13.8 billion years ago, a mysterious singularity exploded, and the universe was born. After the birth of the universe is not a completely empty space, but a space full of all kinds of materials, these materials continue to evolve later, forming planets, planets and other celestial bodies.
We can directly observe all kinds of objects formed by matter. Even for mysterious and complex objects such as black holes, we can still determine their existence by observing accretion disks. For a long time in the past, human beings have always thought that the world and the universe are all visible matter, that is, matter that can be observed by us.
However, with the rapid development of human science and technology, especially after the deepening of space exploration, some scientists put forward a bold conjecture that there may be another invisible matter in the universe, which is called dark matter by scientists.
Dark matter is a kind of invisible matter that may exist in the universe theoretically. It was astronomer Kaptan who first proposed the possibility of dark matter. In 1922, he proposed that the possible invisible matter around a star can be inferred indirectly from the motion of the star system. The proposal of dark matter is a great conjecture in the history of science, and its influence is no less than that of relativity. At first, people didn’t believe that there would be this kind of invisible matter in the universe.
However, with the continuous deepening of scientists’ observation of the universe, many abnormal phenomena have been found, which can not be explained by visible matter. At this time, people think of the conjectured dark matter. Only after the introduction of dark matter, which is invisible matter, can many abnormal cosmic phenomena be fully explained.
So at this time, many people have believed that dark matter exists. Although we have not really observed dark matter directly until now, there has been a lot of evidence that dark matter exists in the universe. Since dark matter is a kind of invisible matter, which is very mysterious, can we hope to see its true face in the future?
First of all, we need to understand how scientists determine that dark matter exists in the universe in large quantities. Modern science and technology all draw conclusions about the existence of dark matter by observing cosmic phenomena. There are three main observational evidences to prove the existence of dark matter.
1、 Galaxy rotation curve and dispersion velocity distribution. The galaxy rotation curve describes the relationship between the velocity of the visible objects in the spiral galaxy and the distance from the center of the galaxy. According to the observation of the mass distribution of visible celestial bodies in spiral galaxies and the calculation of the law of universal gravitation, the velocity of the outer celestial bodies rotating around the center of the galaxy should be slower than that of the central celestial bodies
. However, the measurement of the rotation curves of a large number of spiral galaxies shows that the speed of the outer objects is almost the same as that of the inner objects, which is much higher than expected. This suggests that there is massive invisible matter in these galaxies.
2、 The mass distribution of galaxy clusters can be obtained by three different means: (1) observing the motion of the galaxies in the cluster and calculating it by gravity theory. (2) Observe the X-rays produced by galaxy clusters. Hot gas that can emit X-rays is ubiquitous in galaxy clusters. When the gas reaches hydrodynamic equilibrium in the gravitational field of galaxy clusters, the mass distribution of galaxy clusters can be inferred from its temperature. (3) Gravitational lensing effect.
According to general relativity, light from behind a cluster bends as it passes through a massive cluster, similar to a lens in optics. According to the bending degree of the background light, the distribution of matter in the cluster can be calculated. These three methods do not affect each other and support each other, which makes galaxy cluster observation an important means to study dark matter. These observations show that the total mass of matter in the cluster far exceeds the total mass of visible matter, and the extra mass is the mass of dark matter.
3、 Cosmic microwave background radiation, on the cosmic scale, the total amount of dark matter in the universe can be determined by fine observation of the anisotropy of microwave background radiation in the universe. Observations show that 26.8% of the total energy of the universe is contributed by dark matter, and only 4.9% of the conventional matter that makes up celestial bodies and interstellar gases. The remaining 68.3% is the dark energy that promotes the accelerated expansion of the universe.
Through these observations, scientists confirmed the existence of dark matter, and its mass is much higher than that of visible matter. If we add dark energy, more than 85% of the matter in the universe may be composed of dark matter and dark energy, and the visible matter that can be observed in our eyes only accounts for a small part of the total mass of the universe.
The discovery of dark matter and dark energy is of great significance for human beings to study and explore the universe. So can such matter be observed by us in the future? The answer is yes. As long as matter exists in this universe, it will escape from the scope of science. The essence of dark matter still belongs to science, but we don’t know its essence at present. Once we know the essence of dark matter, we can make it appear in front of us.
So what will dark matter do for humans? Many people may think that although dark matter is the majority in the universe, it is not very useful for human beings. Our survival and development mainly depend on visible matter. Is that really the case? Of course not. As long as we know that dark matter and dark energy are dominant in the universe, it means that dark matter is a very important matter for the universe.
Some scientists speculate that the essence of the universe may be dominated by dark matter and dark energy. After the big bang, the universe expanded rapidly, and the core participants may be dark matter and dark energy. Dark matter constructs the framework of the universe, while dark energy promotes the expansion of the universe. Another expectation of scientists for dark matter and dark energy is to realize interstellar navigation through them and solve the ultimate mystery of the universe.
We all know that we can’t explore the universe without the advantage of speed. The distance of the universe is based on light years, and Einstein’s theory of relativity limits the limit speed of an object to the speed of light.
If the upper limit of the speed of an object is the speed of light, it is impossible for us to explore the whole universe, or go out of the galaxy. However, the vast existence of the universe is an indisputable fact. Since it exists, there must be a speed that can travel through the universe, which is far faster than the speed of light and the expansion of the universe.
So how to achieve this speed? Scientists think of space distortion. Only the wave generated by space distortion can drive the spacecraft to fly faster than light. Although the distortion of space is caused by gravity on the surface, scientists believe that dark matter and dark power are the real dominators behind it.
If we can master dark matter and dark energy, we will also master the laws of cosmic space. At that time, we can use the power of dark matter and dark energy to shuttle through different stars and realize the dream of traveling all over the universe.
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