Dark matter, one of the greatest mysteries of our universe
The galaxies that fill our universe rotate at very high speeds that can reach 80 km/sec for elliptical galaxies and up to 500 km/sec for other, more massive galaxies. At such speeds, it must completely disintegrate, since the gravitational force generated by the matter of which galaxies are composed is completely insufficient. However, they have been held together since the beginning of the universe.
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Scientists are convinced that an invisible element is stepping in to hold it together and provide this extra oomph. They called this mysterious element dark matter. Dark matter behaves differently from visible matter. It is impervious to electromagnetic force, which makes it unable to emit or reflect light and is therefore easily detectable.
So researchers around the world have not been able to see this dark matter, which nonetheless represents six times the mass of visible matter and makes up up to 27% of the universe. Scientists were only able to infer its existence from the gravitational effect it produces on visible matter in the universe.
What challenges the scientific community the most is to know the components of this dark matter!
Enormous gravitons, virtual particles?
One advanced theory posits that dark matter contains particles known as supersymmetric particles, that is, particles associated with particles known from the Standard Model. Several candidates have also been put forward as being able to enter the formation of this dark matter. of between it , AxionsNeutrinos and massive particles are weakly interacting. Recently, researchers, including researchers from Lyon University and Korea University, wondered if a hypothetical particle, the massive graviton, could be a valid candidate!
Massive gravitons are particles that were produced in collisions between ordinary particles immediately after the Big Bang in the dense and bubble environment of the early universe. According to astronomers and physicists, the formation of these predicted particles only lasted for a very small moment less than a second.
For massive gravitons to be good candidates to participate in the formation of dark matter, they must have been produced in sufficient quantities during this very short moment. Since the process that led to their formation appears to be extremely rare, the researchers attempted to calculate their production rate and found that after picoseconds after the Big Bang, enough particles had been produced to allow for sufficient collisions and thus the formation of an equally sufficient amount of massive gravitons.
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Dark matter is produced after the picosecond after the Big Bang
According to their findings, scientists from the Universities of Leon and Korea believe that dark matter was produced 1 picosecond after the Big Bang at a time corresponding to the presence of the so-called “classical” particles that were also newly formed. Existing physics theories describe these particles well.
Therefore, scientists conclude that massive gravitons were caused by collisions between particles such as electrons, quarks and Higgs bosons immediately after the Big Bang.
The results collected by the researchers should inspire new studies about the massive gravitons that should “bathe” the entire universe. Meanwhile, the scientists behind this study continue their work on dark matter. They plan to use the graphiton model they just produced, but are continuing their research to evaluate other candidates likely to enter into the composition of this very strange dark matter.
They are also interested in the role played by a standard particle called radiation. They also hope to be able to conduct experiments on this particle inside particle colliders such as Large Hadron Collider from Geneva. Are massive gravitons an integral part of dark matter? The results obtained go in this direction, even if it is always difficult to confirm it with accuracy.
To be sure, the existence of this dark matter that explains the existence of the cosmic web and the flaws detected in the Big Bang’s residual glow still retain part of its mystery.
>> Read also: Towards a complete overhaul of the cosmological model?
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