James Webb observed an ancient galaxy that cannot be explained by dark matter

James Webb observed an ancient galaxy that cannot be explained by dark matter

Articles and discoveries are abound about ancient galaxies that can now be well observed by Hubble's successor, James Webb, and that don't really seem to agree with the predictions of the standard cosmological model, although the debate is still far from over. The latest discovery concerns a galaxy four times larger than the Milky Way, just over two billion years after the Big Bang.

We know that the standard cosmological model is based on the existence of never-before-seen particles that should be unable to emit light, or very little, but are able to affect known particles, such as baryons, which are protons and neutrons. By gravitational interaction. Detectors LHCLHC in CERNCERN Try to see it in the products of collisions between proton beams in this large particle accelerator, but particles Substantia nigraSubstantia nigra What is the CosmologyCosmology Perhaps they are so huge that it would be necessary to create them, according to the famous relationshipEinsteinEinstein E = MC2go up to EnergiesEnergies Which would require a collider with a circumference of about 100 kilometers.

Meanwhile, we are still searching for new evidence of the existence and properties of dark matter particles in the universe GalaxiesGalaxies toEdwin HubbleEdwin Hubble. Currently, these particles are still almost the only way the galaxies we observe and the large structures that hold them together originate. Galaxy clusterGalaxy cluster Bundled into threads. We don't really know how to reproduce the properties of fossil radiation from the Big Bang discovered by Penzias and Wilson without these dark matter particles.

But we also know that there is AnomaliesAnomalies Or the properties of galaxies that we understand better if we dispense with dark matter particles and use a modification of the laws of celestial mechanics. NewtonNewton, This theory was actually proposed in the early 1980s by the Israeli physicist Mordechai Milgrom As part of it Modified Newtonian dynamics, known today by the abbreviation Mond. However, it is currently facing difficulty due to observations of the Gaia satellite.

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For 13.8 billion years, the universe continued to evolve. Contrary to what our eyes tell us when we gaze at the sky, what shapes it is far from static. Physicists have observations of different eras of the universe and perform simulations in which they recreate the universe 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 we observe today. © CEA Research

A galaxy four times larger than the Milky Way 11.5 billion years ago

But who really knows what it's all about?

Maybe it is James Webb Space TelescopeJames Webb Space Telescope (JWST) which will help us see things more clearly through study like never before inInfraredInfrared The oldest galaxies that can be observed today, and in this regard, this is the case of the galaxy called JWST-7329. We see it as it was approximately 11.5 billion years ago (which means it is currently at a distance from Earth). milky waymilky way Which can be calculated online thanks to cosmologist New Wright By giving the spectral shift which here is z = 3.2 as AstrophysicistsAstrophysicists In their terminology. Then we find the distance today is about 21 billionLight yearLight year).

JWST-7329 is the subject of an article published in the famous magazine nature Which can be freely referred to arXiv. It showcases the work of an international team led by JWST Carl Glazebrook from Swinburne University of Technology in Melbourne, Australia.

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In the university's press release about JWST-7329, Karl Glazebrook explains: “ We've tracked this galaxy for seven years and spent hours observing it with the two largest telescopes on the planet to determine its age. But it was so red and so faint, we couldn't measure it. In the end, we had to leave Earth and use the James Webb Space Telescope to confirm its nature. This has been very much a team effort, from the infrared sky studies we began in 2010 that led us to identify this galaxy as unusual, to the long hours we spent cakecake And the Very large telescopeVery large telescope We tried to confirm this, but failed, until finally last year when we put in a massive effort to figure out how to process and analyze the JWST data. SpectraSpectra. »

Are galaxies too massive for dark matter cosmology?

The result that came out was that JWST-7329 is actually a galaxy more than 11 billion years older than the Milky Way and contains many more stars.starsstars At that time it was already 1.5 billion years old.

However, it appears that such a galaxy would not have had enough time to form, because the dark matter was not yet sufficiently concentrated CollapsesCollapses The force of gravity collapsed the baryonic matter fast enough to form JWST-7329 at that speed, another example of galaxies that were very advanced and very massive more than 11 billion years ago that was discovered with James Webb.

This explains Claudia Lagos From the International Center for Radio Astronomy Research (Icrr) at the University of Western Australia, which played a critical role in developing… designdesign The theory of the evolution of dark matter concentrations for study.

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The formation of galaxies depends largely on how dark matter is concentrated. The existence of these very massive galaxies occurred very early in the universebeingbeing It poses great challenges before us Standard formStandard form Cosmology. In fact, we don't believe that dark matter structures massive enough to host these galaxies would not have had enough time to form. More observations are needed to understand how common these galaxies are and to help us understand how massive these galaxies really are. »

Karl Glazebrook adds in the same press release that “ The James Webb Space Telescope has discovered increasing evidence of the early formation of massive galaxies. This result sets a new record for this phenomenon. Although it is very striking, it is only one case. But we hope to find more; If we do, it will change our ideas about galaxy formation “.

We know that Mound's theory predicts the early formation of large galaxies.

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