Cauchy horizon
The Cauchy horizon (also Cauchy surface ), named after the French mathematician Augustin-Louis Cauchy , is a surface within the event horizon of rotating or charged black holes in astrophysics . The scientific definition of the Cauchy horizon is as follows: A Cauchy surface is a hypersurface of spacetime that can only intersect a causal curve exactly once .
Explanation
The general theory of relativity describes the gravitational interaction of matter and energy in a four-dimensional space - time using Einstein's field equations . A hypersurface like the Cauchy surface is three-dimensional in this 4D structure. The above The causal curve describes the curve that an object or observer travels within space-time. Such causal curves, however, cannot be continued into the past, which can also be deduced from the condition of the single intersection, which thus means that Cauchy horizons, like event horizons, are only permeable in one direction.
Strange effects on the Cauchy horizon
If an observer gets behind the Cauchy horizon on a geodesic , he can observe the entire past of the outside world as if in a time-lapse, since he reaches a region of infinite blue shift . If Cauchy surfaces are disturbed by objects crossing them, they become singular, which means that they are singular null hypersurfaces . According to these properties one can make the assumption that the domain of quantum gravity begins in them .
swell
- Chandrasekhar, S .: The Mathematical Theory of Black Holes , 1983, p. 214
- Townsend, PK : Black Holes , 1997
- Cauchy horizon on quantamagazine.org
Individual evidence
- ↑ Julius Pauleit: Black holes. In: Internship Project. Max Planck Institute for Radio Astronomy, February 14, 2020, accessed on May 27, 2020 .
- ↑ quoted from [1] Lexikon der Astronomie, accessed on April 27, 2020