Traversing a black-and-white hole in free fall and rise

2020 ◽  
Vol 33 (4) ◽  
pp. 460-465
Author(s):  
Andreas Trupp
Keyword(s):  
Black Holes ◽  
Gravity Field ◽  
Free Fall ◽  
Spherical Body ◽  
Relativity Principle ◽  
White Hole ◽  
Schwarzschild Metric ◽  
Temporal Interval ◽  
Black And White ◽  
Schwarzschild Radius

It is shown that a traverse of a Black-and-White Hole (through a shaft in the interior of the central, spherical body) in free radial fall and rise is described by the Schwarzschild metric without any ambiguity. In other words, all Black Holes can also be White Holes. The relativity principle, according to which both the freely falling/rising observer Alice and a second observer Bob (sitting outside of the gravity field) have to measure the same temporal interval for the complete trip, is observed [(Δt)/(Δτ) = 1]. In the interior of the Schwarzschild radius, Alice's time τ is reversed. Kruskal charts do not present an obstacle to this result, since quadrant II can be used for ingoing traffic only, but not for outgoing traffic.

scholarly journals Small Black/White Hole Stability and Dark Matter

Universe ◽  
2018 ◽  
Vol 4 (11) ◽  
pp. 127 ◽  
Author(s):  
Carlo Rovelli ◽  
Francesca Vidotto
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dark Matter ◽  
Loop Quantum Gravity ◽  
Quantum Superposition ◽  
White Hole ◽  
Small Black Hole ◽  
Black And White ◽  
Minimal Eigenvalue ◽  
Simple Quantum

We show that the expected lifetime of white holes formed as remnants of evaporated black holes is consistent with their production at reheating. We give a simple quantum description of these objects and argue that a quantum superposition of black and white holes with large interiors is stable, because it is protected by the existence of a minimal eigenvalue of the area, predicted by Loop Quantum Gravity. These two results support the hypothesis that a component of dark matter could be formed by small black hole remnants.

scholarly journals Gravity cells as a necessary link in string theory. The formula for the gravitational constant, the formula for the mass of the electron, the formula for the minimum distance of the gravitational interaction. The coincidence of the results obtained by the formulas and the experimental data.

2021 ◽  
Author(s):  
Andrey Chernov
Keyword(s):  
Experimental Data ◽  
Black Holes ◽  
String Theory ◽  
Minimum Distance ◽  
Gravitational Constant ◽  
Casimir Effect ◽  
Gravitational Interaction ◽  
Fundamental Constants ◽  
Vibrational Velocity ◽  
Schwarzschild Radius

Abstract In this study, a new concept is introduced into physics - gravitational cells. The gravitational cell hypothesis was organically integrated into string theory. As a result, using the Schwarzschild radius formula and the Coulomb formula, a gravitational formula in the region of black holes was obtained on the basis of two fundamental constants, and its exact value was determined. The value of the "usual" gravitational constant was also confirmed and the mass of the gravitational cell was obtained. The introduction of the hypothesis of gravitational cells into string theory made it possible to apply Planck's formula to gravitational interaction. As a result, a formula for the energy of a gravitational quantum and a formula for the vibrational velocity of a gravitational string were obtained. On this basis, the formula for the mass of the electron was obtained and its value was calculated, which coincided with the experimental mass of the electron. The exact minimum distance of the gravitational interaction was determined by the formula for the vibrational velocity of the gravitational string. This calculated minimum distance completely coincided with the known experimental data obtained when determining the Casimir effect (force).

Light Inextensible Strings (Thread) Under Tension in the Schwarzschild Geometry

2021 ◽  
Vol 03 (02) ◽  
pp. 2150005
Author(s):  
Robin K. S. Hankin
Keyword(s):  
Free Fall ◽  
Computer Algebra Systems ◽  
Lagrange Equations ◽  
Schwarzschild Metric ◽  
Schwarzschild Geometry ◽  
Homework Problem ◽  
Straight Line ◽  
Taut Strings ◽  
Proper Length ◽  
Insight Into

Light inextensible string under tension is a stalwart feature of elementary physics. Here I show how considering such a string in the vicinity of a black hole, with the help of computer algebra systems, can generate insight into the Schwarzschild geometry in the context of an undergraduate homework problem. Light taut strings minimize their proper length, given by integrating the spatial component of the Schwarzschild metric along the string. The path itself is given by straightforward numerical solution to the Euler–Lagrange equations. If the string is entirely outside the event horizon, its closest approach to the singularity is tangential. At this point the string is visibly curved, surely a memorable and informative insight. The geometry of the Schwarzschild metric induces some interesting nonlocal phenomena: if the distance of closest approach is less than about [Formula: see text], the string self-intersects, even though it is everywhere under tension. Light taut strings furnish a third interpretation of the concept “straight line”, the other two being null geodesics and free-fall world lines. All the software used is available under the GPL.1

scholarly journals Magnonic Analog of Black- and White-Hole Horizons in Superfluid He3−B

2019 ◽  
Vol 123 (16) ◽  
Author(s):  
M. Človečko ◽  
E. Gažo ◽  
M. Kupka ◽  
P. Skyba
Keyword(s):  
White Hole ◽  
Black And White

scholarly journals Local free-fall temperature of Gibbons-Maeda-Garfinkle-Horowitz-Strominger black holes

2014 ◽  
Vol 89 (4) ◽  
Author(s):  
Yong-Wan Kim ◽  
Jaedong Choi ◽  
Young-Jai Park
Keyword(s):  
Black Holes ◽  
Free Fall ◽  
Fall Temperature

scholarly journals Dependence of acoustic surface gravity on geometric configuration of matter for axially symmetric background flows in the Schwarzschild metric

