Huge young galaxies spotted by JWST could flip our models of the universe

The galaxies detected by the James Webb Space Telescope appear too massive to form so early in the history of the universe, which could be a problem for our understanding of galaxy formation.

Many galaxies in the early universe appear much more massive than expected. Researchers using the James Webb Space Telescope (JWST) have discovered galaxies 100 billion times the mass of the sun that must have formed faster than current models can explain.

Ivo Labbe of the Swinburne University of Technology in Australia and colleagues have measured the distances of six massive galaxies using a phenomenon called redshift. Objects that are farther away from the Earth are moving away from us faster, so they appear redder than nearby objects. They found that all of these galaxies are about 30 billion light-years away, which means they formed within 700 million years after the Big Bang.

“I would imagine that galaxies like this would not have existed in the universe so early,” says Pieter van Dokkum of Yale University in Connecticut, a member of the research team. This is because all the galaxies had a mass of at least 10 billion times that of the Sun, and one of them weighed 100 billion solar masses. Based on models of galactic evolution, we expect such young galaxies to be relatively low-mass, without many stars, and then grow over time until they become more like our own Milky Way galaxy, which has a mass of about 1.5. trillion solar masses.

While these young galaxies are massive, they are also remarkably compact. “Maybe the centers of galaxies form very early, earlier than we thought, and then the rest of the galaxy builds up around them,” says van Dokkum. “I suspect we’re not looking at finished products, but undertakings that happened very quickly.”

The exact mechanism behind this “rapid” galaxy formation – or the formation of a galactic core, as it may be – remains to be seen. “If all this is confirmed by further research, then we will have to rethink part of the early history of the formation of galaxies,” says Andrew Ponzen from University College London.

Still, further investigation is critical, Ponzen and the researchers say. This follow-up will consist of detailed observations and analyzes of the light spectra of galaxies using the JWST, which van Dokkum says could take up to a year.

If these findings are confirmed, it could become a problem for our understanding of the universe as a whole, and not just the formation of galaxies. “After we submitted the paper, we were told that at that time there was not enough gas in the universe to form [as many massive galaxies as this study suggests] — and it was a bit shocking,” says Labbe. “If you shape these monsters and they contain more stars than the available gas in the universe, that’s a bit of a problem.” This may mean that we need to take a close look at our models of the early universe and its contents.