James Webb telescope finds galaxies "too big to even exist"

An international team of researchers, led by Associate Professor Ivo Labbé from Swinburne University of Technology, have used the James Webb Space Telescope (JWST) to observe massive candidate galaxies at the beginning of time, believed to be up to 100 billion times the mass of the Sun. If confirmed, these galaxies would contain more mass than was thought to exist in the whole universe at that time.

The galaxies were identified using some of the first observations from the US$10 billion James Webb Space Telescope, which was launched in December 2021 and has been in operation since July 2022. The research was based on some of the first images taken by the JWST, with imaging processing by Dr Gabriel Brammer from the Niels Bohr Institute’s Cosmic Dawn Center at the University of Copenhagen. The results were published in the journal Nature.

“We’ve never observed galaxies of this colossal size, this early on after the Big Bang,” said Labbé, who was one of two Swinburne researchers leading projects awarded time in JWST’s first observation cycle.

“The six galaxies we found are more than 12 billion years old, only 500 to 700 million years after the Big Bang, reaching sizes up to 100 billion times the mass of our sun. This is too big to even exist within current models.

“This discovery could transform our understanding of how the earliest galaxies in our universe formed.”

Follow-up measurements are now being carried out to confirm the galaxies and rule out alternative explanations. According to Labbé, “One alternative, equally fascinating, is that some of the objects belong to a new class of emerging supermassive black holes, never seen before.”

If verified with spectroscopy, the findings will provide evidence to suggest that galaxies grew massive quicker than expected early in the history of the universe. Labbé concluded, “This initial discovery may just be the start of a transformation in how we make sense of the world around us.”

Image caption: A mosaic collected by James Webb of a region of space close to the Big Dipper, with insets showing the location of six new candidate galaxies from the dawn of the universe. Credits: NASA, ESA, CSA, I Labbé (Swinburne University of Technology). Image processing: G Brammer (Niels Bohr Institute’s Cosmic Dawn Center at the University of Copenhagen).