The 13 galaxies taken by the James Webb telescope and the things we can’t explain

The 13 galaxies taken by the James Webb telescope and the things we can’t explain

“They are too stupidly bright to be noticed!” This is the comment of an expert in the sector, Rohan Niduan astronomer at the Massachusetts Institute of Technology, began looking at the images I took James Webb Space Telescope (JWST) Since July last year. The JWST space voyeur, chartered by the US, Canadian and European space agencies, does just that. good job In resuming the history of our universe.

of his most recent work, posted by natures February 22ndtakes us almost back in time 13 billion years, approximately 300 to 700 million years after the Big Bang. Photo display Thirteen galaxies, six of which are particularly huge. or a large block. To tell the truth, the pictures don’t make a great impression. Small red blurry dots on a black background. It is impossible to discern the stars within it, or even its spiral or elliptical shape. Very far, but the intensity of the points and their colors allow you to determine the distance and mass of these objects.

Brief explanation. Since the universe is not static, these galaxies are moving away from us and their light changes color, like the sound of a train whistle, which we hear more seriously when it is moving away, after it has passed. Then the astronomers calculate the differences between the theoretical spectrum and the receiving spectrum to infer the distance. More precisely, they are based on two specific color signatures, one relating to young stars, the other to older stars. The received light intensity of the mass, associated with the models that connect the mass and the luminosity, is used. If there is a “red” figure, we are dealing with large galaxies.

Let’s go back to the images from the Webb telescope. The most noteworthy event is not the distance of the above-mentioned thirteen galaxies Webb “sees” further, however their mass. Six of the thirteen discovered galaxies exceed a mass 10 billion suns One exceeds 100 billion, which puts it closer to our Milky Way. In theory it should not exist. Early in the history of the universe, there wasn’t enough matter to form and ignite Lots of stars. The Milky Way, for example, is thirty times more compact and is, by comparison, very small: It has existed for about ten billion years. Until now, objects of this magnitude were not seen until the first billion years after the Big Bang. It is true that the method for estimating the mass and distance of these galaxies introduces a great deal of uncertainty, however Nothing does add. However, the same team to caution. Talk about galaxies “candidates” not galaxies “discoverer”.

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As evidence of these difficulties, between July and December 2023 pre-publication, it was submitted to naturesThings have changed. the July 22ndThe age range of the galaxies was between 400 and 700 million years, and two of them had masses greater than 100 billion suns. Five months later, he was the “youngest” I got old One hundred million years old and one ten times thinner. Very effective diet thanks to the refinement of the results, but something does not add up.

Possible hypotheses:We may also think that models about mass and luminosity are incorrect. Very large and very bright stars can form in such galaxiesAnd But with less mass, which could change the way we estimate total mass“, Suggest Françoise Combes, Lecturer at the College de France.

Another hypothesis: The strong luminosity could be linked to the presence, in the center of these galaxies, of a supermassive black hole, which would radiate with the force of the gases falling on it, evoking a signature similar to that of stars. These imitators are already known things, called Quasars. “The evidence shows that at least one of our 13 candidates could be a quasar. watching Evo Labof Swinburne University of Technology in Melbourne, Australia, is among the authors of the paper he published naturesMQuasars are rare, so it is unlikely that all of our galaxies are quasars. If it is confirmed also Only one would actually be a discovery, because theory predicts that there shouldn’t be any“.

The last possibility, suggested by Ivo Lappi: “If only one of these candidates is confirmed, the way we think about galaxy formation will need to be revised. That means there is a short cut to making these monsters very quickly and efficiently.”. Which means revising the Standard Model that describes the entire universe, from the great explosion And to this day. According to the model, large galaxies are born from smaller galaxies, which takes time. Monsters are revealed in great numbers, can not exist. Note that the Standard Model is questioned periodically, simply because it doesn’t explain everything. The main problem is that the model provides for the so-called ambiguity dark matter. We don’t know what it is, or what it’s made of, but it appears to be essential to the stability of the universe.

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A brief summary of what cosmologists know or think they know about the universe. After the Big Bang, the newborn universe begins to cool. In a few million years, the turbulent plasma gas that fills space will subside. Electrons, protons, and neutrons combine to form atoms, most of which are hydrogen. Things are silent in complete darkness for an unknown period of time: Age of the dark universe. Then something happens.

Most of the material left over from the Big Bang is something we don’t know what it is and can’t see it. Baptized dark matter, to be precise, has a very important influence on the universe, especially in its infancy. According to the Standard Model, cold dark matter (slow-moving invisible particles) exists in the universe, so chaotic. In certain areas, where its density is higher, it begins to collapse and form deities “blocks”. Visible matter, i.e. atoms, cluster around these clumps. Even when the atoms cool enough, they condense more and more compactly, until the process of nuclear fusion is triggered. The first stars literally see the light. was light.

These new sources of radiation, for energy, “recharge” the hydrogen atoms, ionizing them from the neutral elements they are. After that, the omnipresent gravitational force begins and maintains the process of growth of more complex structures, the real architect of the cosmic web of galaxies that we observe today.

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in the meantimeThe universe continues to expand, as noted by Edwin Hubble, an American astronomer, in the 1920s. At the end of the 1990s, the telescope that gave it its name, the Hubble Space Telescope, gathered evidence that the expansion It’s accelerating In a gravity-defying way. This acceleration appears to be fueled by the repulsive energy of space itself. She was called dark energy, It is represented by Λ, the Greek letter lambda.

If one inserts the values ​​for dark matter, visible matter, and radioactive matter into Einstein’s equations of general relativity, one gets a form How does the universe evolve?. It is called the ΛCDM (cold lambda dark matter) model and is able to explain all cosmological observations. Not bad for the model. be careful with that, It’s just a model. Right until proven wrong.

[Foto in evidenza, credits: NASA, ESA, CSA, STScI]

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