Black holes are terrible for three reasons. If you fall into a black hole when a star dies, you will be torn to pieces. Similarly, the huge black holes seen in the center of all galaxies have a good appetite. Black holes are places where the laws of physics are eliminated.
Many people pay attention to supermassive black holes lurking in the center of galaxies. In most cases, they are inactive, but when they are active and devour stars and gases, the area near the black hole will be more dazzling than the whole galaxy that houses them. Galaxies with active black holes are called quasars. In the past decades, we have learned all about black holes, but there are still many unsolved mysteries.
Black hole death When a huge star dies, it is expected to form a black hole. After the nuclear fuel of a star is exhausted, its core collapses to the densest material state imaginable, and its density is 100 times that of the nucleus. The density is so great that protons, neutrons and electrons are no longer discrete particles. Because black holes are dark, they will be found when they orbit normal stars. The characteristics of normal stars enable astronomers to infer the characteristics of their dark companion stars (black holes).
The first black hole discovered is Cygnus X- 1, which is the brightest X-ray source in Cygnus. Since then, about 50 black holes have been discovered in the system where normal stars orbit around black holes. It is estimated that there are about 654.38+0 billion black holes in our galaxy.
Black holes are the graves of matter. Nothing can escape them, even light. The fate of people who fall into black holes will be painful "spaghetti", which is explained in Hawking's book A Brief History of Time. In the process of spaghetti, the huge gravity of the black hole will pull you away and separate your bones, muscles, bones and even DNA molecules. As the poet Dante described in his poem Divine Comedy: All those who enter here, give up hope.
Every galaxy has hungry beasts. In the past 30 years, observations by the Hubble Space Telescope show that there are black holes in the centers of all galaxies. The bigger the galaxy, the bigger the black hole.
Nature knows how to make black holes in a huge mass range, from stars several times the mass of the sun to monsters tens of billions of times the mass. Just like the difference between Apple and great pyramid of giza.
Just last year, astronomers released the first picture of a black hole and its event horizon, a beast whose mass is 7 billion times that of the central sun of the M87 elliptical galaxy.
It is 1000 times larger than the black hole in our galaxy, and its discoverer won this year's Nobel Prize. These black holes are dark most of the time, but when their gravity attracts nearby stars and gases, they will burst into violent activities and emit a lot of radiation. A large number of black holes have two dangers. If the distance is too close, great gravity will attract you. If they are in an active quasar stage, they will be blown up by high-energy radiation.
Quasars have how bright? Imagine hovering over a big city like Shanghai at night. Cars, houses and streets in the city emit about 65,438+billion lights, corresponding to the stars in the Milky Way. For example, an active black hole is like a light source with a diameter of 2.54 cm in Shanghai, which is hundreds or thousands of times higher than the city. Quasars are the brightest objects in the universe.
Supermassive black holes are strange. So far, the largest black hole discovered is 40 billion times the mass of the sun and 20 times the volume of the solar system. The outer planets of the solar system rotate once every 250 years, while the more massive celestial bodies rotate once every three months. Its outer edge moves at half the speed of light. Like all black holes, big black holes are blocked by events. Their center is a singularity, which is a space point with infinite density. We can't understand the inside of a black hole because the laws of physics have failed. Time freezes at the event horizon, while gravity becomes infinite at the singularity.
The good news about many black holes is that you may fall into them. Although their gravity is very strong, their pull is weaker than that with small black holes and won't kill you. The bad news is that the scope of the event marks the edge of the abyss. Nothing can escape from the horizon, so you can't come back and report your experience.
Hawking thinks that black holes are slowly evaporating. In the distant future of the universe, with the accelerated expansion of the universe, black holes will be the last surviving celestial bodies after all the stars die and the Milky Way darkens.
The maximum black hole evaporation takes countless billions of years, which is estimated to be 10 to the power of 100 (or 1 00 zeros behind1). The scariest object in the universe is almost eternal.