The birth of a black hole is accompanied by the end of a giant star or the collision of fragments of stars, as described by space scientist/Isaac Newton/Stephen Hawking, in the dark realm of the event horizon, which is proportional to its mass, is the expansion of a never-ending accretion disk of matter. In the vastness of the universe, gravity and time work completely differently than we usually imagine, so let's take a look and see how this cosmic journey will end.

First of all, what exactly is the secret inside a black hole?

How does gravity act on us? Why does it exist?

Let's start at the beginning to make sure we can reveal the answers to all our questions.

First of all, we need to realize that as long as we exist in this universe and are not affected by external forces, we are all "free". I am not referring to freedom in the sense of law or human rights, but freedom from any external force. Imagine yourself as an astronaut floating in space: without the support of the ground, without the friction of air molecules, without chairs to lean on, and without contact with others, we are free in the universe. Although we don't usually think that way, it also means that we are at the mercy of gravity.

Of course, although we may not feel it, gravity is always pulling us. Would you think that the force we feel on the surface of the earth is gravity? Not really. What we feel is a force that has been balanced with gravity, such as a chair, the ground, or any plane that supports our body. When we ignore these forces, gravity is like a momentary feeling of weightlessness in free fall, or it can be described as a state of being only affected by gravity.

However, in every corner of the universe, there are objects of quality (masses); This is true of the earth and the sun, and this is true of every planet and nebula in the universe. Using our imagination, the universe is not a flat grid, but is distorted by the presence of masses. Our journey through the universe will be determined by the distorted space.

The originally flat three-dimensional space is bent by the mass distribution. According to the general theory of relativity, we consider space and time to be continuous, containing not only mass, but all forms of energy cause the curvature of space-time.

Gravity is the curvature of space due to the presence of mass (and energy) and its effect on other objects (such as us) that exist in that space. This concept is not set in stone. As the mass moves in space, the structure of the space changes. As the Earth revolves around the Sun, the degree of distortion in space changes. As the Sun moves around the Milky Way, the curvature of space also changes. As stars are generated, active, exploding, and dying, the structure of space is constantly changing.

It's part of the cosmic dance and part of the gravity story. The structure of space is constantly changing along with a series of movements that occur in the universe, such as the movement and change of mass, and the expansion of the universe. Gravity is always real, as if we are in free fall, constantly pulling everyone.

If we move from the right position at the right speed and direction, we can form a stable orbit around any mass in the universe. But if we're not careful, we'll fall into the mass we're trying to wrap around. The rocket does not launch fast enough and will fall back to Earth. If you reduce the orbital speed of the planet, it will fall towards the sun. And by slowing down a star orbiting it, it crashes into the center of the galaxy. In extreme cases, if our orbital motion is off, we may be sucked into a black hole. A black hole is the ultimate in mass: a black hole with enormous density, infinite mass, and compact volume, from which it cannot escape once entered. Even the speed of light, the limit of cosmic speed, cannot be escaped.

Beyond the event horizon of a black hole is an extremely distorted space-time. The closer we get to the mass, the more distorted the space becomes, eventually creating an area from which even light cannot escape, which is the event horizon.

As we approach the event horizon of a black hole, we experience some perverse events, and once we cross it, the situation only gets worse. Therefore, once we break through that invisible barrier, we will never be able to escape.

When you move away from a black hole, the structure of space is less distorted. In fact, when moving away from a black hole, its gravitational pull is no different from that of any other mass, whether compared to a neutron star, an ordinary star, or a gas cloud. From a distance, we can only speculate that the existence of the mass, rather than its properties or distribution, causes the distortion of space-time. Whatever is used to replace the position of the black hole, we will do free fall. But it looks different than it did when black holes existed.

What is the outline of a black hole against the backdrop of the Milky Way? The event horizon is an area of darkness from which no light can escape.

As our distance from the black hole shortens, we will feel a force pulling at our body. If our feet are closer to the event horizon than our heads, we will feel a stretch from head to toe and the sides of our body will be compressed. These are tidal forces, the forces that cause the Earth's oceans to rise to the tide. It's just that the tidal forces at the black hole are much stronger, and the closer we get, the more severe the tension and compression caused by the tidal forces. It pulls us thin and long until we become a spaghetti stick. Scientists use a very interesting word to describe what happens when an object falls into a black hole – spaghetti!

