In our universe, everything we can touch, see, smell or feel it's only 5% of everything that exists. The matter that we are used to dealing with and seeing is quite rare in the universe.
If we only know 5%, what happens to the rest? The evidence suggests that 27% of the mass and energy of the universe is made up of the so-called dark matter. Although dark matter remains a true mystery today, what do we know about dark matter? What is it for?
Dark matter
Our universe is made up of matter and energy. We are used to dealing with matter at all hours of the day. A computer, our smartphone, a table, etc. They are composed of ordinary matter. However, our universe not entirely composed of ordinary matter, but dark matter.
This dark matter cannot be seen with the naked eye, but it is what gives the entire universe the dynamics. Dark matter can't be seen because it is in the deepest space and it is very cold. To observe the celestial bodies from this small planet what is done is to detect radiation, which travels through space. These radiations allow us to interpret the presence of dark matter.
Dark matter does not emit enough radiation to be seen, but it is there and is analyzed using instruments and statistical analysis, to see how it works. Dark matter is so cold and black that it does not emit anything, therefore it cannot be seen.
Because it cannot be analyzed, it is not known what it is made of. It follows that it can be made up of neutrinos, WIMP particles, non-luminous gas clouds, or even dwarf stars. If you want to know more about the relationship of these concepts with the origin of the universe, you can read about The axion, the particle that could explain the Big Bang or about antimatter and its relationship with the universe. In this context, you may also be interested in what is the universe o what is a galaxy.
How do you know that dark matter is there?
That question is quite interesting, since if it cannot be touched or detected, it is impossible to see. You could say that dark matter is part of our imagination and fantasy, but science is based on evidence.
While it is true that the existence of dark matter is only a hypothesis, that is, it is not yet a proven and proven fact, there is abundant evidence that unequivocally shows that it exists.
It was discovered in 1933, when F. Zwicky proposed its existence in response to an effect that he could not explain: the speed at which galaxies move. It did not agree with what one might expect after the studies and calculations carried out. This had already been detected long before by various researchers.
After some later observations, the existence of a mass that altered space and the gravitational interaction of celestial bodies, but cannot be seen. However, it must be there. To observe the effects of dark matter, one must look at distant celestial bodies, such as other galaxies. A good example of this are the galaxy clusters observed by Hubble and its importance in understanding dark matter. Also, if you are interested in the topic of black holes, are also fundamental in the discussion about dark matter.
What is dark matter for?
If dark matter cannot be seen, touched, or detected in any way, why do we want to know about dark matter? Basically, scientists try to find explanations about the dynamics of the universe. The movement of celestial bodies, inertia, the big bang ... Everything has its explanation if we introduce the presence of dark matter.
Dark matter only really serves to know the universe in a more intimate way. It is a consideration, an entity, that allows us to better understand how the matter we know works, as well as reveal what we do not know. Studying particles whose interaction is so weak allows us to discover aspects of our universe that we would never have imagined. This turns dark matter in a tool, more than a hypothesis, invaluable. And that we can't even see it.
Whatever dark matter is, it is clearly important since most of the universe we know of is made up of it. In addition, it could give us many solutions about the functioning of our universe.