The James Webb Space Telescope has spotted the most distant galaxy ever discovered, which formed in the early ages of the universe, just 320 million years after the Big Bang, according to studies released Tuesday.
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The greater the distance between the galaxies, and therefore the younger, the more difficult it is to detect them due to the weaker their optical signals. The first relevance of the James Webb telescope (JWST), in service by July 2022, has been identifiable by the number of galaxies “candidates” in the infrared, a long-term invisible for the human eye and no observance permet de remonter loin in the past.
Its NIRCam imager’s powerful infrared vision, along with observations in spectroscopy that analyzes light coming from an object to determine its chemical elements, “unequivocally” confirmed the existence of four galaxies. They are all located towards the red end of the spectrum, and therefore very far away.
Their age: Between 300 and 500 million years after the Big Bang (which occurred 13.8 billion years ago), two studies published in Nature Astronomy detail. The universe was then only 2% of its current age, in the so-called reionization period: after the so-called Dark Ages period, it sort of ignited and began producing an enormous number of stars.
The most distant galaxy JWST has ever pushed out, called JADES-GS-z13-0, Stefan explained to AFP, may have formed “320 million years after the Big Bang”, and its light is the most distant that astronomers have ever observed. Charlotte, of the Astrophysical Institute in Paris, is one of the study’s authors.
The space telescope has also confirmed the existence of the galaxy GM-z11, dating from 450 million years after the Big Bang, whose existence the Hubble telescope detected.
The four observed galaxies are very low in mass — one hundred million solar masses versus, say, 1,500 billion in the Milky Way. But these galaxies are “very active in star formation, in proportion to their mass,” the astrophysicist details.
Star formation there would be “about the same rate as the Milky Way,” a speed that was “pretty surprising in the early Universe,” comments the NCRC researcher. Another lesson is that these galaxies are “very metal-poor,” a finding that aligns with the Standard Model of cosmology: the closer we get to the origins, the less time stars have to form these complex particles.
The JWST observation is a “technological powerhouse,” welcomes Pieter van Dokkum, an astronomer at Yale American University, in a commentary accompanying the study. He asserts that the telescope “almost every month is pushing the boundaries of exploration,” always going further into the universe.
Last February, an instrument developed by NASA spotted six galaxies between 500 and 700 million years after the Big Bang, which appear to be much larger than expected. If the existence of these galaxies is confirmed by spectroscopy, this could call into question part of the theory of the formation of the universe.
