James Webb telescope discovers the 4 oldest galaxies in the universe, born just 300 million years after the Big Bang

A sampling of thousands of galaxies of varying ages observed by the James Webb Space Telescope
A sampling of thousands of galaxies of varying ages observed by the James Webb Space Telescope (Image credit: ESA/Webb, NASA & CSA, A. Martel)

Astronomers using the James Webb Space Telescope (JWST) have just discovered the four most distant galaxies ever seen, located a little over 13 billion light-years from Earth. This means astronomers are seeing what galaxies looked like only 300 to 500 million years after the Big Bang, in the infancy of our now almost 14 billion-year-old universe, according to two new studies published April 4 in the journal Nature Astronomy.

"The frontier is moving almost every month," Pieter van Dokkum, a professor of astronomy at Yale University who was not involved in the studies, said in a commentary published in Nature Astronomy. There are now "only 300 million years of unexplored history of the universe between these galaxies and the Big Bang," van Dokkum added.

This may sound like familiar news, as several studies have recently claimed possible detections of even older galaxies using JWST in the past few months. The four newly discovered galaxies are different, though — astronomers have actually confirmed these are ancient galaxies and not some other celestial body, or a closer-by galaxy masquerading as a more distant one.

Related: James Webb Space Telescope discovers oldest black hole in the universe — a cosmic monster 10 million times heavier than the sun

Observations of the four oldest known galaxies in the universe, taken with the James Webb Space Telescope (Image credit: Nature Astronomy/ JWST)

For nearby galaxies, astronomers usually use color to estimate redshift, a parameter that describes distance as light waves stretch and turn redder while zooming across the expanding universe. However, this technique is a dicier choice when exploring wholly new frontiers like those being studied with JWST. In what van Dokkum describes as a "technical tour de force," the authors of the new research used detailed measurements of the galaxies' spectra, or the range of light they emit over different frequencies, to double-check the accuracy of the redshifts. 

These four galaxies exist in the epoch of reionization, a time when astronomers think the first stars were being created. Once they confirmed the galaxies' ages, the researchers sized up the galaxies’ stars, finding that they were quite small, at least compared with our Milky Way. But the galaxies were also creating stars at a fast pace — something that was "surprising so early in the universe," study co-author  Stéphane Charlot, a researcher at the Astrophysics Institute of Paris, told the French news agency AFP.

The galaxies also don't appear to contain any particularly complex elements, suggesting that their stars haven't yet had time to create heavier elements and are instead made of the original hydrogen and helium atoms from the early universe, according to the researchers.

"Galaxies had to grow up fast indeed," van Dokkum wrote, referring to the 300 million years in which these ancient galaxies formed. "To put this length of time in perspective, sharks have been around for longer!" 

When JWST launched in December 2021, astronomers hoped it would find the first galaxies — but results like these are showing that galaxies may have started earlier than anyone had previously thought. 

"The birth of the first galaxies may have been so early that it lies beyond even JWST's powers," van Dokkum wrote.

Briley Lewis
Freelance science writer

Briley Lewis (she/her) is a freelance science writer and Ph.D. Candidate/NSF Fellow at the University of California, Los Angeles studying Astronomy & Astrophysics. Follow her on Twitter @briles_34 or visit her website www.briley-lewis.com.

  • torenson
    These galaxies probably no longer exist.
  • Gnarmar
    I wonder how it is that you aren’t using your science brain? How can it be that you are being so ignorant to make such a claim about the age of galaxies in your title? For our scientists have not seen what is beyond these galaxies, nor have they proven that there is a boundary in this space of blackness that everything exists in. Tell me, are there more galaxies 230 trillion light years away? What if God told you there are 20 trillion more galaxies to be explored some day, after we are raised from the dead, and that they are all 230 trillion light years away? Seen? In science, it is folly to announce something as perfect when it has not been perfectly understood. These are what we “think” MIGHT be the oldest galaxies in our universe, but there could be much much more beyond what we see.
    “If ye are lovers of science, be scientific.”
    As a christian, I have heard a prophet declaring that the space we are in is actually infinite and the universe will expand forever, and we humans who were righteous , will see it all because we will never die. We will be able to explore every galaxy together in perfection without any sin, because God made it possible to teleport from one end of the universe to the other very immediately. This hasn’t been revealed to all people yet, it is not superstition, it has been absolutely revealed to some but “it cannot be discerned by the wise and prudent but it is only given to infants.” I say this in order to encourage you all to think of glorious and good things, as the evil spirits in this world always work to make us believe lies and to be depressed by them. Ask Jesus to show you what I am talking about, if you are humble and patient, you will see things that no human eye can see and you will hear things that human ears cannot hear.