There are many galaxies in the universe, and these galaxies are listed in the universe and combined into a mysterious and complex network of cosmic structures, how these galaxies developed, and what kind of evolution process is behind the different structures of galaxies.
The structure of galaxies
The structure of galaxies is a complex and diverse system, it has many hierarchical compositions, scientists have found through its observation and research, the structure between galaxies and galaxies is roughly divided into galactic nucleus, galactic disk, galaxies, halos, intergalactic medium and satellite galaxies.
The galactic nucleus is located in the most central and densely populated region of the galaxy, through the development of a large number of old stars, as well as star clusters and so on.
And the nature of the galactic nucleus is also different, they will also vary according to the type of galaxy in which they are located, the galactic nucleus in the elliptical galaxy is usually relatively dense, and for the galactic nucleus in the spiral galaxy, it may contain a huge black hole.
Around the core of the galaxy, there is a galaxy disk that gradually extends out, and there are relatively young stars in it, and there is also gas and dust in the galaxy disk.
In spiral galaxies, the disk will contain several spiral arms, in which there are many stars and gas clouds.
In the periphery of the galaxy disk, there is still a layer of sparse areas, which are also part of the galaxy, which is the galaxy halo, and in this area, there are a lot of dark matter and globular clusters, and the stars in the galaxy halo region are also older than the galaxy disk, and the density in these areas will be lower than that of the galaxy disk.
Between galaxies and galaxies, there is no complete vacuum in the universe, which is filled with thin gas and some cosmic dust, and the composition of these substances is the intergalactic medium between galaxies in the universe.
These gases are mainly composed of light elements such as hydrogen and helium, and these gases and dust are important intermediaries between galaxies for the exchange of matter and the transmission of energy.
Around the galaxy, there are also some satellite galaxies, and the smaller galaxies around the large galaxies are called satellite galaxies. The same galaxy evolved in the process of formation, and has an inseparable role with the main galaxy, and there is also a gravitational attraction to each other.
The evolution of galaxies
The formation of galaxies in this way can be described as a long and complex process, which involves many stages, and there are many reasons that affect their evolution.
In the beginning, according to the Big Bang theory, the universe began to expand dramatically after the Big Bang, and in the process of expansion, matter began to slowly gather in the process of mutual attraction, and with the accumulation of matter, the most primitive galaxies were gradually formed.
But at this time, galaxies were only composed of some gas and cosmic dust, and there were no stars at this time, and the appearance of stars was also after that.
As gas and dust do not accumulate chaotically, they collapse and collapse, which is also the key to the formation of stars, and the mass of dust and dust that continues to accumulate increases, and with the change of temperature, etc., the star is gradually formed.
With the formation of stars, some planets have also formed around them, and along with the interaction between gravity, stars and satellites have gradually become the main components of galaxies after millions or even billions of years.
After the formation of galaxies, they are not static, they will go through different stages of evolution over time, and galaxies and galaxies also have mutual gravitational attraction and interaction, which will also attract two galaxies to merge and influence each other.
The merged galaxy will also evolve into a new galaxy, and the structure of the galaxy will also change, which is why there are different structures between galaxies and galaxies.
The evolutionary cycle of galaxies
After the galaxy is fully formed, the continuous evolution also has a relative periodicity, and in the evolution process of the galaxy, scientists divide its evolution cycle into a dormant period, a chaotic period, a stable period and a final decay period.
At first, during the dormant period, the black holes in the galaxy were constantly absorbing the celestial bodies and other matter in the surrounding space, and then after the matter entered the black hole, it continued to increase the mass and energy of the black hole.
When the energy of the black hole exceeds a certain level, it will explode, and after the black hole explodes, the evolution of the galaxy will enter the chaotic period from the dormant period.
The chaotic phase of galaxies is also one of the most turbulent stages in the evolution of galaxies, and the stable structure and morphology of galaxies will change most significantly due to the Big Bang of black holes or the influence of other celestial bodies on galaxies.
And this stage will gradually stabilize under the interaction of gravity and other forces, and after the chaos lasts for a while, it will usher in the stabilization stage of the galaxy.
In the stabilization stage of galaxies, the internal structure and morphology of galaxies have tended to be relatively stable, and stars and other celestial bodies will move in the galaxy according to relative laws, and the galaxy at this time presents a stable dynamic equilibrium.
However, the stabilization period is not permanent, with the development of the stabilization period and the aging and change of stars and other celestial bodies, the evolution process of galaxies has also entered the final stage, the vitality of the galaxy begins to decline, the nebula will become thinner and thinner, and even the distribution of stars will change very much.
When galaxies completely deplete their internal energy and matter, they eventually collapse and disappear, which is the complete cycle of galaxy evolution that scientists have discovered today.