The oldest clusters of dark matter observed in the universe are not as expected!

You will also be interested


[EN VIDÉO] Secrets of the Planck Mission
The Planck satellite is a formidable time machine capable of revealing to us numerous secrets about the origin, structure and composition of the universe. Cosmologists and astrophysicists have used it to map across the firmament, with unparalleled precision, the temperature and polarization fluctuations of the oldest light in the world, fossil radiation. This video produced by the HFI-Planck consortium, the Canopée communication agency and with the help of Jean Mouette, from the IAP (Institute of Astrophysics of Paris), explains what this mission consists of.

It took twenty years to demonstrate the existence of neutrinos and about forty for that of Brout-Englert-Higgs boson. How much longer will it take to demonstrate the existence of particles of black fabric or, on the contrary, to demonstrate their non-existence?

Remember that the neutrino had been postulated by Wolfgang Pauli to uphold the law of conservation of energy in certain nuclear decays which appeared to violate it. But to do so one had to admit that the energy that seemed to disappear into nothingness was actually carried away by a massless particle, with no electrical charge and interacting so little with low-energy matter that it could cross 300 Earths without going break. We now know that there are actually three types of neutrinos and that they have masses even though they are very small.

Dark matter particles are just as ghostly, but paradoxically we need them to account for the existence of galaxies and structures that bring them together in the form of clusters containing from a few hundred to a few thousand galaxies very roughly. It is under the influence of their field of gravity that ordinary matter collapsed faster than it should have done on its own. We know, for various reasons, that these particles of dark matter do not resemble those we know on Earth, and which are mainly produced by collisions between protons at the LHC, although they are tracked there.

However, although dark matter is one of the pillars of Standard Cosmological Modelit could not exist, and the observations it reports might also be explained by modification equations celestial mechanics Newton. One is currently wondering about the first discoveries of galaxies, which seem very primitive telescope James-Webb, because they were observed as they were more than 13 billion years ago, it is not accurate a beginning of a refutation of the theory of dark matter and a confirmation of the Mond theory.

For 13.8 billion years, the universe has continued to evolve. Contrary to what our eyes tell us when we look at the sky, what is made up of the sky is far from static. Physicists have observations at different ages of the universe and perform simulations in which they play out its formation and its evolution. It appears that dark matter has played a major role since the beginning of the universe until the formation of the large structures observed today. © CEA Research

A new surprise in this regard may be about to end nose in an article published in Physical review letters by an international team of researchers led by members of Nagoya University in Japan. It deals with certain results obtained with the Japanese Subaru telescope in Hawaii as part of the research campaign from Subaru Hyper Suprime – Cam Survey (HSC), in combination with other observations obtained by Planck satellite of’ESA in the form of his famous map of cosmic radiationthe oldest light ofUniverse observables, emitted about 380,000 after big bang in a few thousand years.

Dark matter that distorts images of galaxies

Let’s also remember what the astrophysicist and cosmologist Laurence Perotto, member of the Planck collaboration, had explained to Futura in the file that she had allowed us to write in which she explained to us the nature of the fossil radiation and the analyzes that she and her colleagues had planned to make of this radiation in search of fundamental keys to it cosmology and theoretical physics: The effect of gravitational lens makes it possible to reconstruct the integrated gravitational potential of the surface of the latter diffusion until today. It is an interesting study of the structures of the universe. Thus, if we succeed in this reconstruction, Planck would become an autonomous experiment sensitive to the evolution of the entire universe, from the primordial universe at the time of the last diffusion to us. “.

The surface of final scattering is the surface of a fictitious sphere that surrounds any observer in cosmos observable and shows him the regions from which it photons fossil radiation, when the observable universe became transparent because its density became so low that the photons of the time could travel without colliding with charged particles, which would scatter them over great distances.

The induced gravitational lensing effect, in this case the so-called weak one or even gravitational shift, is an effect of deflection of light rays from a gravitational field that leads to deformation of the original image of a galaxy by a large mass interposed between this galaxy and an observer. From the deformation, we can deduce the mass of the body that produces it, so measuring gravitational lensing effects makes it possible to probe mass distributions in the observable cosmos, including masses of dark matter that do not themselves radiate.

In a vacuum, light normally travels in a straight line. But in a space deformed by a massive celestial body, like a galaxy, this trajectory deviates! Thus, a light source located behind a galaxy has an apparent position different from its real position: this is the phenomenon of gravitational mirage. This video originates from the web documentary ” The Odyssey of Light (http://www.odysseedelalumiere.fr/comp…) and has been integrated into the web documentary ” Get on board with dark matter (lamatierenoire.fr). © CEA-Animea

This effect has been used to estimate the presence and distributional changes of dark matter up to about 8 to 10 billion years ago. As Laurence Perotto also explained to us, the weak gravitational lensing effects were produced by a cluster of galaxies and the galaxies in the foreground of the last scattering surface contaminate the study of the fossil radiation, and it is necessary to somehow subtract this noise from the signal to go back to the primitive state of the fossil radiation. This makes it especially possible to track down the mythical B mode primitives of the polarization of the fossil radiation. Highlighting these modes would convincingly demonstrate the existence of a staggering inflationary phase of the expansion of space during the Big Bang.

Clusters of dark matter that have been structured since the Big Bang

However, as the cosmologist had mentioned in the excerpt of her file that we have provided, the measurement of the weak gravitational lensing effect could in theory inform us about the presence and the variable characteristics over time and space of dark matter from the appearance of the first galaxies until in day using fossil radiation.

The Japanese-led team managed to make just such observations over 8 billion years by measuring the effects of galaxies detected with the HSC on Planck’s measurements of the background radiation. We hadn’t gotten further before because the galaxies, whose images were distorted by gravity, were too faint to make valid measurements.

But now scientists can go back about 12 billion years in the observable cosmos.

Remarkably, although still to be confirmed, the magnitude characteristics of dark matter concentrations between 8 and 12 billion years ago do not seem to follow the predictions of Standard Cosmological Modelthe fluctuations in the density of dark matter during this period look weaker than expected.

Yuichi Harikaneone of the authors of the discovery and professor atInstitute for Cosmic Ray Research from the University of Tokyo, does not hesitate to explain: ” Our conclusion is still uncertain. But if true, it suggests that the whole model is flawed when you go further back in time. This is exciting, because if the result holds after reducing the uncertainty, it could indicate an improvement in the model that could provide the nature of dark matter itself. »

With this goal in mind, cosmologists must still increase volume and the accuracy of available data, as they will soon be able to do with the commissioning of the Vera C. Rubin Observatory, formerly known as OHSA.

Interested in what you just read?

Leave a Comment