What is on the other side of the black hole
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Exploring the Other Side of a Black Hole
Schwarzschild Black Hole Singularity and Antigravity Region
The concept of what lies beyond a black hole has intrigued scientists for decades. Recent research has provided some fascinating insights into this enigmatic region. One study delves into the Schwarzschild black hole, a non-rotating black hole solution in general relativity, and explores the space beyond its singularity using Kruskal-Szekeres coordinates. This study reveals that the gravitational constant switches sign abruptly at the singularity, suggesting the presence of a region of antigravity on the other side1. This antigravity region is a prediction of local (Weyl) scale invariant geodesically complete spacetimes, which aim to improve upon classical general relativity and string theory1.
Geodesical Completion and Observer Perspectives
The research further computes the geodesics for this new black hole model, demonstrating that all geodesics of a test particle are complete. This means that an ideal observer, starting their journey in the usual space of gravity, can traverse the singularity and reach the other side in a finite amount of proper time1. However, it is important to note that an observer outside the event horizon cannot verify the existence of this phenomenon. The significance of this finding lies in its potential to aid in the construction of a more accurate theory of black holes and cosmology, particularly in regions close to and beyond singularities1.
Observing the Event Horizon and Black Hole Shadow
While the theoretical exploration of what lies beyond a black hole is profound, observational evidence of black holes themselves is equally crucial. The shadow of a black hole, cast by its event horizon, provides a unique opportunity for such observations. For instance, the black hole at the center of our galaxy, associated with the radio source Sagittarius A* (Sgr A*), is a prime candidate for such studies. The shadow of Sgr A*, with an apparent diameter of approximately 10 gravitational radii, is due to the bending of light by the black hole and is nearly independent of the black hole's spin or orientation2.
Imaging the Black Hole Shadow
The predicted size of this shadow for Sgr A* is around 30 microarcseconds, which is within the resolution capabilities of current radio interferometers. If the black hole is maximally spinning and viewed edge-on, the shadow will be slightly offset and flattened on one side2. With advancements in very long baseline interferometry at submillimeter wavelengths, there is a realistic expectation of imaging the event horizon of a black hole in the near future, assuming the accretion flow is optically thin in this region of the spectrum2.
Conclusion
In summary, the exploration of what lies beyond a black hole's singularity reveals a region of antigravity, as predicted by advanced theoretical models. While direct observation of this region remains beyond our current capabilities, the study of black hole shadows, such as that of Sgr A*, offers a promising avenue for understanding these cosmic phenomena. As observational techniques continue to improve, we may soon gain unprecedented insights into the nature of black holes and the mysteries that lie beyond their event horizons.
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Most relevant research papers on this topic
Journey Beyond the Schwarzschild Black Hole Singularity
The geodesical completion of the Schwarzschild black hole in four dimensions allows an ideal observer to reach the other side of the singularity in a finite amount of proper time, improving classical general relativity and string theory.
Viewing the Shadow of the Black Hole at the Galactic Center
The event horizon of Sgr A*, the Galactic center's black hole, may be observable with submillimeter interferometry within a few years, providing a realistic expectation of imaging the black hole within a few years.
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A traversable wormhole connects two different spacetimes, influencing objects in one space and affecting those in the other space, with potential applications in black hole orbits and black hole-star binary systems.
Statistical mechanics of a two-dimensional black hole
This paper presents the statistical mechanics of a two-dimensional black hole, enabling the construction of thermal partition functions and arbitrary density matrices.
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Quantum mechanical effects cause black holes to create and emit particles as if they were hot bodies, leading to their eventual disappearance and violation of the classical law of event horizon area not decreasing.
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The 2-2-hole, a novel horizonless configuration, may be the nearly black end point of gravitational collapse, with a shrinking volume and timelike curvature singularity.
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The universe may have been born as a baby universe on the other side of a black hole event horizon, potentially explaining the origin of inertia and completing Einstein's general theory of relativity.
Black holes in general relativity
A stationary black hole must have a topologically spherical boundary and be axisymmetric if it is rotating, establishing the conjecture that any stationary black hole is a Kerr solution.
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Dark matter and dark energy may create black holes in the early universe, potentially affecting the Big Bang and the Big Crunch theories.
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