It would be older than Earth. The James Webb Telescope, which recently revealed its first photographs, may have found the most distant galaxy ever observed. The latter existed more than 13 billion years ago, compared to 4.5 billion for our blue planet.
The light from what has been named GLASS-z13 was actually emitted 13.5 billion years ago. This galaxy appears to us when it was only about 300 million years after the Big Bang, 100 million years shorter than the previously observed record, Rohan Naidu of the Center for Astrophysics at Harvard. He is the lead author of a study analyzing data from James Webb’s early observations, which is currently underway.
The study has not yet been peer-reviewed, but published as a “preprint” to be quickly available to the expert community. It has been submitted to a scientific journal for forthcoming publication, Rohan Naidu said.
To look far is to go back in time
One of the main tasks of the James Webb Telescope is to observe the first galaxies formed after the Big Bang, which took place 13.8 billion years ago.
In astronomy, looking far is like going back in time. For example, sunlight takes eight minutes to reach us, so we see it as it was eight minutes ago. By looking as far as possible, we can therefore perceive objects as they were billions of years ago.
“The records in astronomy are already faltering”
Many astronomers enthusiastically commented on this discovery on social networks.
“Records in astronomy are already faltering,” tweeted Thomas Zurbuchen, NASA associate administrator for science. “Yes, I tend to only applaud peer-reviewed scientific findings. But this is very promising!” he added of the study.
Another research team also concluded the same results, according to Rohan Naidu, which “gives him confidence”.
Already large galaxies shortly after the Big Bang
The galaxy was observed by James Webb’s NiRcam instrument and detected in what is called a “deep field,” that is, a wider image taken with a long exposure time to detect the faintest lights.
The special feature of James Webb is that it only works in the infrared. The light emitted by the oldest objects has stretched and “reddened” along the way, passing into this wavelength that is not visible to the human eye.
To draw a picture of this galaxy, the data has therefore been “translated” into the visible spectrum: it then appears as a red circular shape, rather fuzzy and white in the centre.
In fact, the twenty or so researchers who took part in the study studied two galaxies, the second one called GLASS-z11, which is less distant. They have surprising properties, given the little we already know:
They appear quite massive, and this very shortly after the Big Bang. It’s something we don’t really understand
Rohan Naidu, astronomer at the Harvard Center for Astrophysics
When exactly did they originate? Impossible to say at the moment. “There is still work to be done,” the researcher said. He and his colleagues requested more observing time with the telescope to perform spectroscopic analyses—a technique for determining the properties of a distant object through the analysis of captured light. This should confirm their distance.
The James Webb Telescope was launched into space about six months ago. Valued at $10 billion, it was placed 1.5 million kilometers from us. It has enough fuel to run for 20 years. Astronomers thus expect to be inundated with new cosmic discoveries for a long time to come.