The James Webb Space Telescope May Have Found The Oldest Galaxy Ever

Just a week after its first images were shown to the world, the James Webb Space Telescope may have discovered a galaxy that existed 13.5 billion years ago, a scientist analyzing the data said Wednesday.

Known as GLASS-z13, this galaxy dates back to 300 million years after the Big Bang, about 100 million years earlier than anything previously identified, Rohan Naidu of the Harvard Center for Astrophysics told AFP.

“We are potentially seeing the light of the most distant star that anyone has ever seen,” he said.

The further away the object is from us, the longer it will take for its light to reach us, and so gazing back into the distant universe is looking into the deep past.

JWST has the potential to break records, discovering galaxies that existed when the universe was only 300 million years old! Light from GLASS-z13 took 13.4 billion years to reach us, but the distance between us is now 33 billion light years due to the expansion of the universe! pic.twitter.com/5AcOBwHuO1

— Dr. James O’Donoghue (@physicsJ) 20 July 2022

Although GLASS-z13 existed in the early era of the Universe, its exact age is still unknown as it could have formed at any time within the first 300 million years.

GLASS-z13 is visible in so-called “preliminary release” data from the orbiting observatory’s main infrared imager, called the NIRcam – but the discovery was not revealed in the first set of images published by NASA last week.

When translated from infrared into the visible spectrum, galaxies appear as red clumps with white in the center, as part of a wider image of the distant cosmos called the “inner field”.

Naidu and colleagues – a team of 25 astronomers from around the world – have submitted their findings to a scientific journal.

For now, the research is posted on a preprint server, so it comes with the warning that the research has not yet been peer-reviewed – but it has sent the global astronomy community roaring.​

“The astronomical record is crumbling, and many more are shaky,” tweeted NASA chief scientist Thomas Zurbuchen.

“Yes, I tend to only cheer after the scientific results are clearly peer reviewed. But, this looks very promising,” he added.

Naidu said another team of astronomers led by Marco Castellano working on the same data had reached similar conclusions, “thus giving us confidence”.

‘Work to be done’

One of Webb’s great promises is his ability to discover the earliest galaxies that formed after the Big Bang, 13.8 billion years ago.

Because it is so far from Earth, by the time its light reaches us, it has been stretched by the expansion of the Universe and shifted into the infrared region of the light spectrum, which Webb is equipped to detect with unprecedented clarity.

Naidu and his colleagues combed through infrared data from this distant Universe, looking for signs of very distant galaxies.

Below a certain threshold of infrared wavelengths, all photons – energy packets – are absorbed by the neutral hydrogen of the Universe that lies between the object and the observer.

Using data collected through different infrared filters aimed at the same region of space, they were able to detect where this photon drop occurred, from which they infer the existence of this farthest galaxy.

“We searched all the initial data for galaxies with these very striking signatures, and these are the two systems that have the most interesting signatures by far,” said Naidu.

One is GLASS-z13, while the other, not ancient, is GLASS-z11.

“There is solid evidence, but there is still work to be done,” Naidu said.

Specifically, the team wanted to ask Webb’s manager for telescope time to perform spectroscopy – the analysis of light that reveals the nature of detail – to measure precise distances.

“Right now, our guesses for distance are based on what we don’t see – it would be great to have an answer for what we see,” Naidu said.

However, the team has detected a surprising trait.

For example, a galaxy is the mass of a billion Suns, which is “potentially very surprising, and that’s something we don’t really understand” given how quickly after the Big Bang it formed, Naidu said.

Launched last December and fully operational since last week, the Webb is the most powerful space telescope ever built, with astronomers confident it will mark a new era of discovery.

© Agence France-Presse

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