Dark matter will not behave as expected 8 billion years ago

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[EN VIDÉO] Secrets of the Planck Mission
The Planck satellite is a powerful time machine, capable of revealing to us various secrets about the origin, structure and composition of the universe. Cosmologists and astrophysicists have used it to map in the celestial vault, with unequaled precision, temperature and polarization fluctuations of Earth’s oldest light, fossil radiation. This video, produced with the help of the HFI-Planck Consortium, communications agency Canopy, and Jean Muet of the IAP (Institute of Astrophysics in Paris), explains what the mission consists of.

It took twenty years to prove its existence the neutrino And about forty for that Braut-Englert-Higgs boson. How long will it take to demonstrate the existence of its particles? black matter Or on the contrary to demonstrate their non-existence?

Note that neutrinos were predicted by Wolfgang Pauli Maintaining the law of conservation of energy in certain nuclear decays that it appears to violate. But for him it must be recognized that the energy that is disappearing into the vacuum is actually carried by a particle mass, with no electrical charge and interacting so little with low-energy matter that it can travel 300 Earths without stopping. We now know that there are actually three types of neutrinos and that they have masses, albeit very small.

Dark matter particles are just as physical, but conversely we have to account for their existence galaxy and structures that group them together to form clusters containing hundreds to thousands of galaxies. It is under the influence of their field gravity That ordinary matter breaks down faster than itself. We know for several reasons that these particles of dark matter do not resemble what we know on Earth and are produced specifically in collisions. Proton per LHCAlthough they are precisely tracked there.

However, although dark matter is one of the pillars Standard Cosmological ModelIt cannot exist and the observations it reports can also possibly be explained by change equation celestial mechanics Newton. One wonders if the first discovery of a galaxy that seems so primitive telescope James-Webb, because they observed more than 13 billion years ago, not precisely The beginning of a refutation of the dark matter theory and a confirmation of the monad theory.

Over 13.8 billion years, the universe continued to evolve. Contrary to what our eyes tell us when we think of the sky, it is far from static. Physicists have observed the universe at different ages and run simulations to re-enact its formation and evolution. Dark matter appears to have played a major 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 at the end the nose In a published article Physical review letter by an international team of researchers led by members of Nagoya University, Japan. It deals with some of the results obtained with the Japanese Subaru Telescope, within the framework of the research campaign in Hawaii. Subaru Hyper Supreme – Cam Survey (HSC), combined with other observations obtained by Planck satellite of’ESA In the form of his famous map Cosmic radiationthe oldest the light of’the world Observable, emitted after about 380,000 the big bang In a few thousand years.

Dark matter is what distorts the picture of galaxies

Let us also remember Astrophysicist and cosmologist Lawrence Perrotto, a member of the Planck collaboration, explained to Futura in the file he let us write in which he explained the nature of fossil radiation. And the analyzes that he and his colleagues planned to produce in search of the fundamental keys to this radiation cosmology And the physical Theoretician: ” in effect Gravitational lens The integrated gravitational potential of the end surface makes it possible to reconstruct expansion Until today. It is a fascinating exploration of the structure of the universe. Thus, if we succeed in this reconstruction, the Planck will become an autonomous experiment sensitive to the entire evolution of the universe, from the primordial universe at the time of the last dispersion to ours.

The final scattering surface is an imaginary sphere surrounding any observer the cosmos Observable and shows him that from the regions Photon Fossil radiation is when the observable universe becomes transparent Because its density had become so low that from then on photons could travel without colliding with charged particles that would scatter them over great distances.

The resulting gravitational lensing effect, in this case the so-called weak one or even the gravitational shear, is an effect of the deflection of light rays by a gravitational field that distorts the initial image of a galaxy by a large intergalactic mass. and an observer. We can infer from the distortion the mass of the body it produces, so that measuring the gravitational lensing effect makes it possible to probe the mass distribution in the observable universe, including the mass of dark matter that itself does not radiate.

In a vacuum, light usually travels in straight lines. But this trajectory deviates in space distorted by massive celestial bodies like galaxies! Thus, a light source located behind a galaxy has an apparent position that differs from its actual position: this is the case of gravitational mirages. This video is derived from the web documentary “ Odyssey of light (http://www.odysseedelalumiere.fr/comp…) and integrated into the web documentary ” Journey with Dark Matter (lamatierenoire.fr). © CEA-Animea

This effect has been used to infer the presence and distributional changes of dark matter from about 8 to 10 billion years ago. As Lawrence Perrotto explained to us, the weak is produced by the gravitational lensing effect Cluster of galaxies And last scattered surface foreground galaxies contaminate the fossil radiation study, and this noise needs to be somehow subtracted from the signal to return to the primordial state of the fossil radiation. This makes it possible to track myths in particular B-mode Primitives of polarization of fossil radiation. Highlighting these modes would convincingly demonstrate the existence of a vertiginous inflationary phase of the expansion of space during the Big Bang.

Clusters of dark matter that formed from the Big Bang

But, as the cosmologist pointed out in his file citation that we provided, measurements of the weak gravitational lensing effect could theoretically inform us about the presence and changing properties of dark matter in time and space. The first galaxies to date using fossil radiation.

The Japan-led team was able to precisely make such observations by measuring the effect of galaxies detected with the HSC on measurements of Planck’s background radiation over 8 billion years. We didn’t go any further earlier because the galaxies, whose images were distorted by gravity, were too faint to make valid measurements.

But now researchers can go back almost 12 billion years in the observable universe.

Interestingly, although not yet confirmed, the size characteristics of the dark matter density 8 to 12 billion years ago do not seem to follow predictions. Standard Cosmological ModelFluctuations in dark matter density during this period appear weaker than expected.

Yuchi HurricaneOne of the authors of the discovery and Professor DrInstitute for Cosmic Ray Research from the University of Tokyo, does not hesitate to explain: ” Our conclusions are still uncertain. But if true, it would suggest that the whole model is flawed as you go further back in time This is exciting because if the result holds after reducing the uncertainty, it could suggest an improvement in the model that could provide the nature of dark matter itself. »

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

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