1-3. Situation when falling within the Schwarzschild radius of a massive star
Suppose A is a supermassive cosmic nucleus and a black hole with a huge Schwarzschild radius of hundreds of billions of light-years or more. And let B be an observer in free fall within the Schwarzschild radius.
Within the Schwarzschild radius, light paths in all directions emanating from B cannot escape to the outside. Therefore, all optical paths are bent and lead to the central core of the universe.
That is, all optical paths in all directions emitted from the falling observer B are connected to the central nucleus A. Here, the optical paths between the two points A ⇔ B are all the shortest distances, and are equidistant. Therefore, when viewed from the observer B, the spatial structure is such that the central nucleus A exists equidistantly in all directions.
In other words, the observer B is wrapped in the surface of the central nucleus A and becomes a closed space completely separated from the external space. It is due to this spatial structure that we cannot escape from the black hole and cannot communicate with the outside world.
In addition, since the cosmic nucleus exists at an equal distance in all directions, its gravity is canceled and becomes weightless, and the observer B falling there becomes inertial motion (uniform motion) instead of accelerated motion.
This starts when the Schwarzschild radius is exceeded. In this case, the fall observer B's fall energy does not increase and it descends the gravitational gradient of the central nucleus A, and finally collides with the central nucleus A. It is not common knowledge that the fall energy does not increase even if it descends the gravitational gradient, but this interpretation avoids the contradiction that the falling object gains infinite fall energy, and the law of conservation of mass and energy is observed. Moreover, the problem that a singular point is generated by infinite compression can be avoided.
An event horizon is formed between the core A and the falling observer B. The event horizon seen from B is the place where the light energy emitted there reaches zero and reaches B. It is also the place where the redshift becomes infinite.
Since the distances between A and B are equal in all directions, the distances to the event horizon are also equal. In other words, when viewed from the observer B, the event horizon exists at equal distances in all directions. This would appear to observer B as if the entire sky was enveloped in a dark, absolute zero temperature event horizon, with B floating in the center. This is a true representation of our situation in the real universe.