The universe is strange. It is very, very difficult to understand what is happening in it, but scientists do not give up trying. One of two ways to find out what lies beyond the Earth is by looking at the light emitted and absorbed by matter in the universe: through direct astronomical observation. The second way is to use the laws of gravity and the effects of matter and energy on the curvature of space to try to establish how much mass should be present in a particular physical system through mathematical calculations. One of the biggest mysteries of modern astrophysics is that the results of these two independent methods, which measure the same universe, do not match. For some reason, anything that emits or absorbs light - from stars to black holes, planets, gas, dust, plasma, and so on - is only about 15% of the total amount of matter that should be there. But how is this possible?
Dark matter - a hypothetically existing form of matter,which does not participate in electromagnetic interaction, and therefore is inaccessible to direct observation. Scientists believe that dark matter is about a quarter of the mass - the energy of the universe and manifests itself only in gravitational interaction.
Does dark matter exist?
Despite the fact that direct evidence of the existence of mysterious dark matter has not yet been found, from an astrophysical point of view there is a huge amount of circumstantial evidence confirming the existence of this mysterious substance. First, dark matter behaves as ifit has mass, but it does not emit or absorb light. Instead, it bends light by gravitationally acting on spacetime. Secondly, the huge set of available data indicates that either there is something in space that does not correspond at all to our understanding of the Universe, or the dominant form of matter in the Universe has not yet been discovered.
Although the first observations suggestingthe existence of dark matter appeared in 1933, convincing data were obtained only by the 1970s. It was then that astronomer Vera Rubin first discovered the discrepancy between the mass of all visible objects in the galaxy with the mass of the galaxy itself. The astronomer determined that this invisible substance is extremely common and that most of the universe consists of it.
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Today the world knows this substance as dark matter, which does not reflect, scatter, emit, refract or absorb light. Nevertheless, researchers today believe that about 85% of all matter in the universe is dark matter. And yet, to date, there is no conclusive evidence for the existence of dark matter.
Mysteries of the Universe
So, if dark matter exists, let me remind youthat earlier black holes and gravitational waves were also considered hypothetically existing objects - then all its interactions with the environment occur with the help of gravity. This means that the mysterious substance must have moved very slowly compared to the speed of light even shortly after the Big Bang.
Thus, the very nature of what is behind “dark matter” is still completely incomprehensible to scientists.
Moreover, researchers do not understand what exactlyshould (and should not) do dark matter in the universe. The sheer number of unknown properties that this substance possesses raises even more questions. For example, what is the mass or density of dark matter particles in the universe? Is dark matter light, and if so, how many dark matter particles are there? According to Forbes, scientists have no idea how many dark matter particles exist and what their mass is. Some researchers do not even exclude that dark matter may even be a liquid, and not particles, as we assume. We do not know if dark matter is composed of the same "matter" or if there are many varieties of it.
See also: Could dark matter be older than the Big Bang?
Here's the simplest guess: there is only one new component of matter, and that is what we are missing. But there are many unknowns in space, and therefore there are many different methods that can be used to solve the riddle of dark matter. It is also necessary to take into account the fact that scientists do not know what type of particles the particles of dark matter belong to (if we proceed from the assumption that dark matter really consists of particles), as well as whether antimatter exists.
All particles known today are of two types: fermions (like electrons or neutrinos) and bosons. If dark matter is composed of bosons, then these particles behave like their own antiparticles. But if it consists of fermions, then this substance has antiparticle analogues. In this case, the existence of "dark antimatter" will be a reality. In the meantime, both us and scientists can only guess what dark matter is and whether it exists. What do you think about this? We will wait for the answer here.