Dark matter is one of the great enigmas of Physics and there is no shortage of scientists frying their brains in an attempt to discover its origin and what, after all, it is. Just to refresh your memory, it is "something" that does not emit, absorb or reflect any radiation, but that physicists know that exists because of the way "it" interacts with conventional matter in the Universe.
In fact, the interaction is intense! So much so that, according to scientists, it is dark matter that keeps galaxies cohesive, preventing them from dispersing through the cosmos, and close to 85% of the universe's mass would be composed of it. Therefore, it is possible to understand the reason why physicists want so much to discover what has such an influence over the space and dedicate themselves to testing theory after theory in search of answers. For yet another one was put to the test recently and, for the moment, dark matter continues to prevail in the item “undecipherable cosmic mystery”.
It was bad
The theory tested this time was that of "sterile neutrinos" or "inert neutrinos", hypothetical particles that would interact only through gravity – which would fit with the interaction of dark matter – and from which evidence would have been detected about 6 years ago, but whose existence has not been proven due to the lack of further observations.
It hasn't been this time yet … Source: Medium / Reproduction
In fact, it is not the first time that scientists have associated neutrinos – which have a neutral charge and very little mass – to dark matter. The problem is that the fact that these particles have a small mass creates conflict with what is established by the Standard Model of Particle Physics. That is why the existence of such inert neutrinos was proposed and, in 2014, a team identified signals coming from galaxies neighboring ours in the order of 3.5 keV (acronym for kilo electron volt) that were associated with the particles.
At the time, scientists suggested that this energetic signal could be generated by the disintegration of such sterile neutrinos. So, during the tests done now, physicists analyzed no less than 20 years of observations made by the X-ray Multi-Mirror Newton, the largest space telescope of the European Space Agency in operation, and the expectation was to find these same signals at the limits of the Milky Way, since, according to observations, dark matter appears to accumulate around galaxies.
But, unfortunately, physicists were unable to find any trace of the inert neutrinos, which threw another attempt to detect dark matter to the ground. It is important to note that the fact that scientists have not identified sterile neutrinos does not completely rule out the possibility that they actually exist or are related to the origin of dark matter. However, researchers will have to think of other methods and theories to test to try to unravel this stubborn puzzle.