong that nothing, not even light, can escape.
Event Horizons: An event horizon is the boundary around a black hole beyond which nothing can escape.
Gravitational Waves: Gravitational waves are ripples in the curvature of spacetime, caused by the movement of massive objects.
Time Dilation: Time dilation is a phenomenon where time passes slower for objects that are moving near the speed of light.
Space-time Diagrams: Space-time diagrams are diagrams that show the relationship between space and time.
Energy-Momentum Tensor: The energy-momentum tensor describes the distribution of energy and momentum in spacetime.
Geodesics: Geodesics are the shortest paths between two points in curved spacetime.
Cosmology: Cosmology is the study of the origin, evolution, and structure of the universe.
Gravitational Lensing: Gravitational lensing is a phenomenon where the curvature of spacetime causes light to bend around massive objects.
Frame Dragging: Frame dragging is a phenomenon where the rotation of a massive object causes nearby spacetime to rotate as well.
Dark Matter: Dark matter is a hypothetical substance that is believed to make up most of the matter in the universe.
Dark Energy: Dark energy is a hypothetical form of energy that is believed to be responsible for the accelerating expansion of the universe.
Singularities: A singularity is a point in spacetime where the curvature becomes infinite.
Quantum Mechanics: Quantum mechanics is the study of the behavior of particles on a very small scale.
Unified Field Theory: A unified field theory is a theoretical framework that seeks to unify all of the fundamental forces of nature.
Curvature of a plane: A plane's curvature refers to how much it bends or slopes at any given point. In general relativity, a plane's curvature is usually negligible, as it is flat.
Gaussian curvature: The Gaussian curvature is the curvature measured at a point on a curved surface, and is defined as the product of the two principal curvatures at that point.
Ricci curvature: The Ricci curvature measures the rate at which the volume of a surface changes when it is curved. It is a tensor quantity that is also used in general relativity to describe the curvature of space-time.
Weyl curvature: The Weyl curvature is a tensor quantity that measures the curvature of spacetime in a locally anisotropic way – a way that is not uniform in every direction. This type of curvature arises in the presence of gravitational waves and is responsible for the stretching and squeezing of space-time.
Torsion: Torsion is a measure of how much a curve in space-time twists or turns as it moves along space-time. It is usually zero in classical general relativity, but certain extensions of the theory allow for non-zero torsion.
Holonomy: Holonomy measures the tendency of vectors in space-time to undergo rotational or translational changes as they are moved in loops around a particular region of space-time.
Cosmic curvature: Cosmic curvature refers to the overall curvature of space-time across the entire universe. In the standard model of cosmology, the universe is considered to be flat or nearly flat, with only small deviations from perfect flatness.
Intrinsic curvature: Intrinsic curvature is the curvature of a surface or space at a particular point, independent of the embedding of the surface or space in a larger space.
Extrinsic curvature: Extrinsic curvature is the curvature of a surface or space with respect to its embedding in a larger space. It is also sometimes called the bending of a surface.
Negative curvature: Negative curvature describes a type of geometry where the angles of a triangle add up to less than 180 degrees. This type of curvature is found in hyperbolic spaces and is thought to be present in the universe on extremely large scales.
Positive curvature: Positive curvature describes a type of geometry where the angles of a triangle add up to more than 180 degrees. This type of curvature is found in spherical spaces and is thought to be present in the universe on extremely small scales.
"General relativity generalizes special relativity and refines Newton's law of universal gravitation, providing a unified description of gravity as a geometric property of space and time or four-dimensional spacetime."
"In particular, the curvature of spacetime is directly related to the energy and momentum of whatever matter and radiation are present."
"Some predictions of general relativity, however, are beyond Newton's law of universal gravitation in classical physics."
"These predictions concern the passage of time, the geometry of space, the motion of bodies in free fall, and the propagation of light, and include gravitational time dilation, gravitational lensing, the gravitational redshift of light, the Shapiro time delay, and singularities/black holes."
"So far, all tests of general relativity have been shown to be in agreement with the theory."
"The time-dependent solutions of general relativity enable us to talk about the history of the universe and have provided the modern framework for cosmology, thus leading to the discovery of the Big Bang and cosmic microwave background radiation."
"Reconciliation of general relativity with the laws of quantum physics remains a problem, however, as there is a lack of a self-consistent theory of quantum gravity."
"Einstein's theory has astrophysical implications, including the prediction of black holes—regions of space in which space and time are distorted in such a way that nothing, not even light, can escape from them."
"Microquasars and active galactic nuclei are believed to be stellar black holes and supermassive black holes."
"It also predicts gravitational lensing, where the bending of light results in multiple images of the same distant astronomical phenomenon."
"Other predictions include the existence of gravitational waves, which have been observed directly by the physics collaboration LIGO and other observatories."
"In addition, general relativity has provided the base of cosmological models of an expanding universe."
"Widely acknowledged as a theory of extraordinary beauty, general relativity has often been described as the most beautiful of all existing physical theories."
"General relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915."
"General relativity provides a unified description of gravity as a geometric property of space and time or four-dimensional spacetime."
"These predictions concern the passage of time, the geometry of space, the motion of bodies in free fall, and the propagation of light, and include gravitational time dilation, gravitational lensing, the gravitational redshift of light, the Shapiro time delay, and singularities/black holes."
"So far, all tests of general relativity have been shown to be in agreement with the theory."
"The time-dependent solutions of general relativity enable us to talk about the history of the universe and have provided the modern framework for cosmology, thus leading to the discovery of the Big Bang and cosmic microwave background radiation."
"Reconciliation of general relativity with the laws of quantum physics remains a problem, however, as there is a lack of a self-consistent theory of quantum gravity."