General relativity

A black hole is an astronomical body so compact that its gravity prevents anything, including light, from escaping. Albert Einstein's theory of general relativity, which describes gravitation as the curvature of spacetime, predicts that any sufficiently compact mass will form a black hole. The boundary of no escape is called the event horizon. In general relativity, crossing a black hole's event horizon traps an object inside but produces no locally detectable change. General relativity also predicts that every black hole should have a central singularity, where the curvature of spacetime is infinite.

standard and classical physics theory of gravity and space

thumb|upright=1.3|A wormhole visualized as a two-dimensional surface. Route (a) is the shortest path through normal space between points 1 and 2; route (b) is a shorter path through a wormhole.

boundary of a region of spacetime from which one cannot escape once entered

direction and intensity of gravity in every point of space

field of theoretical physics

hypothetical region of spacetime that serves as the opposite of a black hole

location in space-time where the gravitational field of a celestial body becomes infinite

constant representing stress-energy density of the vacuum in Einstein's equation, which accounts for the rate of expansion of the universe

increase in distance between parts of the universe over time

field equations in general relativity

hypothesis that inertial and gravitational masses are equivalent

hypothetical planet between the Sun and Mercury

thumb|Artistic depiction of a fictional anti-gravity vehicle

set of ordinary differential equations governing cosmic expansion in a homogeneous and isotropic universe

gravitational wave event

subject of cosmology

standard surface gravity

thumb|400 px|Diagram regarding the confirmation of gravitomagnetism by Gravity Probe B

type of astronomy involving observation of gravitational waves

non-technical introduction to the theory of gravity by Albert Einstein

theorem

conjecture that, in general relativity, there is no naked singularity (i.e. one visible from future null infinity) generically

history of the general theory of relativity with contributions from Albert Einstein, Marcel Grossmann, David Hilbert and others

theory of a free spin-2 field; weak-field approximation of general relativity

theoretical physics principle

spherical area or region of space where gravity is strong enough that massless particles are forced to travel in orbits

the effect of the curvature of spacetime, predicted by general relativity, on a vector carried along with an orbiting body

Action that yields the Einstein field equations through the principle of least action

theorized concentration of light so intense that it forms an event horizon and becomes self-trapped

non-mainstream theory in physics remaining to be validated

system of units in which the gravitational constant is set to be a dimensionless number, such that mass has the units of [length]^(D−3) in D spacetime dimensions

nonsingular electromagnetic or gravitational wave held together in a confined region by the gravitational attraction of its own field energy

classification system for different theories of gravity

light-like boundary of the domain of validity of a Cauchy problem in general relativity

generalization of straight line to a curved space time

spatial geometry which is not "flat" or Euclidean

Precession of a gyroscope

general relativity model near the beginning of the universe

approximation of General Relativity

line segment of infinitesimally small length

field of cosmology

proposed theories of gravity

Calculations pertaining to orbits

non-technical introduction to the mathematics of general relativity

scale of time

result in general relativity

The '''Micro-Satellite à traînée Compensée pour l'Observation du Principe d'Equivalence (Micro-Satellite with Compensated Drag for Observing the Principle of Equivalence, MICROSCOPE''') is a class minisatellite operated by CNES to test the universality of free fall (the equivalence principle) with a precision to the order of , 100 times more precise than can be achieved on Earth. It was launched on 25 April 2016 alongside Sentinel-1B and other small satellites, and was decommissioned around 18 October 2018 after completion of its science objectives. The final report was published in 2022.

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book by Charles W. Misner

smallest circular orbit in which a test particle can stably orbit a massive object in general relativity

boundary in spacetime, defined with respect to the external universe, events inside which cannot affect an external observer

system of second-order differential equations describing the motion of a system of point particles with leading-order general-relativistic corrections

hypothetical process of shielding an object from the influence of a gravitational field

Special product of manifolds

motion of an object with constant proper acceleration in special relativity

electromagnetism in general relativity

cosmological model for a flat matter-only Friedmann–Lemaître–Robertson–Walker universe

apparent paradox in the context of general relativity

Spacetime modeled by four pointwise-orthonormal vector fields