James Webb Space Telescope reveals two of the oldest and most distant galaxies ever seen

The discovery offers a peek into the early stages of the universe.
Ayesha Gulzar
Two farthest galaxies seen to date captured by JWST.
Two farthest galaxies seen to date captured by JWST.

NASA, ESA, CSA, Tommaso Treu (UCLA) 

NASA's James Webb Space Telescope has captured two of the most distant galaxies that were hidden until now, including one that may have formed just 350m years after the big bang. These galaxies are far brighter than anyone expected, surprising astronomers who are struggling to figure out how stars and galaxies could have formed so rapidly after the big bang, which occurred 13.8 billion years ago.

"Everything we see is new. Webb is showing us that there's a very rich universe beyond what we imagined," said Tommaso Treu of the University of California at Los Angeles, principal investigator on one of the Webb programs.

The world's most advanced space telescope

James Webb Space Telescope is the most powerful space observatory ever launched from Earth. The telescope, with a giant segmented mirror, four sensitive cameras, and spectroscopic detectors operating at less than 50 degrees above absolute zero, is designed to uncover details of cosmic dawn never before observed.

James Webb Space Telescope reveals two of the oldest and most distant galaxies ever seen
An image from Webb telescope showing the distant galaxies

The galaxies in question are GLASS-z12, shining 350 million years after the Big Bang, and another dating back to 450 million years, discovered after just four days of analysis as part of the Grism Lens-Amplified Survey from Space, or GLASS, observing program.

Previously, the earliest galaxy observed was GN-z11, which existed 400 million years after the big bang and was spotted by the Hubble Space Telescope in 2016.

"These observations just make your head explode," Paola Santini, a co-author of a paper describing the discovery in the Astrophysical Journal Letters, said in a statement. "This is a whole new chapter in astronomy. It's like an archaeological dig, and suddenly you find a lost city or something you didn't know about. It's just staggering."

Galaxies from the depths of the cosmos

The galaxies discovered are surprising and unusual to astronomers. The two galaxies are incredibly distant, but they're also extremely bright. This means they could have been massive, with lots of low-mass stars, like later galaxies. Alternatively, they could be much less massive, consisting of far fewer extraordinarily bright stars.

The research findings have suggested that galaxies may have begun appearing in the universe just 100 million years after the big bang, which occurred 13.8 billion years ago. This timeline challenges astronomers' theories about how and when the first galaxies formed.

"We've nailed something that is incredibly fascinating. These galaxies would have had to have started coming together maybe just 100 million years after the big bang. Nobody expected that the dark ages would have ended so early," said Garth Illingworth of the University of California at Santa Cruz, a member of the team. "The primal universe would have been just one hundredth its current age. It's a sliver of time in the 13.8 billion-year-old evolving cosmos."

While all of this is very exciting, the ages of the newly discovered galaxies are not yet fully confirmed and require additional spectroscopic analysis. If confirmed, the discovery could change how astronomers understand galaxies and star formation in the universe's early days.

With Webb staring deeper into the cosmos, this discovery is just the beginning. The telescope is poised to throw the early universe wide open, giving us an unprecedented view into the dark and mysterious reaches at the beginning of, well, everything.

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