- Not to be confused with the technological singularity.
- Please see Black Hole section at article Star.
- It is a type of Stellar Remnant
Black Hole: A star of over 30 MSol initial mass forms a sufficiently massive stellar core remnant during its core collapse such that the neutron degenerate dwarf formed is in excess of 5-10 MSol. At this mass range, the neutron star is dense enough that its radius falls within its own Schwarzschild radius, the radius at which the escape velocity for an object due to gravity equals or exceeds that of the speed of light. The neutron star in this case has fallen beyond the region in which it can be observed by an outside observer (known as the "Event Horizon"), the core remnant within collapsing to a point-singularity of infinite density.
As gravity is directly related to the topology of spacetime in General Relativity, the rate of the passage of time experienced by an object near the event horizon relative to an observer at infinity slows down as the event horizon is approached, stopping altogether at the event horizon. This likewise means (since light is a waveform with a frequency) that as the event horizon is approached by an object, the frequency of its light or transmissions will decrease (or, said another way, its light-wavelength will be spatially stretched and redshifted relative to an observer at infinity). Taken together, an object approaching an event horizon will appear to move slower and slower, and in fact will never actually reach the event horizon relative to an observer at infinity, its light or transmissions becoming increasingly redshifted until it can no longer be seen in visible light. Note that from the perspective of the object falling into the event horizon, time for objects at infinity appear to be moving much faster, and incoming light and transmissions appear blueshifted. The event horizon is not a physical boundary surface, but rather a mathematical one.
- The Schwarzschild Black Hole (sometimes referred to as a "static" black hole) is the simplest form of black hole, and is defined entirely by the singularity surrounded by its event horizon. Objects above the event horizon may potentially escape the gravity of the black hole, whereas objects below it may not and are doomed to be drawn directly onto a trajectory that inevitably leads to the singularity and crushed to infinite density.
- The Kerr Black Hole (sometimes referred to as a "rotating" black hole) is a more complicated structure. The singularity of a Kerr Black Hole is characterized by a (generally large) non-zero angular momentum. One of the effects this has on the topology of the black hole is that in addition to the standard event horizon surrounding the singularity, there exists another mathematical boundary known as the static limit, or ergosphere. The ergosphere is an oblate spheroidal mathematical boundary tangent to the event horizon at the poles of rotation with a distended "equatorial bulge" above the event horizon. The region between the mathematical surfaces of the event horizon and the ergosphere is a region in which it is impossible for an object to remain stationary due to the phenomenon of "frame-dragging". Essentially, the rotation of the black hole "drags" the fabric of spacetime along with it as it rotates. Within the region of the ergosphere, the spacetime frame itself is being dragged at a rate faster than the speed of light, meaning that any object moving within the spacetime-frame within the ergosphere opposite the direction of rotation of the black hole would need to be able to move faster than light in order to remain stationary or move in the opposite direction. Unlike the event horizon, an object may still escape from the ergosphere region.
A black hole in a system with a close-orbiting companion star may pull material from the companion, leading to the formation of an accretion disk of superheated plasma around the black hole, which may further lead to the formation of a microquasar.
No information yet available.
Central Galactic Mass
No information available.
Black Holes of Galaxias
- Closest known Black Holes:
No information yet available.
Worlds & Sectors (Astrography)
World Listing: 1105
References & Contributors (Sources)
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