spacetime


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spacetime

The single physical entity into which the concepts of space and time can be unified such that an event may be specified mathematically by four coordinates, three giving the position in space and one the time. The path of a particle in spacetime is called its world line. The world line links events in the history of the particle.

The concept of spacetime was used by Einstein in both the special and the general theories of relativity. In special theory, where only inertial frames are considered, spacetime is flat. In the presence of gravitational fields, treated by general relativity, the geometry of spacetime changes: it becomes curved. The rules of geometry in curved space are not those of three-dimensional Euclidean geometry.

Matter tells spacetime how to curve: massive objects produce distortions and ripples in the local spacetime. The question of whether the spacetime of the real Universe is curved, and in what sense, has yet to be resolved. If the Universe contains sufficient matter, i.e. if the mean density of the Universe is high enough, then the spacetime of the Universe must be bent round on itself and closed.

References in periodicals archive ?
Among the more than two dozen major customers of SpaceTime, a decade-old Silicon Valley-based company, are FedEx, No.
in a region of spacetime where is there no energy, a state which is different from vacuum state everywhere in spacetime, equation (2.1) becomes
Therefore the first law of BH thermodynamics in this phase space for any spherically symmetric spacetime and for OH should be
We assume that time and the speed of light are absolute physical quantities that play the role of the independent variable such that the spacetime coordinate system is an n-dimensional space and one-dimensional of time [10].
Keywords: Static Conformal Mikowski Spacetime, Cosmological Constant, Einstein Field Equations
Einstein expressed these ideas of energy-mass as an integral part of warped spacetime.
According to Albert Einstein's General Theory of Relativity (1915), gravity causes spacetime to curve under the influence of mass--the more mass contained within a particular region of space, the greater the curvature will be at the boundary of that particular region.
This acts as a "wormhole" - a doorway or tunnel through the fabric of spacetime of the kind seen in countless sci-fi stories.
Einstein's theme of spacetime symmetry is highlighted and then related broadly to nursing and health.
At a news conference on June 7, mission scientists announced that the orbiting facility has surpassed the precision needed for future missions to detect spacetime disturbances.
They are where the curvature of spacetime is so steep that all paths lead inwards.
The news from the US last Thursday confirmed gravity waves - ripples in spacetime - had been detected by scientists a century after Albert Einstein predicted their existence.