(ORDO NEWS) — The James Webb Space Telescope has discovered four of the most distant galaxies ever observed, one of which formed just 320 million years after the Big Bang, when the universe was still in its infancy.
The Webb Telescope, commissioned last year, has produced a spate of scientific discoveries, looking farther than ever into the far reaches of the universe, which also means it looks back in time.
By the light of time from the most distant galaxies reaches the Earth, it has been stretched by the expansion of the Universe and has shifted to the infrared region of the light spectrum.
The Webb Telescope’s NIRCam instrument has an unparalleled ability to detect this infrared light, allowing it to quickly detect a number of never-before-seen galaxies, some of which could change astronomers’ understanding of the early universe.
Galaxies date from 300 to 500 million years after the Big Bang over 13 billion years ago, when the universe was only two percent of its current age.
This means that the galaxies belong to the so-called “epoch of reionization”, the period when the first stars are believed to have appeared. The era came immediately after the cosmic dark ages caused by the Big Bang.
Marvelous
Stéphane Charlot, a researcher at the Paris Astrophysical Institute and co-author of two new studies, told AFP that the most distant galaxy, named JADES-GS-z13-0, formed 320 million years after the Big Bang.
This is the largest distance ever observed by astronomers, he said.
The Webb Telescope also confirmed the existence of JADES-GS-z10-0, which dates back 450 million years after the Big Bang and was previously discovered by the Hubble Space Telescope.
All four According to Charlot, the galaxies are “very small in mass” and weigh about one hundred million solar masses. The Milky Way is estimated to weigh 1.5 trillion solar masses.
But galaxies are “very active in star formation in proportion to their mass,” Charlot said.
These stars formed “at about the same rate as the Milky Way,” he added, a rate that was “surprising for the universe at such an early stage.”
The galaxies were also “very poor in metals”. he added.
This is consistent with the standard model of cosmology, the best scientific understanding of how the universe works, according to which the closer to the Big Bang, the less time remains for the formation of such metals.
Technical breakthrough
However, in February, the discovery of six massive galaxies 500–700 million years old after the Big Bang led some astronomers to question the standard model.
These galaxies, which were also observed with the Webb telescope, turned out to be larger than expected shortly after the birth of the universe. If this model is confirmed, an update to the standard model may be required.
Pieter van Dokkum, a research astronomer at Yale University who was not involved in the latest research, hailed the confirmation of four recently discovered distant galaxies as a “technical show of force.”
“The border moves almost every month,” van Dokkum. commented the journal Nature, adding that there is now “only 300 million years of unexplored history of the universe” between these galaxies and the Big Bang.
The Webb telescope observed possible galaxies. even closer to the Big Bang, but they haven’t been confirmed yet, he said.
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