2015 ◽  
Vol 24 (14) ◽  
pp. 1550096 ◽  
Author(s):  
Pratik Tarafdar ◽  
Tapas K. Das
Keyword(s):  
Black Holes ◽  
Fluid Flow ◽  
Boundary Conditions ◽  
Equations Of State ◽  
Initial Boundary ◽  
Stationary Flow ◽  
Geometric Configuration ◽  
Surface Gravity ◽  
Axially Symmetric ◽  
Schwarzschild Metric

In black hole evaporation process, the mass of the hole anti-correlates with the Hawking temperature. This indicates that the smaller holes have higher surface gravity. For analogue Hawking effects, however, the acoustic surface gravity is determined by the local values of the dynamical velocity of the stationary background fluid flow and the speed of propagation of the characteristic perturbation embedded in the background fluid, as well as by their space derivatives evaluated along the direction normal to the acoustic horizon, respectively. The mass of the analogue system — whether classical or quantum — does not directly contribute to extremize the value of the associated acoustic surface gravity. For general relativistic axially symmetric background fluid flow in the Schwarzschild metric, we show that the initial boundary conditions describing such accretion influence the maximization scheme of the acoustic surface gravity and associated analogue temperature. Aforementioned background flow onto black holes can assume three distinct geometric configurations. Identical set of initial boundary conditions can lead to entirely different phase-space behavior of the stationary flow solutions, as well as the salient features of the associated relativistic acoustic geometry. This implies that it is imperative to investigate how the measure of the acoustic surface gravity corresponding to the accreting black holes gets influenced by the geometric configuration of the inflow described by various thermodynamic equations of state. Such investigation is useful to study the effect of Einstenian gravity on the nonconventional classical features as observed in Hawking like effect in a dispersive medium in the limit of a strong dispersion relation.

scholarly journals Gauge dependence and self-force from Galilean to Einsteinian free fall, compact stars falling into black holes, Hawking radiation and the Pisa tower at the general relativity centennial

2016 ◽  
Vol 13 (08) ◽  
pp. 1630014 ◽  
Author(s):  
Alessandro D. A. M. Spallicci ◽  
Maurice H. P. M. van Putten
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Undergraduate Students ◽  
Hawking Radiation ◽  
Mass Formula ◽  
Center Of Mass ◽  
Free Fall ◽  
Compact Stars ◽  
Self Force

Obviously, in Galilean physics, the universality of free fall implies an inertial frame, which in turns implies that the mass [Formula: see text] of the falling body is omitted (because it is a test mass; put otherwise, the center of mass of the system coincides with the center of the main, and fixed, mass [Formula: see text]; or else, we consider only a homogeneous gravitational field). Conversely, an additional (in the opposite or same direction) acceleration proportional to [Formula: see text] would rise either for an observer at the center of mass of the system, or for an observer at a fixed distance from the center of mass of [Formula: see text]. These elementary, but overlooked, considerations fully respect the equivalence principle (EP) and the (local) identity of an inertial or a gravitational pull for an observer in the Einstein cabin. They value as fore-runners of the self-force and gauge dependency in general relativity. Because of its importance in teaching and in the history of physics, coupled to the introductory role to Einstein’s EP, the approximate nature of Galilei’s law of free fall is explored herein. When stepping into general relativity, we report how the geodesic free fall into a black hole was the subject of an intense debate again centered on coordinate choice. Later, we describe how the infalling mass and the emitted gravitational radiation affect the free fall motion of a body. The general relativistic self-force might be dealt with to perfectly fit into a geodesic conception of motion. Then, embracing quantum mechanics, real black holes are not classical static objects any longer. Free fall has to handle the Hawking radiation, and leads us to new perspectives on the varying mass of the evaporating black hole and on the varying energy of the falling mass. Along the paper, we also estimate our findings for ordinary masses being dropped from a Galilean or Einsteinian Pisa-like tower with respect to the current state of the art drawn from precise measurements in ground and space laboratories, and to the constraints posed by quantum measurements. Appendix A describes how education physics and high impact factor journals discuss the free fall. Finally, case studies conducted on undergraduate students and teachers are reviewed.

scholarly journals From black hole to white hole via the intermediate static state

2021 ◽  
pp. 2150117
Author(s):  
G. E. Volovik
Keyword(s):  
Black Hole ◽  
Intermediate State ◽  
Coordinate Transformations ◽  
De Sitter ◽  
Static State ◽  
White Hole ◽  
Black And White ◽  
Zero Entropy ◽  
Macroscopic Quantum Tunneling ◽  
De Sitter Universe

We discuss the macroscopic quantum tunneling from the black hole to the white hole of the same mass. Previous calculations in [G. E. Volovik, Universe 6, 133 (2020)] demonstrated that the probability of the tunneling is [Formula: see text], where [Formula: see text] is the entropy of the Schwarzschild black hole. This in particular suggests that the entropy of the white hole is with minus sign the entropy of the black hole, [Formula: see text]. Here, we use a different way of calculations. We consider three different types of the hole objects: black hole, white hole and the fully static intermediate state. The probability of tunneling transitions between these three states is found using singularities in the coordinate transformations between these objects. The black and white holes are described by the Painleve–Gullstrand coordinates with opposite shift vectors, while the intermediate state is described by the static Schwarzschild coordinates. The singularities in the coordinate transformations lead to the imaginary part in the action, which determines the tunneling exponent. For the white hole the same negative entropy is obtained, while the intermediate state — the fully static hole — has zero entropy. This procedure is extended to the Reissner–Nordström black hole and to its white and static partners, and also to the entropy and temperature of the de Sitter Universe.

Sign in / Sign up

Export Citation Format

Share Document