Since ancient times, countless people like to look up at the stars at night. Looking at the countless stars appearing in the night sky, many people in ancient times would think: what are they?
Due to the lack of scientific knowledge, the ancients knew nothing about the world outside the earth, so they were full of mysterious curiosity about the sun, the moon and countless stars, so there were all kinds of myths and legends about stars.
When human beings enter the road of scientific development, in the palace of science, we know that there is more vast space beyond the earth, and the stars we can see at night are basically stars very far away from us.
Those stars in the sky are basically stars similar to the sun. If you tell people in ancient times, few people will believe it. It is difficult for the ancient people to connect the terrible burning sun with those stars. In the eyes of the ancient people, the sun is supreme, bringing light, temperature and hope to the world. However, those stars are much weaker and have no comparability with the sun.
But now with the scientific vision, we all know that the sun is insignificant relative to those stars in the sky. Many stars are far beyond the sun. For example, uy, the largest known star, can orbit near Jupiter if it replaces the sun.
The universe is vast and vast, stars are the most important kind of celestial bodies in the universe, and also a kind of universal celestial bodies. Stars rely on their own mass advantage to form a stellar system, and a large number of stellar systems form a larger galaxy. For example, the Milky way, is it big? At the solar system’s point of view, the Milky way with a diameter of 100000 light-years contains about 150-400 billion stars.
The solar system is a grain of dust in front of the Milky way, so how many galaxies are there in the universe? The current data may be despairing. To figure out how many galaxies there are in the universe, we need to analyze and count them one by one.
The Milky way is a huge galaxy in front of the solar system, but when you walk out of the Milky way, you will find that it is nothing at all. There are many large galaxies around the Milky way, such as Andromeda galaxy, which is 2.54 million light-years away from us. Its diameter is 220000 light-years, much larger than the Milky way, and contains about 100 billion stars.
In addition to Andromeda, the Milky way has three neighbors: the Large Magellanic galaxy, which is 163000 light-years away from the Milky way, the Small Magellanic galaxy, which is 210000 light-years away from the Milky way, and the triangularis galaxy, which is 3 million light-years away from the Milky way.
A large galaxy such as the Milky way is the basic system unit of the universe. It is a huge system composed of many stars, gases, cosmic dust and various substances under the action of gravity. If the universe is compared to a vast ocean, then the galaxies are equivalent to islands in the ocean.
Many cosmic islands will form a larger structure and system under the action of stronger gravity. For example, the Milky way and about 50 surrounding galaxies together form a galaxy group, which we call the local Galaxy Group. The diameter of the cluster is about 10 million light-years, 100 times the diameter of the Milky way.
Together with other galaxy cluster structures, our galaxy forms a larger cosmic structure, which we call the Virgo supercluster. It contains about 2500 galaxies with a diameter of about 65 million light-years. Outside the Virgo supercluster is the larger Virgo supercluster, which includes at least 100 clusters and clusters, with a diameter of about 220 million light-years.
So is the Virgo supersystem big? Of course not. There are larger systems on top of it, which we call the Rania Kea supercluster. This is a cosmic system spanning 520 million light-years, including about 100000 galaxies, including Virgo supercluster, Hydra cluster and Centaurus cluster.
There are many superstructures in the universe, such as the Rania Kea supercluster, which together with other nearby superclusters form a huge cosmic fibrous structure. These fibrous structures of cosmic superclusters are like a big net. At the center of the net is the void of the universe, where there is nothing.
This fibrous cosmic superstructure, also known as the Great Wall, is 500 million light-years long, 300 million light-years wide and 15 million light-years thick. And the countless tiny sands that make up the great wall are big galaxies like the Milky way.
The vast structure of the universe is an eye opener, but when we look further, you will find that this fibrous large-scale structure is nothing. It’s just a speck of dust in the observable universe of 92 billion light-years. At present, scientists can observe about 125 billion galaxies.
Some people may say that this number is within the acceptable range, but in fact, it is only an observation data under the current human science and technology. With the continuous progress of human science and technology and the continuous improvement of observation technology, this number will continue to grow in the future. Even in the large-scale cosmic holes we have observed, there are not no galaxies, but they are relatively rare, which cannot be found with the current observation ability of human beings.
In addition to the observable universe, there is also an unobservable universe, which may be a more vast area. Because the speed of light is fixed, only the speed of light, and the expansion of the universe is faster than the speed of light, the greater the distance between galaxies, the faster the distance will be. When the distance reaches a certain level, the speed of the galaxy away from us will exceed the speed of light. In the space outside the galaxy, the speed of photons is less than the expansion speed of the universe, and we will never reach the earth, and we will not be able to observe the space outside the galaxy.
It can be seen that the number of galaxies that may exist outside the observable universe is even larger. It is impossible to observe the Galactic space beyond the superluminal expansion with the current human observation technology. Only when we develop more powerful detection equipment in the future will it be possible to observe the whole space regardless of the distance. At that time, the number of galaxies in the universe might make us despair.