The James Webb Space Telescope located the most distant galaxy detected to date, created during the initial expansion of the Universe, just 320 million years after the
Big Bang,
according to studies published Tuesday.
The further away the galaxies are, and therefore younger,
the more difficult they are to detect
, since their light signal is very poor.
The first results from the James Webb Telescope (JWST), which began operating in July 2022, identified numerous "candidate" galaxies in the infrared spectrum, a wavelength invisible
to the human eye
that allows us to go back much further in time.
One of the previous images taken by the James Webb telescope of the Pandora cluster.
The Webb telescope has powerful infrared observation capabilities, which combined with spectroscopy, which analyzes light from an object to determine its chemical elements, located "unambiguously" the existence of four galaxies
.
All of them are located at the red end of the spectrum, that is, they are very far away, with an age ranging between 300 and 500 million years after the Big Bang (which occurred 13.8 billion years ago), according to two published studies. in
Nature Astronomy.
At that time, the Universe
was only 2% of its current age,
and it was going through what scientists call a reionization period: after the period known as the "dark ages", it became active again and began to produce a large amount of of stars.
The most distant galaxy located by the JWST, named
JADES-GS-z13-0,
formed "320 million years after the Big Bang" and its light is the most distant observed to date by astronomers, he explained to the AFP agency.
Stéphane Charlot of the Paris Institute of Astrophysics
, one of the study's authors.
Artist's rendering of the James Webb Space Telescope.
Photo Nasa- Beckwith
The space telescope also confirmed the existence of the galaxy GM-z11, some 450 million years after the Big Bang, and which had already been detected by the
Hubble telescope.
The four observed galaxies are very low-massive - barely a hundred million solar masses, compared to 1.5 trillion for the
Milky Way.
Instead, these galaxies are
"very active when it comes to forming stars
, in proportion to their mass", details this astrophysicist.
The formation of stars is taking place "at approximately the same rate as the Milky Way" a "surprising speed in that
initial stage of the Universe
", comments the researcher.
These galaxies are otherwise
"very metal poor"
, a discovery that confirms the usual theories of cosmology: the closer to the origin of the Universe, the less time these stars had to form complex molecules.
This new contribution from the JWST is
"a technological feat,"
says Pieter van Dokkum, an astronomer at Yale University, in a commentary attached to the study.
"Every month" the telescope exceeds "the frontiers of exploration," he explains.
In February, James Webb located a group of six galaxies 500 to 700 million years old after the Big Bang, apparently much more massive than expected.
If the existence of these galaxies were confirmed by spectroscopy, that could
call into question some of the theories about the formation of the universe.
