How to describe a mysterious black hole scientifically
When many people talk about black holes, the first thing that comes to mind is its infinite curvature and infinite singularity heat. Simply put, a black hole is just the limit of gravity, just like a very large collection of matter occupying a small space. But in fact, there is not only one way to describe black holes. For example, we can simply define it as an object whose density is so high that light cannot escape from the surface.
At the same time, we can also describe how fast an object needs to break away from the gravity of another object, which is the so-called escape velocity. If an object wants to get rid of the gravity of another object, it must reach this escape velocity. The escape speed depends on two main factors, one is the mass of the target object itself, and the other is the distance from the center of the object.
We can take the well-known rocket as an example: when the rocket wants to avoid the gravity brought by the earth, it must accelerate to the speed of 1 1.2 km per second. However, if the rocket is on a planet with a radius only half that of the earth, it needs to have an escape speed of 15.8km per second. Moreover, even two planets with the same mass have different densities and sizes, so their escape speeds will be correspondingly larger.
What are the structural characteristics of invisible black holes?
Black holes have two basic components, which are called horizons and singularities by scientists. The horizon refers not to the physical surface in the ordinary sense, but to the sphere around the black hole. Its radius is schwarzschild radius, which marks the position where the escape speed and the speed of light are equal. Events that enter the interior will eventually fall in the center, and matter will have infinite density after being compressed to a small volume.
Since even light can't escape the gravity of black holes in such a special space, how do scientists observe black holes? In fact, so far, all scientists' research on black holes is not based on direct observation, but on its impact on the surrounding environment to confirm whether it exists and its size. In short, the study of black holes depends largely on indirect detection.
Although we can't see the black hole and its internal activities, we can observe the behaviors of the objects around it, which are related to the nearby dense objects (black holes). Moreover, the black hole may have an impact on the surrounding objects, including but not limited to the matter being pulled into the black hole, thus forming an accretion disk that rotates around a huge but invisible object.
What does it mean for humans to live near black holes?
For supermassive black holes, because they are always at the center of galaxies, there are stars of different sizes around them. Therefore, if we live near such a black hole, we don't need to use tools such as electric lights for lighting, no matter day or night. Maybe you think this experience is really cool, but in fact, when you live too close to the black hole, the black hole will concentrate and amplify the light emitted by the surrounding stars, and these super light may release terrible radiation.
If we live around black holes and want to study the sun in more detail, it will be more challenging than when we are on earth. Because, the primary problem we face is how the satellite can withstand such extreme space weather. In such a special space, if the spacecraft wants to communicate with the planet where we live, it will face great problems in the timeliness of message transmission, and it is easy to have a certain degree of time delay. For example, the reason why humans didn't land on Mars is because the earth may face a delay of about 22 minutes when communicating with it.
Because the objects near the black hole will experience different time modes, the degree of time delay will be aggravated, and the real speed of things will be faster than we seem. In short, the satellite communication launched in the direction of the black hole will have a longer delay because of the shorter distance. Maybe when we received the information from the satellite, it had disappeared without a trace. Moreover, neutrinos in clusters near black holes will also radioactive heat objects in close contact with them.
The released radioactive heat not only illuminates the surrounding space, but also heats the adjacent space. Neutrinos are tiny and fast particles, which have almost no weight and will not interact with any other matter, but because they are large enough and located near black holes, they can heat all the objects they hit. Simply put, the planet will heat the core after absorbing neutrinos. To sum up, if we live on a planet near a black hole, we will face more problems and life problems, which is probably why our earth is not located in such a special area.