There are countless celestial bodies in the vast universe, and different celestial bodies have different qualities. In the universe, quality is king. Whoever has the highest mass and who is the boss will become the overlord of the starry sky. So among the many celestial bodies, which one can be called the overlord? Many people think of black holes.

Yes, the black hole is a well-deserved overlord of the universe. Its mass is so powerful that all celestial bodies are trembling. Some friends may say that the mass of a neutron star is similar to that of some small black holes. Why can the black hole still swallow the neutron star after the two meet?

An important reason for this is density. The mass of a neutron star is large, but its volume is also dozens of kilometers. Black holes are different. The black holes we observe seem to be very large. In fact, they are all its accretion disks. The real black hole is a singularity located in the center, and the mass is mainly concentrated here.

What is the singularity? It is a thing with the extreme mass and the extreme small size. Its density is so large that we can’t imagine it. Therefore, after any celestial body encounters a black hole, it is difficult to defeat a black hole, because its volume is infinitely small and its density is infinite. Who can defeat such a monster. Therefore, when a star encounters a black hole, it has only the fate of being swallowed. Perhaps only when a black hole meets a black hole can they swallow each other and merge.

Judging from our current understanding of the universe, black holes are undoubtedly the most powerful celestial body, and no one can fight against it. The most intuitive understanding of black holes is the supermassive black hole in the center of our galaxy-“Sagittarius A*”. Its mass is 4.3 million times the mass of the sun and its diameter can reach 44 million kilometers.

The gravitational force of such a big black hole firmly binds the Milky Way with a diameter of more than 100,000 light-years. Under its powerful gravitational force, the stars of the entire galaxy will orbit around it. We have already seen the power of this supermassive black hole, but we do not have an intuitive understanding of some very small black holes.

So a friend raised an interesting topic: How big is the mass of a black hole with a diameter of one centimeter? What would happen if it were close to the earth? A black hole with a diameter of one centimeter is naturally very small. Many people may think that such a small black hole has no power and cannot affect the earth. So is this really the case?

We evaluate the strength of a celestial body by mass and density. So how big is the mass of a black hole with a diameter of only one centimeter? As we said earlier, a black hole is not a hole. It is a sphere with an extremely small volume. On the periphery of this singularity is the horizon. The radius is called the “Schwarzschild radius.”

Through a formula V = 4/3πr^3 we can calculate that the “Schwarzschild radius” of this black hole is approximately 0.62 cm. Through calculation, we get the mass of this one-centimeter black hole, which is about 4.18 x 10^21 tons. Maybe many people don’t have an intuitive understanding of this quality, so we use a celestial body to compare with it, this celestial body is the earth’s neighbor Venus.

The mass of Venus is very close to that of the Earth, about 4.87 x 10^21 tons. From the data, we can see that the mass of a black hole with a diameter of one centimeter is equivalent to the mass of a Venus. Newton’s law of universal gravitation tells us that the magnitude of gravity is related to mass and distance, but not much to volume.

So let’s not look at this black hole being very small, only one centimeter in diameter, but the gravitational force it produces is comparable to that of Venus. Imagine what would happen if Venus were moved to the orbit of the earth? I believe many people can imagine that the earth’s material will be constantly torn apart, triggering a “tidal disintegration event.”

The impact of Venus’s approach to the earth is far less than the impact of the same mass black hole approaching the earth. The black hole is powerful because of its terrible swallowing power generated by its gravitational pull. The debris generated by Venus’s approach to the earth will be scattered in the nearby space, while the debris generated by the black hole’s approach to the earth will be continuously swallowed by it.

At that time we will see this scene: a small black hole approaches the earth, breaking the balance of the earth’s gravitational force. The surface of the earth closer to the black hole begins to be torn into pieces continuously, and the pieces fly along a spiral orbit. A black hole produces a disk-like structure around the black hole, which is the accretion disk of the black hole.

Most of the matter in the accretion disk will not be swallowed by the black hole immediately, but will rotate around the black hole at a high speed under the strong gravitational force of the black hole. During the high-speed rotation, violent collisions and frictions will occur between the fragments, and temperature It will also rise rapidly, and when it reaches a certain level, it will emit strong radiation.

This is also the reason why we can observe some massive black holes. What we see is not the true face of the black hole, but the accretion disk surrounding it. The process of the black hole disintegrating the earth is called a “tidal disintegration event”. Its duration is related to the mass of the black hole. If it is a relatively large black hole, the earth will soon be swallowed and disappeared.

But if it is a black hole with a diameter of only one centimeter, it will take a relatively long time to completely swallow the earth, and it will not immediately make the earth disappear. Although a small black hole cannot quickly swallow the earth, as long as it appears near the earth, the earth will be swallowed sooner or later.

This shows how terrible a black hole is, and it is difficult for any celestial body to escape. Fortunately, a black hole wants to appear in the solar system and it is also a very small probability event to appear next to the earth. Even so, we cannot guarantee that there will not be a small black hole around the earth in the future, and if the black hole is too small, we will not be able to observe it, because there is often no obvious accretion disk around the small black hole, and there will be no obvious emission. The light.

Some scientists speculate that the ninth largest planet that may exist in the solar system may be a primordial black hole. If this conjecture is confirmed in the future, it is not good news for the earth. The original black hole appeared early in the birth of the universe. It is a very small black hole with a mass equivalent to a planet.

If a black hole appears in a star system, even if it is small, it is a potentially huge threat. Of course, we are still unable to determine whether the ninth planet exists. If it exists, whether it is a planet or a small black hole needs further exploration.

The reason why we are afraid of black holes is mainly because we still know very little about it, so we can say that we don’t know much about it. We don’t know what a real black hole looks like except for the observable accretion disk.