Three galactic “red monsters” unearthed within the younger Universe defy theories | EUROtoday
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Dn the depths of the younger Universe, explored with unprecedented precision by the James-Webb telescope, monstrous galaxies are revealed, defying our present data. How was the Universe capable of create galaxies extra huge than the Milky Way in only a billion years? This query is on the coronary heart of an necessary discovery printed this Wednesday in Nature. An worldwide crew, led by the University of Geneva (Unige) with a big contribution from CEA Paris-Saclay, has recognized, practically 13 billion gentle years away, three distinctive galaxies that problem our understanding of the primitive universe.
“It’s like looking at thirty-six babies who have just been born [car 36 galaxies au total ont été étudiées précisément ici, NDLR]and that out of the thirty-six babies, there are three who are 1.50 m tall or who weigh 60 kilos. We would say to ourselves: this is not possible, a mother cannot give birth to such a child,” illustrates David Elbaz, scientific director of the astrophysics division at CEA Paris-Saclay and co-author of the examine, interviewed by The Point. These three “red monsters”, as researchers have nicknamed them due to their attribute colour as a consequence of their excessive mud content material, are in actual fact two to 4 occasions extra huge than our present galaxy!
Such a discovery wouldn’t have been attainable with out the James-Webb house telescope, whose means to watch within the infrared permits us to see via the clouds of mud and thus to unravel a bit of extra the mysteries of the Young universe. “Before, with the Hubble telescope, when we looked at these galaxies, it was as if we knew there was an animal but we couldn’t tell if it was a squirrel or an elephant. With James-Webb, we know and can determine how many squirrels I have, how many elephants I have and whether they are big or not,” explains the researcher. Well, these are three “mammoths” that the crew found.
Calculate the mass of galaxies
But how can we “weigh” a galaxy? The gentle we obtain from a galaxy comes from all its stars, however you need to know {that a} huge star emits proportionally rather more gentle than a small one. “A star ten times more massive than our sun shines like 4,000 suns. So, when I receive the equivalent of 4,000 times the sunlight, it can either come from 4,000 stars of the mass of the sun, or from a star of ten times the mass of the sun,” David Elbaz explains to us. Now, as you’ve understood, even when they emit an identical quantity of sunshine, the sum of the mass of those 4,000 small stars is way larger than that of a single huge star.
“Fortunately, large stars shine in the ultraviolet while small stars shine in the visible or near infrared. By decoding this language of light, we can therefore know how many small and large stars there are. » In other words, to calculate the mass of galaxies, researchers must analyze the colors of light. Therefore, to go back to the star composition of a galaxy and deduce its mass, scientists rely on computer simulations. “We create millions of virtual galaxies with different combinations of stars and, by comparing them to our observations, we find those that most resemble real galaxies, which allows us to estimate their mass. »
This new work is part of a particular context. Indeed, the first James-Webb observations had created a stir, with studies suggesting the existence of “impossible galaxies”, so huge that they’d have required extra atoms than the Universe contained in these areas. . Which, in accordance with some, required questioning the age of the Universe, and even the Big Bang itself. This new examine, extra exact and rigorous because of an actual measurement of distances and much, restores calm: the overwhelming majority of the 36 galaxies noticed are utterly regular. Only these three “red monsters” nonetheless elevate questions.
Cosmic manna, filaments and oases
Because these galaxies type stars at a breakneck tempo – round 1,000 suns per yr, when our galaxy solely creates three to 5. Such speedy progress forces astrophysicists to assessment their fashions. “It is not as fundamental as questioning the Big Bang or the age of the Universe but it is still, for astrophysicists, something quite major because it allows us to know if we know how to explain how stars are born and how galaxies evolve,” underlines the researcher. For David Elbaz, it is as if we have been strolling within the desert and discovering an oasis: “These galaxies must be nourished by cosmic manna, because we cannot form 1,000 times the mass of the sun every year without having enormous reservoirs of material available. »
To Discover
Kangaroo of the day
Answer
To unravel this thriller, David Elbaz is presently persevering with his analysis alongside Mengyuan Xiao, his former doctoral pupil and first creator of the examine. Their instinct? These monstrous galaxies may have grown sooner than others because of their setting. “For at least two of them, we noticed that there were more galaxies around, which suggests that they are in particularly dense regions of the universe,” explains the researcher. But the crew stays cautious: “For now, with such a small sample, it could still just be a coincidence. »
ALSO READ The Euclid telescope delivers the first piece of its cosmic puzzleTo find out, scientists are now working to calculate the precise distance and mass of a larger sample of galaxies. Because these “red monsters” may very well be witnesses to a hitherto underestimated cosmic actuality: that of interconnected filaments with, in locations, like highways of matter which nourish sure areas of the Universe at an exceptionally excessive price. This speculation couldn’t solely clarify the speedy progress of those galaxies, but additionally make clear our imaginative and prescient of the position of this sort of cosmic framework which has formed the Universe. A situation all of the extra credible since, even in our neighborhood, we observe remarkably huge galaxies on the coronary heart of enormous galactic clusters. Could these monsters from the younger universe be the ancestors of those giants nearer to us?
https://www.lepoint.fr/astronomie/trois-monstres-rouges-galactiques-debusques-dans-l-univers-jeune-defient-les-theories-15-11-2024-2575417_1925.php