There are now theories that the universe began with a Big Bang . After the Big Bang, the universe went through stages of accelerated expansion, decelerated expansion, and then accelerated expansion. What is driving the accelerated expansion of the universe into ? What will be the future fate of the universe? Let’s see what Zhao Gongbo, a researcher at the National Astronomical Observatory of the Chinese Academy of Sciences, said ~
The universe is accelerating. In fact, this research started very early, but the first time it was confirmed experimentally was in 1998.
The history of the evolution of the universe that we understand today can basically be divided into three parts. The first is the beginning of the universe. At this stage, the expansion of the universe is very rapid. It is an accelerated expansion process, just like a person growing very rapidly in the infant stage. , from a baby to a giant baby in a short period of time. During this period, heavy elements had not yet been formed, such as elementary particles, photons, and electrons. This stage is very important. In fact, it is the seed of the evolution of the universe. The original disturbance was formed from that time.
The second is the intermediate process. During this process, the universe is growing and developing, slowly starting to form heavy elements, forming cosmic dust, forming the first generation of stars, and then galaxies. Scientists know more about this stage, which is decelerating expansion. Because of universal gravitation, matter in the universe attracts each other. Under this effect, the universe slowly expands, and the structure of the universe slowly grows, just like a sapling.
But in the third stage, that is, 6 billion years ago, the expansion of the universe began to accelerate again for unknown reasons, and it grew explosively. Scientists still don't know the reason. Some scientists believe that this is due to the existence of dark energy , but some scientists disagree because so far, we do not know what dark energy is.
We always say that there are two dark clouds in the sky of physics in the 21st century, namely dark matter and dark energy. These two things that account for 95% of the energy in the universe are completely unknown. The current basic theory of the universe believes that the role of dark energy is to promote the accelerated expansion of the universe; dark matter is a fundamental factor in the formation of structural galaxies. Without dark matter, these galaxies may not be able to form. The basic theory of
was proposed very early. Peebles, who won the Nobel Prize this year, proposed these so-called standards very early. But what the physical nature of these things is we don’t know. If dark matter is considered to be a particle, we have not found this particle today. No matter it is found in the accelerator or various experiments, it is not found. Dark energy is even harder to find because it is an effect on a macroscopic cosmological scale. Its corresponding energy density, if any, is very low.
Today we are lucky to have a variety of observational and experimental methods to help us. Through these observations and experiments, its properties can be slowly studied and its essence can be revealed. Maybe we don't know why the universe expands , but we may know, either why or by elimination.
We cannot predict the future. But by studying the past, we see signs of dynamics in energy today. If it is really dynamic, the fate of our universe may be cyclical, expanding and contracting and then expanding again, or it may continue to expand and eventually fall apart, or it may finally collapse to a point, all are possible. Therefore, the fate of the future universe depends entirely on the nature of dark energy. (Reporters Song Yajuan Xiao Chunfang)
