The oldest clusters of dark matter observed in the Universe are not what was expected!

La carte des fluctuations du rayonnement fossile déduite des observations de Planck. © ESA

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[EN VIDÉO] The secrets of the Planck mission The Planck satellite is a formidable time machine, capable of revealing several secrets about the origin, structure and composition of the universe. Cosmologists and astrophysicists have used it to map across the sky, with unparalleled precision, the fluctuations in temperature and polarization of the world’s oldest light, that of fossil radiation. This video produced by the HFI-Planck consortium, the Canopée communication agency and with the help of Jean Mouette of the IAP (Institute of Astrophysics of Paris) explains what this mission consists of. It took about twenty years to prove the existence of neutrinos and about forty that of the Brout-Englert-Higgs boson. How much longer will it take to demonstrate the existence of dark matter particles or, conversely, to demonstrate their non-existence? Remember that the neutrino had been postulated by Wolfgang Pauli to maintain the law of conservation of energy in certain nuclear decays that seemed violate it But to do so one had to admit that the energy that seemed to vanish into thin air was in fact carried away by a particle with no mass, no electric charge, and interacting so little with low-energy matter that could cross 300 Earths without breaking. We now know that there are in fact three types of neutrinos and that they have masses, albeit very low. Dark matter particles are just as ghostly, but paradoxically we need them to explain the existence of galaxies and the structures that bind them together the form of clusters containing roughly a few hundred to a few thousand galaxies. It was under the effect of its gravitational field that ordinary matter collapsed faster than it should have on its own. We know for a number of reasons that these dark matter particles do not resemble those we know on Earth and that they occur mostly in proton collisions at the LHC, although they are precisely tracked there, but still that dark matter is one of the pillars of the Standard Cosmological Model, could not exist and the observations it reports could perhaps also be explained by modifying Newton’s equations of celestial mechanics. We are currently wondering if the first discoveries of galaxies that appear very primitive by the James-Webb telescope, because they were observed as they were more than 13 billion years ago, are not precisely the beginning of a refutation of the dark matter theory and a confirmation. of Mond’s theory. For 13.8 billion years, the Universe has continued to evolve. Contrary to what our eyes tell us when we contemplate the sky, what makes it up is far from static. Physicists make observations at different ages of the Universe and carry out simulations in which they reproduce its formation and evolution. Dark matter appears to have played an important role from the beginning of the Universe to the formation of the large structures observed today. © CEA Research A new surprise in this regard may be emerging in an article published in Physical Review Letters by an international team of researchers led by members of Nagoya University in Japan. Some results obtained with Japan’s Subaru Telescope in Hawaii as part of the Subaru Hyper Suprime-Cam Survey (HSC) research campaign are discussed, in combination with other observations obtained by ESA’s Planck satellite in the form of his famous fossil map. radiation, the oldest light in the observable Universe, emitted around 380,000 after the Big Bang in a few thousand years. A dark matter that distorts the images of galaxies The astrophysicist and cosmologist Laurence Perotto, a member of the col Planck’s collaboration, she had explained to Futura in the archive that she had allowed us to write in which she explained to us the nature of fossil radiation and the analyzes that she and her colleagues had planned to carry out on this radiation in search of fundamental keys to in cosmology and theoretical physics: “The gravitational lens effect allows us to reconstruct the integrated gravitational potential of the last airy surface to date. It is an interesting investigation of the structures of the Universe. Thus, if we achieve this reconstruction, Planck would become an experiment autonomous sensitive to the entire evolution of the Universe, from the primordial universe at the time of the last diffusion to us The surface of the last dispersion is that of a sphere a fiction that surrounds any observer of the observable cosmos and shows him the regions from which the photons of the fossil radiation were emitted when the observable Universe became transparent because its density is so weak that the photons of that time could, from then on, travel without colliding with charged particles that would spread them over great distances.gravitational, is an effect of deflection of light rays by a gravitational field that leads to the deformation of the initial 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 the effects of gravitational lensing allows us to probe mass distributions in the observable cosmos, including masses of dark matter that itself does not radiate. straight line But in a space deformed by a massive celestial body, such as a galaxy, this trajectory deviates! Thus, a light source located behind a galaxy has an apparent position different from its actual position: this is the phenomenon of the gravitational mirage. This video comes from the web documentary “L’Odyssée de la Lumière” (…) and has been integrated into the web documentary “Embarquez avec la Matière Noire” ( ) . © CEA-AnimeaOn used this effect to estimate the presence and changes in the distribution of dark matter up to about 8 to 10 billion years ago, going back in time. As Laurence Perotto had also explained to us, the effects of weak gravitational lensing produced by galaxy clusters and foreground galaxies in the last scattering surface contaminate the study of fossil radiation and we must somehow subtract from signal this noise to return to it. the primitive state of fossil radiation. This makes it possible, in particular, to track the mythical primitive B modes of polarization of fossil radiation. The highlighting of these modes would convincingly demonstrate the existence of a vertiginous inflationary phase of the expansion of space during the Big Bang. The cosmologist had mentioned in the extract from her data sheet that we have given, the measurement of the weak effect of gravitational lensing could in The theory informs us about the presence and variable characteristics in time and space of dark matter from the appearance of the first galaxies to the present day through use of fossil radiation galaxies detected with the HSC in the Planck measurements of fossil radiation. We hadn’t gone further before because the galaxies, whose images were distorted by gravity, were too faint to make valid measurements. But now, researchers can go back about 12 billion years into the past of the observable cosmos. Remarkably, although still to be confirmed, the size characteristics of the dark matter concentrations between 8 and 12 billion years ago do not appear to follow the predictions of the Standard Cosmological Model, the fluctuations of the dark matter density during this period appear to be lower than Yuichi Harikane, one of the authors of the discovery and a professor at the Cosmic Ray Research Institute of the University of Tokyo, does not hesitate to explain: “Our conclusion is still uncertain. But if it is true, this would suggest that the entire model is flawed as it goes back in time. This is exciting because if the result holds after reducing the uncertainties, it could suggest an improvement in the model that could provide the nature of dark matter itself. With this goal, cosmologists still need to increase the volume and precision of available data, which they will soon be able to do with the commissioning of the Vera C. Rubin Observatory, aba ns called LSST. 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