Theory of relativity

two interrelated physics theories by Albert Einstein

In physics, spacetime, also called the space-time continuum, is a mathematical model that fuses the three dimensions of space and the one dimension of time into a single four-dimensional continuum. Spacetime diagrams are useful in visualizing and understanding relativistic effects, such as how different observers perceive where and when events occur.

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.

frame of reference not undergoing acceleration

physics principle stating that the laws of physics must be the same in all reference frames

mass of a physical system independent of its motion; equals its total mass when at rest

unique path of an object as it travels through 4-dimensional spacetime

In special relativity, a four-vector (or 4-vector, sometimes Lorentz vector) is an element of a four-dimensional vector space object with four components, which transform under Lorentz transformations with respect to a change of basis. Its magnitude is determined by an indefinite quadratic form, the preservation of which defines the Lorentz transformations, which include spatial rotations and boosts (a change by a constant velocity to another reference frame).

physics principle that quantum theories reproduce classical physics in the limit of large quantum numbers, formulated by Niels Bohr in 1920

thumb|330x330px|Because the sphere travels faster than light, the observer sees nothing until it has already passed. Then, two images appear: one of the sphere arriving (on the right) and one of it departing (on the left). Faster-than-light (superluminal or supercausal) travel and communication are the conjectural propagation of matter or information faster than the speed of light in vacuum (). The special theory of relativity implies that only particles with zero rest mass (i.e., photons) may travel at the speed of light, and that nothing may travel faster.

theoretical foundation of Newtonian mechanics

path taken by a flash of light through spacetime

elapsed time between two events as measured by a clock that passes through both events

group of isometries of Minkowski spacetime

time dilation due to gravitational potential

theory of motion and forces for objects close to the speed of light

mathematical object that describes the electromagnetic field in spacetime

effect due to rotation in special relativity

relativistic vector field

view that neither the future nor the past exist

prediction that an accelerating observer will observe blackbody radiation where an inertial observer would observe none

in physics, situation or occurrence located at a specific point in space and time

quantum mechanics taking into account particles near or at the speed of light

mathematical model used in general relativity

coordinate system on a subset of Minkowski space adapted to a uniformly accelerating observer undergoing hyperbolic motion

paradox involving the impossibility of a rotating rigid disk in special relativity

convention for synchronising clocks at different places by means of signal exchanges

quantity in the theory of relativity which is invariant under a Lorentz transformation

concept in mathematical physics

thought experiment in special relativity: “a string hangs between two spaceships that start accelerating simultaneously equally in an inertial frame; will the string break?”

Time scale

overview about the criticism of the theory of relativity

Wikimedia list article

concept of modern physics theories that they should, under some circumstances, approximate the predictions of classical physics

1923 silent film about the theory of relativity directed by Max Fleischer and Dave Fleischer

Models of black holes without gravitational singularities

category of star

Debate about priority credit for the theories of general and special relativity

motion of an object with constant proper acceleration in special relativity

combination of relativistic and quantum concepts

In physics, specifically for special relativity and general relativity, a four-tensor is an abbreviation for a tensor in a four-dimensional spacetime.

mathematical transformation in physics that moves the times of events through a common interval

length of an object in the object's rest frame

1922 silent film

rotation independent of any external reference

written work by Albert Einstein