The current state of the universe
Astronomers believe that time, space and matter emerged as a result of a simultaneous event: the explosion of something hot and very dense, the so-called big explosion that occurred 10-20 billion years ago. According to modern notions, the Universe we observe now appeared 13.7 ± 0.2 billion years ago from some initial “singular” state with infinite temperature and density, and since then it has been continuously expanding and cooling. The early Universe was a homogeneous and isotropic medium with an unusually high energy density, temperature, and pressure. As a result of expansion and cooling, the Universe has undergone phase transitions similar to the condensation of liquid from gas, in relation to elementary particles.
The expansion of the universe occurred with incredible speed. In the first millionths of a second, the most important processes took place. The smallest particles are quarks and electrons, which, when combined, turned into atoms and molecules. The first substances appear, the main of which is hydrogen. These “bricks” form our universe.
In our time, it was found, apparently, that our universe is expanding, and with acceleration. This fact does not abolish the Hubble Law, as the latter is more closely related than these new effects. Since Hubble's constant itself and many other cosmological values are determined with a very large error, it is still not clear whether the universe will expand faster and faster, or, conversely, with deceleration. In this regard, there are very different scenarios for the possible development of the universe in the future. According to one of them, the universe may even begin to shrink to a point during the so-called “big collapse,” a process inverse to the big bang. Theoretical physics takes seriously enough the hypothesis that the current state and thin structure of the vacuum are the so-called “false” or “imaginary” vacuum. This state is unstable and can pass to the “true vacuum” with less energy. Then our Universe will be lost in an instant and irreversibly. However, the theories of the “thermal death of the universe” pay the greatest attention now. In the expanding Universe, temperatures will be gradually balanced, which will become the same at all points in space. Stars moving away from each other, where thermonuclear processes will end, will cool down, and more and more energy will be in the form of radiation. Even black holes will slowly “evaporate” due to quantum tunnel effects. Such a scenario is in full harmony with the concepts of classical thermodynamics.
There is a version that the force of mutual attraction will someday stop the process of expansion, because of which, the galaxies will begin to fall on each other, which will eventually lead to a “big compression”. However, this question remains controversial because it is still not clear whether our universe is closed.
Later on, cosmology gets a big leap in its development in the second half of the XX century. Entire research institutes, galaxies of scientists, as well as the first cosmonauts appear..., which is connected, first of all, with the scientific and technical progress and the accumulated knowledge about space from the previous generations of scientists. And this, of course, is also connected with the ongoing “cold war between the USSR and the USA”. The first spacecraft and satellites appear..., and competition for space is growing.
Nowadays, space research is one of the most promising and prestigious scientific fields, which is in great demand in many countries. The development of this scientific sector is one of the most significant indicators of how well the state is developing. Russia takes part in space exploration.
First of all, it is necessary to give a clear scientific definition of space. Cosmos (Greek: к) — in materialistic philosophy — is an ordered universe (as opposed to chaos). Later the concept of space became identical to the concept of the Universe. In turn, the Universe is usually defined as the totality of everything that exists physically. It is a totality of space and time, all forms of matter, physical laws and constants that govern them. However, the term Universe can be interpreted differently as space, world or nature.