abstract said:Abstract
We consider the radial geodesic motion of a massive particle into a black hole in isotropic coordinates, which represents the exterior region of an Einstein–Rosen bridge (wormhole). The particle enters the interior region, which is regular and physically equivalent to the asymptotically flat exterior of a white hole, and the particle's proper time extends to infinity. Since the radial motion into a wormhole after passing the event horizon is physically different from the motion into a Schwarzschild black hole, Einstein–Rosen and Schwarzschild black holes are different, physical realizations of general relativity. Yet for distant observers, both solutions are indistinguishable. We show that timelike geodesics in the field of a wormhole are complete because the expansion scalar in the Raychaudhuri equation has a discontinuity at the horizon, and because the Einstein–Rosen bridge is represented by the Kruskal diagram with Rindler's elliptic identification of the two antipodal future event horizons. These results suggest that observed astrophysical black holes may be Einstein–Rosen bridges, each with a new universe inside that formed simultaneously with the black hole. Accordingly, our own Universe may be the interior of a black hole existing inside another universe.
A black hole is a region of space where the gravitational pull is so strong that nothing, including light, can escape from it. This happens when a massive star collapses and its core becomes extremely dense.
Some theories suggest that inside a black hole, there is a singularity, which is a point of infinite density and gravity. This singularity could contain a whole universe, with its own set of physical laws and dimensions.
Nothing can escape from a black hole once it has crossed the event horizon, which is the point of no return. However, some particles can escape through Hawking radiation, a process theorized by physicist Stephen Hawking.
As matter falls into a black hole, it gets stretched and compressed by the intense gravitational force. This process is known as spaghettification. The matter is then crushed into the singularity at the center.
Currently, we do not have the technology to directly study black holes containing a universe. However, scientists use mathematical models and observations of the effects of black holes on their surroundings to understand their properties and behavior.