Horizon (general relativity)

A horizon is a boundary in spacetime satisfying prescribed conditions.

There are several types of horizons that play a role in Albert Einstein's theory of general relativity:

  • Absolute horizon, a boundary in spacetime in general relativity inside of which events cannot affect an external observer
  • Event horizon, a boundary in spacetime beyond which events cannot affect the observer, thus referring to a black hole's boundary and the boundary of an expanding universe
  • Apparent horizon, a surface defined in general relativity
  • Cauchy horizon, a surface found in the study of Cauchy problems
  • Cosmological horizon, a limit of observability
  • Killing horizon, a null surface on which there is a Killing vector field
  • Particle horizon, the maximum distance from which particles can have travelled to an observer in the age of the universe

See also

  • Horizon (disambiguation)
This article is issued from Wikipedia. The text is available under Creative Commons Attribution-Share Alike 4.0 unless otherwise noted. Additional terms may apply for the media files.