Category:Spacetime

From Eurêka

Spacetime (Space-time) Four-dimensional continuum or “fabric” that results when space and time are unified. According to one theory there are 3.99999947 dimensions in spacetime.

1. Spacetime continuum Four-dimensional continuum with coordinates being three spatial dimensions and time. It is a way of representing the universe as suggested by the theory of relativity.
2. Spacetime curvature (Tidal gravity; Warpage of spacetime) Property of spacetime that causes freely falling particles that are initially moving along parallel world lines to subsequently move together or apart.
3. Geodesic Shortest path between two points in spacetime and therefore the path followed by photons.
4. Field equations In general relativity, the equations that describe the curvature of spacetime by connecting the metric to the distribution of matter and energy.
5. Metric Measure of distance in spacetime that is the same for all observers regardless of their state of motion.
6. Event Either, (1) Point in spacetime; that is, a location in space at a specific moment in time, or (2) Something that happens at a point in spacetime, e.g. the explosion of a firecracker.
7. Free falling objects Object on which no forces act except gravity.

Spatial dimension Any of the three dimensions of spacetime, other than time.

Spacetime diagram Diagram with time plotted upward and space plotted horizontally.

Minkowski diagram Representation of the three dimensions of space and one of time as two-dimensional graphs, developed by Lithuanian Hermann Minkowski.

1. World line Line in a Minkowski diagram representing the life history of a particle through spacetime.
2. Light cone Region of spacetime embraced by lines representing light rays in the Minkowski diagram. Events at a point in spacetime can be influenced only by events that occur in that point’s own past-light cone, and can have an influence only on events that lie in its own future light cone.

Schwarzschild geometry Geometry of spacetime around and inside a spherical, nonspinning hole.

Global methods Mathematical techniques, based on a combination of topology and geometry, for analyzing the structure of spacetime.

Wormhole (Spacetime bridge) Two regions of space, or even two separate cosmoses, that are joined as if through a higher dimension, a concept first put forward by Albert Einstein and Nathan Rosan in 1935. By the 1960s, the American physicist John Archibald Wheeler expanded the concept and coined its name, noting that if one applied the quantum theory to the geometry of spacetime as described by Einstein’s theory of relativity, one can conclude that very tiny fluctuations are taking place around us all the time. As a result, occasionally a piece of the universe might bulge out, forming a wormhole until it snapped, leaving an isolated entity of space and time disconnected from the universe. It has been described as either, (1) An Alice-in-Wonderland-type relativistic tunnel in the black hole’s core, or (2) A ‘handle’ in the topography of space connecting two widely separated locations in our universe.

1. Mouth Entrance to a wormhole. There is a mouth at each end of the wormhole.

Supertwisters (and, Worldtubes) Spacetime oddities.