An international team of astronomers has announced an incredible discovery: the two earliest and most distant galaxies ever seen, dating back to only 300 million years after the Big Bang.
This discovery, made possible by NASA’s James Webb Space Telescope (JWST), marks a significant milestone in our understanding of the early universe.
The team behind this discovery is part of the JWST Advanced Deep Extragalactic Survey (JADES).
Daniel Eisenstein, a professor at Harvard University and a leader of JADES, played a key role in the program that revealed these galaxies.
Other important contributors include Ben Johnson, Phillip Cargile, and Zihao Wu from Harvard’s Center for Astrophysics.
Because the universe is expanding, the light from distant galaxies stretches to longer wavelengths as it travels.
For these two galaxies, this means their ultraviolet light has shifted to infrared wavelengths, which only the JWST can detect.
Since light takes time to travel, observing distant galaxies also means looking back in time.
The two newly discovered galaxies are named JADES-GS-z14-0 and JADES-GS-z14-1. JADES-GS-z14-0 is the more distant and more remarkable of the two.
Its large size and brightness indicate that it is full of young stars rather than material falling into a supermassive black hole.
“The size of the galaxy clearly proves that most of the light is being produced by large numbers of young stars,” said Eisenstein. This makes JADES-GS-z14-0 a striking example of rapid galaxy formation in the early universe.
Dr. Stefano Carniani, a lead author of the discovery paper, noted, “It is stunning that the universe can make such a galaxy in only 300 million years.” This finding challenges previous theories about how quickly galaxies could form after the Big Bang.
When the JADES team first spotted JADES-GS-z14-0 over a year ago, they were unsure if it was a distant galaxy or just a neighbor to a closer one.
In October 2023, they conducted even deeper imaging with the JWST, using special filters to isolate the earliest galaxies.
“We just couldn’t see any plausible way to explain this galaxy as being merely a neighbor of the more nearby galaxy,” said Dr. Kevin Hainline from the University of Arizona.
The galaxy’s brightness at intermediate infrared wavelengths suggests it is already creating elements like hydrogen and oxygen, even though it is so young.
“Despite being so young, the galaxy is already hard at work creating the elements familiar to us on Earth,” said Zihao Wu, a co-author on a related paper.
The team then obtained a spectrum of each galaxy, confirming that JADES-GS-z14-0 was indeed a record-breaking galaxy and that JADES-GS-z14-1 was nearly as far away.
“This amazing object shows that galaxy formation in the early universe is very rapid and intense,” said Ben Johnson. “JWST will allow us to find more of these galaxies, perhaps when the universe was even younger. It is a marvelous opportunity to study how galaxies get started.”
All three papers on this discovery are available on the arXiv preprint server. This breakthrough opens new doors for understanding the formation and evolution of galaxies in the early universe.
