How black holes are created

A black hole is a type of celestial body that exists in the universe in the modern theory of general relativity. The gravitational pull of a black hole is so strong that its escape velocity within the event horizon is greater than the speed of light, and it is an object with such a curvature of spacetime that light cannot escape its event horizon.

In 1916, German astronomers obtained the vacuum solution of Einstein's field equations by calculation. This solution shows that if the actual radius of a static spherically symmetric star is less than a fixed value, strange phenomena can occur around it. That is to say, there is an interface - the "horizon". Once you enter this interface, even light cannot escape. This fixed value is called the Schwarzschild radius, and this "incredible celestial body" was named "black hole" by American physicist John Archibald Wheeler. Black holes cannot be observed directly, but their existence and mass can be known indirectly, and their effects on other things can be observed. Information about the existence of a black hole can be obtained by releasing the "edge information" of X-rays and gamma rays, before the object is sucked in, due to the frictional force generated by the acceleration brought about by the gravity of the black hole.

At 21:00 on April 10, 2019, the first black hole photo was released. This black hole is at the center of a massive elliptical galaxy in the constellation Virgo, 55 million light-years from Earth. On August 24, 2022, NASA released an audio clip composed of pressure waves from the Perseus black hole 200 million light-years away.