Even if we start out as a perfect sphere, we are elongated and compressed in a direction perpendicular to it as we move towards the black hole. The force in the center of the object will be comparable to the equilibrium force, while different points away from the center will experience different forces. This is the result of "spaghetti".

We will witness a wonderful show. From a distance, we only notice the spatial distortion around it, as if this mass provides a massive cosmic lens that distorts all the light around it. But as we travel heavily armed and in a sturdy spaceship, we will witness some strange phenomena as we get closer to the black hole. When we halve the distance from the black hole, its angular diameter appears to increase by more than two times. When we halved the distance again, the angular diameter became larger again: it became more than four times the original one.

Unlike other objects we know about, space has an incredible curvature, and this incredible curvature of space-time makes black holes seem to grow much faster than we expected.

Under general relativity, forces can stretch and distort space, and light from behind a black hole bends around it, leaving behind a huge dark disk that echoes the black hole's event horizon.

In short, mass distorts space-time, but as we get closer to an extremely massive object, such as a black hole, the curvature of space increases, the more tidal forces and the "spaghetti" effect becomes more pronounced in us, and the light emitted around the black hole bends further. Compared to the actual physical size, the event horizon appears much larger. In the cosmic context, the positions of distant stars are violently distorted, and the event horizon will begin to dominate our full field of vision.

When we fall into a black hole or simply approach the event horizon, its size and scale appear much larger than it actually is. For an outside observer, when we enter a black hole, our information is imprinted on the event horizon. It's unclear what the outcome of this information will be as the black hole evaporates.

As we get closer and closer to the event horizon, it seems to fill everything in front of our eyes. Once we cross that line, our fate is sealed. Aside from the singularity in the center, there isn't much energy left to allow us to move elsewhere. At the singularity, we are crushed into subatomic particles in a matter of seconds.

No, we can still be saved!

As long as we haven't crossed the horizon of events, we still have a chance to escape. As long as we provide enough acceleration and move away from the event horizon, we can escape the gravitational pull of the black hole and return to the safety of the universe, away from the black hole, back to that near-flat space-time. Gravitational sensors will tell us that there is a clear descending gradient in the direction of the dark center, while in the opposite direction, the starlight is still brilliant.

This scenario is almost certain to happen; As we are swallowed by a black hole, the brilliance of the stars will take on a strange color. The plasticity of gravity on space-time is further intensified, causing the radiation waves falling on the retina to speed up, resulting in a more vivid blue color. If you get closer to the boundary of the event horizon, you will witness the starlight converging into a tiny dot in your field of vision and gradually turning into a deep blue as gravity shifts red. The moment it touched the event horizon, the color of the point of light changed from red to purple and then from purple to white. This is the last thing we see before we fall into a black hole, where the microwave background of the universe and the radiation in the radio band are converted into light visible to our naked eyes.

And then...... It was dark, it was empty. Behind the event horizon, all light from the universe is blocked from reaching our ship. Trying to start the engine of the flying machine is futile, and no matter how much you struggle, you can't change your doomed fate. What we see is an illusion: no matter where we go, the singularity seems to be waiting before our eyes.

This extremely distorted plane is so strange that we can't actually see the singularity. In fact, the surrounding light is swallowed by the black hole with us, passing through the event horizon in front of us, maintaining a looming relationship with us.

From the moment we cross the event horizon of a black hole, we can be compressed into tiny pieces in just a few seconds. But in the largest black holes, there may be passages to other regions: a white hole, another universe, or a new world that we cannot imagine, obscured by the event horizon. At the moment, we can't get any information from external black holes, and we can only rely on scientific theories.

Still, it's best not to fantasize about falling into a black hole, because the most likely outcome is to be torn to pieces or compressed to the extreme. However, if you do enter a black hole, you will be the only one who can reveal its true face, the first explorer to uncover the secrets of the black hole. However, this kind of thing may not be what you expect, and this avoidance may be a wise decision. But in this vast universe, if we aspire to be the first to uncover the unknown, we must be brave enough to take the risk of exploration.