Huge young galaxies seen by JWST may upend our models of the universe

The galaxy discovered by the James Webb Space Telescope is unbelievably huge for having formed so early in the history of the universe, which could pose a problem for our ideas about galaxy formation.

To Leah Crane and Alex Wilkins

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

Ivo Labbé and his colleagues at Swinburne University of Technology in Australia used a phenomenon called redshift to measure the distances to six massive galaxies. Objects farther away from Earth appear redder than closer objects because they are moving away faster. As a result, these galaxies are all about 30 billion light years away, meaning they formed within 700 million years of the Big Bang.

“I would have guessed that galaxies like this wouldn’t have existed in the early universe,” says research team member Peter Van Dokkum of Yale University in Connecticut. This is because all galaxies had a mass at least 10 billion times the mass of the Sun, and one of them is 100 billion times the mass of the Sun. Models of galactic evolution predict that young galaxies such as these will have relatively low mass, no stars at all, and grow over time to resemble our own Milky Way, which has a mass of about 1.5. Trillion solar masses.

These young galaxies are huge, but they’re also surprisingly compact. “The possibility is that the center of the galaxy formed very early, earlier than we thought, and the rest of the galaxy formed around it,” says van Dokkum. “I think what we’re seeing is not the finished product, but something that started very quickly.”

The exact mechanism behind this ‘rapid’ galaxy formation, or the exact mechanism of galactic core formation, remains to be elucidated. “If all this stands up to further investigation, I think we need to rethink some of the early history of galaxy formation,” said Andrew Ponzen of University College London.

But Ponzen and the researchers say further investigation is important. That follow-up will consist of JWST’s detailed observations and analysis of the galaxy’s optical spectrum, which van Dokkum says could take about a year.

If these findings persist, they could pose problems not only for our understanding of galaxy formation, but also for our understanding of the universe more generally. It was noted that there was actually not enough gas to form [as many massive galaxies as this study suggests] “And it was a little shocking,” Labbé says. , which may mean that we need to take a closer look at the model of the early universe and its contents.