A surprising observation from NASA’s James Webb Space Telescope (JWST) has revealed a vestige of a galaxy that peeked through the early universe’s dense fog just 330 million years after the Big Bang. The recent sighting of ultraviolet light from this distant galaxy — called JADES-GS-z13-1 — has astonished researchers, shattering prior expectations of early galaxy formation.
Shortly after the Big Bang, the developing universe was clouded by a thick fog of neutral hydrogen, blocking the light emitted by galaxies. However, GS-z13-1 defied all odds and broke through the barrier with a wavelength of light known as a Lyman-alpha emission. Radiated by hydrogen atoms, the emission appeared much stronger than expected; astronomers are now trying to decipher where the radiation from this galaxy came from and what this could mean for continuing studies of the early universe.
James Webb Space Telescope Pins Redshift
The JWST’s Near-Infrared Camera (NIRc) and Mid-Infrared Instrument (MIRI) were instrumental in identifying the galaxy and estimating its redshift, which reflects its distance from Earth based on how its light is stretched out as it moves through ever-expanding space. Most galaxies are continuously moving away, and as they get farther out, the light they emit shifts toward longer wavelengths at the “redder” end of the electromagnetic spectrum.
Imaging from the JWST, as explained in a study published in Nature, pinned an initial redshift estimate of 12.9 for the galaxy, and further analysis yielded a more definitive redshift of 13.0; this figure indicates that the galaxy was observed at 330 million years after the Big Bang.
Read More: JWST Catches Lucky Alignment of the Cosmic Tornado and a Spiral Galaxy
Rethinking Reionization
Researchers, however, didn’t expect to see the prominent Lyman-alpha radiation that was captured along with the galaxy.
Much of the neutral hydrogen fog that permeated the early universe dissipated during a time called the epoch of reionization. As this period unfolded, the neutral hydrogen started to separate into ionized gas (due to light from early stars), causing the universe to become more transparent. The role of the Lyman-alpha radiation raises many questions for researchers, seemingly setting the initial stages of reionization to 330 million years after the Big Bang.
“We really shouldn’t have found a galaxy like this, given our understanding of the way the universe has evolved,” said co-author Kevin Hainline from the University of Arizona in a statement. “We could think of the early universe as shrouded with a thick fog that would make it exceedingly difficult to find even powerful lighthouses peeking through, yet here we see the beam of light from this galaxy piercing the veil.”
How Galactic Light Came to Be
Researchers are uncertain about the exact source of radiation from GS-z13-1, but they’ve drawn up a few theories. One possibility is that the light may have come from the earliest generation of stars formed in the universe, hotter and more luminous than stars formed in later epochs. Researchers say the light could also potentially have roots in a powerful galactic nucleus that was driven by one of the first supermassive black holes.
The research team is ready to uncover answers with additional observations of GS-z13-1, which could help shape entirely new perspectives of the early universe and how reionization brought sweeping changes.
Read More: Some Stars Are Born From Fluffy Clouds in the Early Universe
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
NASA. Cosmological Redshift
Nature. Witnessing the onset of reionization through Lyman-α emission at redshift 13
Center for Astrophysics. Preparing to Study the Epoch of Reionization
Jack Knudson is an assistant editor at Discover with a strong interest in environmental science and history. Before joining Discover in 2023, he studied journalism at the Scripps College of Communication at Ohio University and previously interned at Recycling Today magazine
