Region outside of a rotating black hole's event horizon
At the ergospheres (shown here in violet for the outer and red for the inner one), the temporal metric coefficient gtt becomes negative, i.e., acts like a purely spatial metric component. Consequently, timelike or lightlike worldlines within this region must co-rotate with the inner mass. Cartesian projection, equatorial perspective.[1]
In astrophysics, the ergosphere is a region located outside a rotating black hole's outer event horizon. Its name was proposed by Remo Ruffini and John Archibald Wheeler during the Les Houches lectures in 1971 and is derived from Ancient Greek ἔργον (ergon) 'work'. It received this name because it is theoretically possible to extract energy and mass from this region. The ergosphere touches the event horizon at the poles of a rotating black hole and extends to a greater radius at the equator. A black hole with modest angular momentum has an ergosphere with a shape approximated by an oblate spheroid, while faster spins produce a more pumpkin-shaped ergosphere. The equatorial (maximal) radius of an ergosphere is the Schwarzschild radius, the radius of a non-rotating black hole. The polar (minimal) radius is also the polar (minimal) radius of the event horizon which can be as little as half the Schwarzschild radius for a maximally rotating black hole.[2]
^Visser, Matt (15 Jan 2008). "The Kerr spacetime: A brief introduction". p. 35. arXiv:0706.0622 [gr-qc].
^Griest, Kim (26 February 2010). "Physics 161: Black Holes: Lecture 22" (PDF). Archived (PDF) from the original on 2012-04-03. Retrieved 2011-10-19.
In astrophysics, the ergosphere is a region located outside a rotating black hole's outer event horizon. Its name was proposed by Remo Ruffini and John...
extracted from a rotating black hole. The process takes advantage of the ergosphere – a region of spacetime around the black hole dragged by its rotation...
radiation can escape normally from the ergosphere. Through the Penrose process, objects can emerge from the ergosphere with more energy than they entered...
an ergosphere outside the event horizon, in which spacetime itself begins to rotate, in a phenomenon known as frame-dragging. Since the ergosphere is...
rotate with the black hole; the region where this holds is called the ergosphere. The light from distant sources can travel around the event horizon several...
This can happen through the Penrose process inside the black hole's ergosphere, in the volume outside its event horizon. In some cases of energy extraction...
rotating black holes where, for any object entering a zone known as the ergosphere, rotation is inevitable. Such effects can again be tested through their...
ring-shaped object. This results in two event horizons, as well as an ergosphere, which draw closer together as the spin of the singularity increases....
a spinning black hole is surrounded by a region of space, called the ergosphere, within which standing still (with respect to the black hole's spin) is...
types include: The Cauchy and Killing horizons. The photon spheres and ergospheres of the Kerr solution. Particle and cosmological horizons relevant to...
causes the space within an oblate spheroid-shaped volume, called the "ergosphere", to be dragged around with the black hole. Mass falling into this volume...
Kerr–Newman metric contain Killing horizons, which can coincide with their ergospheres. For this spacetime, the corresponding Killing horizon is located at...
BTZ black hole contains an inner and an outer horizon, analogous to an ergosphere. Since (2+1)-dimensional gravity has no Newtonian limit, one might fear[why...
gravity is strong enough that photons are forced to travel in orbits. Ergosphere – region located outside a rotating black hole. Hawking radiation – black-body...
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