Confusion that AstrophysicistsAstrophysicists And cosmologists have developed only two increasingly distinct and tense measurements of the observable universe’s expansion rate in recent years. via Determination of the famous Hubble-Lemaître constant.
Rigorous and thorough analysis of relevant data Cosmic radiationCosmic radiationAncient the lightthe light in’universeuniverseCollected with Planck satellitePlanck satellite actually gives an estimate of this constant which does not match the one obtained by actually reading it SupernovaeSupernovae SN Iya for a few billion years.
What should be learned from this? Is there an undetected error in the assessment procedures or should it be changed? Standard cosmological modelStandard cosmological model ? But what should change in this model? Our theories aboutDark energyDark energythere Black materialBlack material Or purely theory GravityGravity It uses another theory than thatEinsteinEinstein ? In fact, inventions GalaxiesGalaxies Largest early in history universeuniverse Observable by James-Webb Mond’s theoryMond’s theory Einstein’s theory and dark matter could change the existence of particles.
For 13.8 billion years, the universe has continued to evolve. Contrary to what our eyes tell us when we think of the sky, it is far from static. Physicists have observations of the universe at different ages and run simulations in which they repeat its creation and its 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 fossil radiation map drawn in the Atacama Desert
A new dimension to all these discussions has now been brought in by joint members Atacama Astronomical Telescope (ACT) in a different way than those measured on earth BoardBoard In space, properties of fossil radiation desertdesert From the Atacama to Chile. After 15 years of collection, the ACT is no longer operational from September 2022 PhotonsPhotons of big bangbig bangBut data analysis is still ongoing and several papers have now been published Astrophysical Journal, One of them stands out in particular and may be consulted arXiv.
His summary concludes ” We combine our activities LensLens with the CMB AnisotropiesAnisotropies CMB for stretching constraints of ΛCDMν<0.12 eV (95% cl), for example. Our results show that the universe is spatially flat, conforms to general relativity, and is remarkably well described by the ΛCDM model, while opening a promising avenue for the universe to be spatially flat. BodyBody of NeutrinosNeutrinos with Gravity lensGravity lens From subsequent CMB ground surveys “.
Simons Foundation press release These publications are accompanied by many comments from astrophysicists involved in the ACT adventure, so it has provided some more precise measurements of some elements of modern cosmology than the Planck collaboration. Here is a report by Adrian Duvenvoorten, a researcher in the Cosmic Ray Analysis and Simulation Group at the Simons Foundation: This result is a new victory for the theory GravityGravity Einstein’s. The measured distribution of matter in the later universe is what we expect from our understanding of the early universe. The fact that we can accurately predict how matter moves and evolves over such a long period of time speaks volumes for our understanding of cosmology. »
Matthew Madhavacheril, assistant professor in the Department of Physics and Astronomy at the University of Pennsylvania and senior author of the paper, adds. We have created a new map the massesthe masses Using the distortions of light left by the Big Bang. Notably, the “granularity” of the universe and the rate at which it’s expanding after nearly 14 billion years of evolution provide measurements that show what you’d expect from the Standard Model of Cosmology based on Einstein’s theory. “.
This was confirmed by David Sperkel, president of the Simons Foundation and head of the Fossil Radiation Analysis and Simulation Group, who was previously responsible for the WMap mission before Planck. The new map confirms the current stable picture of dark matter and normal matter, which finds the same large-scale structure “.
Let’s understand what it is all about.
Gravitational lensing to detect diffusion of dark matter
According to the standard cosmological model shown in the CEA video above, from the first seconds of the Big Bang, there were density fluctuations in dark matter intended to rapidly collapse due to gravity and then collapse into normal matter. StarsStarsgalaxies and GalaxiesGalaxies Collects into large fibrous structures over time.
We did some Numerical simulationsNumerical simulations In these processesDeclineDecline Over time, the simulation depends on several parameters, for example the mass of dark matter and neutrinos.
Theory tells us whenproblemproblem Fossil radiation from about 380,000 years after the Big Bang reflects the density of dark matter and baryonic matter due to fluctuations in temperature and the polarization of this light. We can therefore start calculations of numerical simulations using an estimate of these densities.
But over time, forming galaxies and galaxies create gravitational lensing effects by deflecting the light rays that describe the background radiation and have a kind of blurring effect on the primitive image of this radiation. We can reverse the calculations and from measurements of these lensing effects learn the distribution of dark matter masses and how they evolve over time.
With the measurements made possible by ACT, we can not only test the predictions of models based on the presence of dark matter that form large structures, but that gravity forms these structures up to a certain point. and their evolution over time. ACT measurements also make it possible to test cosmological parameters such as the flatness of space in the observable universe.
The new map, and the analysis of measured fluctuations it allows, has come once again to dispel Einstein’s competing theories of gravity and further confirm the existence of dark matter.
