In the vastness of the universe, astronomers frequently mention a fascinating and mysterious concept – black holes. However, this does not refer to the dark void as we understand it in our daily lives, but rather a special area of the universe, an ultimate trap from which all matter and light cannot escape.
The concept of black holes is not new. As early as 1789, the French mathematician Laplace proposed a conjecture about black holes. He imagined that when the density or mass of a celestial body reaches a certain limit, it will become unobservable because light cannot escape its surface and reach our line of sight. This prediction was confirmed by Einstein's general theory of relativity at the beginning of the 20th century, and immediately attracted a lot of attention from the scientific community.
In 1965, astronomers detected intense X-rays from the constellation Cygnus X-1, which became an important clue for humans to detect black holes. After intensive study, the ray was confirmed to originate from an object with a mass of up to 5 to 8 times the mass of the Sun, although we could not see its position directly. To this day, Cygnus X-1 is still considered the most ideal candidate for a black hole.
Scientists have come up with a variety of theories about the origin of black holes. One view is that black holes are closely related to the birth and death of cosmic units. The universe originated as a massive "primordial black hole" that constantly devoured interstellar matter, triggering the Big Bang when density and mass reached their limits. In this big bang, part of the ultra-dense material did not immediately expand, but formed "black hole fragments". These fragments later became centers on their own, attracting newly formed interstellar matter, gradually forming galaxies and star clusters. The core of a large galaxy like the Milky Way may be a giant black hole.
In addition, when stars in the universe run out of nuclear fuel, they begin to collapse under their own gravitational pull. If the mass of the collapsing star is more than 3 times that of the Sun, then its final product will be a black hole. These black holes continue to devour the matter around them, increasing in mass. At the same time, the giant black hole in the center of the galaxy also comes into play, gradually absorbing the stars and small black holes in the galaxy. They snowball through the universe and grow stronger.
New discoveries by astronomers provide strong support for these theories. For example, the discovery of the "Hubble Stream" in 1986 showed that the Milky Way and thousands of other galaxies were being attracted to a huge group of matter. This group of matter, known as the "Great Attractor", is 300 million light-years in diameter and has a mass equivalent to more than 10,000 times that of the Milky Way. Although we don't yet know the exact nature of the large attractor, scientists speculate that it may be related to black holes.
In addition to black holes, general relativity also predicts the existence of "white holes". In contrast to black holes, white holes allow matter to escape from them, but external matter cannot enter. There has been speculation that black holes may form white holes after exploding, and that the nucleons of some quasars we observe in the universe may be white holes.
What secrets are hidden in black holes and white holes, the mysterious messengers of these two universes? Where are they? We have reason to believe that in the 21st century, an era of rapid technological development, these mysteries will eventually be revealed.