Webb Telescope's Discovery of Massive Early Galaxies Still Defies Prior Understanding of Universe

Pennsylvania State University has an announcement. 'Six massive galaxies discovered in the early universe are upending what scientists previously understood about the origins of galaxies in the universe.'

'These objects are way more massiveâ than anyone expected,' said Joel Leja, assistant professor of astronomy and astrophysics at Penn State, who modeled light from these galaxies. 'We expected only to find tiny, young, baby galaxies at this point in time, but we've discovered galaxies as mature as our own in what was previously understood to be the dawn of the universe.'

Using the first dataset released from NASA's James Webb Space Telescope, the international team of scientists discovered objects as mature as the Milky Way when the universe was only 3% of its current age, about 500-700 million years after the Big Bang.... In a paper published February 22 in Nature, the researchers show evidence that the six galaxies are far more massive than anyone expected and call into question what scientists previously understood about galaxy formation at the very beginning of the universe. 'The revelation that massive galaxy formation began extremely early in the history of the universe upends what many of us had thought was settled science,' said Leja. 'We've been informally calling these objects 'universe breakers' — and they have been living up to their name so far.'

Leja explained that the galaxies the team discovered are so massive that they are in tension with 99% of models for cosmology. Accounting for such a high amount of mass would require either altering the models for cosmology or revising the scientific understanding of galaxy formation in the early universe — that galaxies started as small clouds of stars and dust that gradually grew larger over time. Either scenario requires a fundamental shift in our understanding of how the universe came to be, he added. 'We looked into the very early universe for the first time and had no idea what we were going to find,' Leja said. 'It turns out we found something so unexpected it actually creates problems for science. It calls the whole picture of early galaxy formation into question.'
'My first thought was we had made a mistake and we would just find it and move on with our lives,' Leja says in the statement. 'But we have yet to find that mistake, despite a lot of trying.'

'While the data indicates they are likely galaxies, I think there is a real possibility that a few of these objects turn out to be obscured supermassive black holes. Regardless, the amount of mass we discovered means that the known mass in stars at this period of our universe is up to 100 times greater than we had previously thought. Even if we cut the sample in half, this is still an astounding change.'

Phys.org got a more detailed explantion from one of the paper's co-authors:
It took our home galaxy the entire life of the universe for all its stars to assemble. For this young galaxy to achieve the same growth in just 700 million years, it would have had to grow around 20 times faster than the Milky Way, said Labbe, a researcher at Australia's Swinburne University of Technology. For there to be such massive galaxies so soon after the Big Bang goes against the current cosmological model which represents science's best understanding of how the universe works. According to theory, galaxies grow slowly from very small beginnings at early times,' Labbe said, adding that such galaxies were expected to be between 10 to 100 times smaller. But the size of these galaxies 'really go off a cliff,' he said....

The newly discovered galaxies could indicate that things sped up far faster in the early universe than previously thought, allowing stars to form 'much more efficiently,' said David Elbaz, an astrophysicist at the French Atomic Energy Commission not involved in the research. is could be linked to recent signs that the universe itself is expanding faster than we once believed, he added.

This subject sparks fierce debate among cosmologists, making this latest discovery 'all the more exciting, because it is one more indication that the model is cracking,' Elbaz said.

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