相关论文: Life under a black sun

Rotating black holes are the most powerful source of energy in the known universe, and are the cause of some of the most spectacular and extreme astronomical phenomena. The goal of this article is to analyze in simple terms the physics of…

In the teleparallel equivalent of general relativity the energy density of asymptoticaly flat gravitational fields can be naturally defined as a scalar density restricted to a three dimensional spacelike hypersurface. The scalar density has…

We consider the contribution to the entropy from fields in the background of a curved time-independent metric. To account for the curvature of space, we postulate a position-dependent UV cutoff. We argue that a UV cutoff on energy naturally…

We investigate electromagnetic and gravitational radiation generated during the process of the tidal stripping of a white dwarf star circulating a black hole. We go beyond Chandrasekhar's ideas and not only consider a white dwarf itself as…

In this paper we derive a class of rotating embedded black holes. Then we study Hawking's radiation effects on these embedded black holes. The surface gravity, entropy and angular velocity are given for each of these black holes.

A brief overview of the discovery that macroscopic black holes are thermodynamical systems is presented. They satisfy the laws of thermodynamics and are associated with a temperature and an entropy equal to one quarter of their horizon area…

In many models, dark matter particles can elastically scatter with nuclei in planets, causing those particles to become gravitationally bound. While the energy expected to be released through the subsequent annihilations of dark matter…

Without pretending to any rigour, we find a general expression of the electrostatic self-energy in static black holes with spherical symmetry. We determine the entropy bound of a charged object by assuming the existence of thermodynamics…

Virtually all massive galaxies, including our own, host central black holes ranging in mass from millions to billions of solar masses. The growth of these black holes releases vast amounts of energy that powers quasars and other weaker…

This paper deals with a cosmological model in which the universe is filled with tachyon dark energy in order to describe current and future accelerating expansion. We obtain that the simplest condition for the regime of phantom energy to…

In the teleparallel equivalent of general relativity the energy density of asymptotically flat gravitational fields can be naturaly defined as a scalar density restricted to a three-dimensional spacelike hypersurface $\Sigma$. Integration…

Black hole entropy is identified with the counting of the dynamical degrees of freedom of trapped gravitational modes continually sourced by the Hawking-Unruh process. In the context of linear perturbations of Schwarzschild spacetime the…

If life is sustained by a process of photosynthesis, not necessarily the same existing on Earth, the surface temperature of the star and the orbit of the host planet cannot be whatsoever. In fact the global life cycle, no matter how…

Primordial black holes are a viable dark matter candidate. They decay via Hawking evaporation. Energetic particles from the Hawking radiation interact with interstellar gas, depositing their energy as heat and ionization. For a sufficiently…

It is suggested that essentially all of the UHECRs we detect, including those at the highest energy, originate in our Galaxy. It is shown that even if the density of sources decreases with Galactic radius, then the anisotropy and…

An introduction is given to a meeting on the role of massive and stellar black holes in powering non-thermal activity in a rich variety of cosmic sources. Relevant properties of magnetized, spinning black holes are summarized and their…

We introduce a 'quasi-topological` term [1] in D=1+1 dimensions and the entropy for black holes is calculated [2]. The source of entropy in this case is justified by a non-null stress-energy tensor.

We consider Hawking radiation as due to a tunneling process in a black hole were quantum corrections, derived from Quantum Einstein Gravity, are taken into account. The consequent derivation, satisfying conservation laws, leads to a…

Accreting black holes in galactic X-ray sources are surrounded by hot plasma. The innermost part of these systems is likely a corona with different temperatures for ions and electrons. In the so-called low-hard state, hot electrons…

The comparison of geometrical properties of black holes with classical thermodynamic variables reveals surprising parallels between the laws of black hole mechanics and the laws of thermodynamics. Since Hawking's discovery that black holes…