JADES-GS-z14-0 appears as a tiny dot in the constellation Fornax. (Image credit: ALMA (ESO/NAOJ/NRAO)/S. Carniani et al./S. Schowes et al./JWST: NASA, ESA, CSA, STScI, Brant Robertson (UC Santa Cruz), Ben Johnson (CfA), Sandro Tacchella (Cambridge), Phil Cargile (CfA))
Astronomers have discovered oxygen in the most distant galaxy known, changing ideas about the speed at which galaxies evolved.
The galaxy, named JADES-GS-z14-0, where the record-breaking discovery was made, formed at least 290 million years after the Big Bang and was first spotted by the James Webb Space Telescope (JWST) in 2024.
Heavy elements like oxygen are created in nuclear reactions in stars. Because the newly discovered oxygen existed when the universe was only 2% older than it is now, the element raises many questions among astronomers, as it indicates that stars in the early universe were born and died, spreading heavy elements into their environment much faster than previously thought. The results, by two different research teams, were published March 20 in two papers in Astronomy & Astrophysics and The Astrophysical Journal.
“It's like finding a teenager in a place where only babies are expected,” said Sander Schouws, a researcher at Leiden University in the Netherlands and lead author of the second study, in a statement. “The results show that the galaxy formed very quickly and is also evolving its characteristics very quickly, adding to the growing body of evidence that the process of galaxy formation is much faster than previously thought.”
The earliest oxygen
Astronomers can't say exactly when the first star clusters began to form into the galaxies we see today, but cosmologists previously estimated that the process started slowly, within the first few hundred million years after the Big Bang.
However, the discovery of JADES-GS-z14-0 and other similar galaxies challenges this assumption. The light detected by JWST's near-infrared spectrograph comes from a huge halo of young stars surrounding the galaxy's core, which have existed for at least 90 million years before the observation.
Young stars are typically made of hydrogen and helium, and they fuse these into heavier elements like oxygen as they age and break apart after their violent deaths. Around 300 million years ago, when we first observed JADES-GS-z14-0, astronomers expected that the universe was still too young to be abundant in heavy elements.
But after the Atacama Large Millimeter/submillimeter Array (ALMA) telescope in the Atacama Desert in Chile was aimed at the distant galaxy, researchers were amazed by what they found: JADES-GS-z14-0 had about 10 times more oxygen than expected.
“I was thrilled by the unexpected results because they opened up new insights into the early stages of galaxy evolution,” said Stefano Carniani, an astronomer at the Scuola Normale Superieure di Pisa in Italy and lead author of the first paper, in a statement. “The evidence that the galaxy had already reached maturity in the young universe raises questions about when and how galaxies emerged.”
How galaxies like JADES-GS-z14-0 were able to produce so many heavy-element-producing stars so quickly remains a mystery for future research. Astronomers currently speculate that this astonishing rapid enrichment of elements may be due to the early emergence of giant black holes; feedback from other stellar explosions; or dark energy, a mysterious force that is accelerating the expansion of the universe.
TOPICS James Webb Space Telescope
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