A new theory that dark matter appeared before the big-bang trainer of the universe is advanced by American astrophysicists, who also think they have found a way to detect it.
Dark matter, which makes up about a quarter of the universe, is certainly one of the most elusive mysteries of physics.
The universe decomposed
To date, humanity has observed only a tiny part of the Universe: visible (or ordinary) matter. This includes gases and heavier elements, such as iron, which constitute celestial objects such as stars and planets. However, it represents only 5% of the composition of the Universe.
There is another form of matter, according to the vast majority of astrophysicists, that would form a cosmic web between celestial objects, large and small.
If several observational clues tend today to reinforce its existence, this dark matter, whose gravitational influence would also lead to the formation of the great structures of the Universe, remains to be observed. It would make up 27% of the Universe.
Since none of the properties predicted in the models have yet been measured, some scientists prefer to describe it as a missing mass whose abundance and distribution remain to be determined.
Did you know?
There would also be dark energy in the Universe. Again, this is a theory since it has not been observed yet. It would be a little less than 70% of the universe, and it would explain various astrophysical observations, including the acceleration of the expansion of the universe.
Rethink the big bang
Astrophysicist Tommi Tenkanen and his colleagues at Johns Hopkins University have created a new mathematical model that suggests that dark matter would have appeared in fractions of a second, just before the big bang, at the time of cosmic inflation during which space began its rapid expansion.
This theory runs counter to the generally accepted theory that this inflation occurred a few seconds after the big bang.
Our work reveals a new link between particle physics and astronomy.
If dark matter is composed of unknown particles born before the big bang, these certainly influence how galaxies are spatially distributed in a unique way. This link can be used to reveal their identity and draw conclusions about the time that preceded the big bang , says the scientist.
Currently, astronomers believe that the gravitational effects of dark matter shape the movement and distribution of visible matter in space.
For many years, therefore, astrophysicists thought that dark matter was a residual substance of the big bang, despite the fact that all experimental research to show it had failed.
If the dark matter was really a relic of the big bang, the researchers should have detected some direct signals in different particle physics experiments.
Dark matter would have been present before the rest of the matter contained in the nascent Universe.
Cosmic inflation would have led to the abundant production of a new type of particle called scalars. So far only one particle of this type has been discovered, the Higgs boson. These particles have a zero spin. In quantum physics, spin is one of the properties of particles, such as mass and electric charge.
We do not know what dark matter is, but if it has something to do with scalar particles, it could be older than the big bang.
With our mathematical scenario, we do not have to assume new types of interactions between visible matter and dark matter beyond gravity, of which we already know the existence , explains Tommi Tenkanen.
A concept already known
If the idea that dark matter existed before the big bang is not new, no one had been able to make calculations that support this idea.
Researchers have always neglected the simplest possible mathematical scenario for the origins of dark matter.
These works also suggest a way to discover the origin of dark matter by observing the signatures of the presence of dark matter in the distribution of matter of the Universe.
answers coming soon?
All these questions could be answered by 2022 with the launch of the Euclid Space Telescope by the European Space Agency.
This mission of at least 7 years aims to study the universe with extreme precision by mapping the distribution and evolution of dark matter and dark energy.
The detail of the present work is published in Physical Review Letters.