Related papers: The Volume Inside a Black Hole
Event Horizon, a null hypersurface defining the boundary of the black hole region of a spacetime, is not particularly useful for evolving black holes since it is non-local in time. Instead, one uses the more tangible concept of Apparent…
We study the property of matter in equilibrium with a static, spherically symmetric black hole in D-dimensional spacetime. It requires this kind of matter has an equation of state (\omega\equiv p_r/\rho=-1/(1+2kn), k,n\in \mathbb{N}), which…
In general relativity, isolated black holes are invisible due to an infinitely large redshift of photons propagating from the event horizon to the remote observer. However, the dark shadow (silhouette) of a black hole can be visible on the…
A model is proposed for the interior of a neutral non-rotating black hole. It consists of an ideal fluid with density $\r$ and a negative pressure $p$, obeying an equation of state $p=-\xi\r$. In order to have a solution, $\xi$ must lie in…
We argue that a genuine image of the black hole viewed by a distant observer is not its shadow, but a more compact event horizon image probed by the luminous matter plunging into black hole. The external border of the black hole shadow is…
Black hole physics currently lacks a fully coherent understanding of the black hole mass (density), entropy, and interior (non-)singularity. These concepts are related to the black hole radius, area (of the horizon), and volume (within the…
In accordance with current models of the accelerating Universe as a spacetime with a positive cosmological constant, new results about a cosmological upper bound for the area of stable marginally outer trapped surfaces are found taking into…
The geometry of black hole spacetimes can be probed with exquisite precision in the gravitational-wave window, and possibly also in the optical regime. We study the accretion of bright spots -- objects which emit strongly in the optical or…
Christodoulou and Rovelli have shown that black holes have large interiors that grow asymptotically linearly in advanced time, and speculated that this may be relevant to the information loss paradox. We show that there is no simple…
An imploding shell of radiation is shown to create a 2-D black hole within the framework of the ``R=T'' theory. The radius of the horizon is given by 1/(2M), where M is the mass of the black hole. The topology of the central singularity is…
An action principle for spacetimes with the topology of an Euclidean black-hole is given. The gravitational field is described by the ordinary volume degrees of freedom plus additional surface fields at the horizon. The surface degrees of…
Regarding the volume as independent thermodynamic variable we point out that black hole horizons can hide positive heat capacity and specific heat. Such horizons are mechanically marginal, but thermally stable. In the absence of a canonical…
There is persistent and endemic confusion between the true (future) horizon and the illusory (past) horizon of a black hole. The illusory horizon is the redshifting surface of matter that fell into the black hole long ago. A person who…
The presence of a bright "photon ring" surrounding a dark "black hole shadow" has been discussed as an important feature of the observational appearance of emission originating near a black hole. We clarify the meaning and relevance of…
We describe 4D evaporating black holes as quantum field configurations by solving the semi-classical Einstein equation $G_{\mu\nu}=8\pi G \langle \psi|T_{\mu\nu}|\psi \rangle$ and quantum matter fields in a self-consistent manner. As the…
Some approaches to quantization of the horizon area of black holes are discussed. The maximum entropy of a quantized surface is demonstrated to be proportional to the surface area in the classical limit. This result is valid for a rather…
With a help of a generalized Raychaudhuri equation non-expanding null surfaces are studied in arbitrarily dimensional case. The definition and basic properties of non-expanding and isolated horizons known in the literature in the 4 and 3…
There are now multiple direct probes of the region near black hole horizons, including direct imaging with the Event Horizon Telescope (EHT). As a result, it is now of considerable interest to identify what aspects of the underlying…
Modes of physical fields which are located inside a horizon and which cannot be observed by a distant observer are identified with dynamical degrees of freedom of a black hole. A new invariant statistical mechanical definition of a…
Black holes in General Relativity are described by space-time metrics that are simpler in comparison to non-vacuum compact objects. However, given the universality of the gravitational pull, it is expected that dark matter accumulates…