James Webb Space Telescope keeps finding galaxies that shouldn’t exist, scientist warns

Six of the earliest and most massive galaxies that Nasa’s breakthrough telescope has seen so far appear to be bigger and more mature than they should be

The James Webb Space Telescope keeps finding galaxies that shouldn’t exist, a scientist has warned.

Six of the earliest and most massive galaxies that Nasa’s breakthrough telescope has seen so far appear to be bigger and more mature than they should be given where they are in the universe, researchers have warned.

The new findings build on previous research where scientists reported that despite coming from the very beginnings of the universe, the galaxies were as mature as our own Milky Way.

Now a new paper has appeared to confirm those findings, by “stress testing” the galaxies to better understand how they formed.

It suggests that, if scientists have not made a mistake, we may be missing some fundamental information about the universe.

“If the masses are right, then we are in uncharted territory,” said Mike Boylan-Kolchin, from the University of Texas at Austin, and the author of a new paper examining the unusual galaxies. “We’ll require something very new about galaxy formation or a modification to cosmology. One of the most extreme possibilities is that the universe was expanding faster shortly after the Big Bang than we predict, which might require new forces and particles.”

Professor Boylan-Kolchin’s paper, ‘Stress testing ΛCDM with high-redshift galaxy candidates’, has been published in Nature Astronomy this week.

It suggests that the information from the JWST proposes a profound dilemma for scientists. The data indicates that there might be something wrong with the dark energy and cold dark matter paradigm, or ΛCDM, that has been guiding cosmology for decades.

Usually, galaxies convert around 10 per cent of their gas into stars. But the newly discovered galaxies would have to be converting almost the entirety of it into stars.

That is theoretically possible. But it is a departure from what scientists would ever have expected.

Further observation of the galaxies should better clarify their ages and masses. It might show that the observations are incorrect: that supermassive black holes at their centre are heating the galaxies up, so they look more massive than they are, or that they are actually from a later time than expected but look older because of imaging problems.

But if they are confirmed, then astronomers may have to change their understanding of the cosmos and how galaxies grow, to adjust their model to account for the unusually large and mature galaxies.