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The James Webb Space Telescope (JWST) has discovered bright galaxies that exist in the early universe, which goes against current understanding of galaxy formation. These galaxies are surprisingly massive and shouldn't have had enough time to become so bulky in such early cosmic epochs. However, recent studies suggest that the unexpected girth of these galaxies could be due to astrophysical factors like earlier-forming black holes or bursts of star formation, rather than a flaw in our understanding of cosmology. Researchers are leaning towards this explanation rather than a fundamental flaw in our understanding of the expansion of the universe following the Big Bang.
Ever since it opened its giant infrared eye on the cosmos after its December 2021 launch, the James Webb Space Telescope (JWST) has found a shocking surfeit of bright galaxies that stretch back to the very early universe. Their brightnessa proxy for their numbers of stars and hence their massis deeply puzzling because galaxies shouldn't have had enough time to become so bulky in such early cosmic epochs.
Before the JWST, the Hubble Space Telescope held the record for the earliest galaxy ever found. However, the JWST has now surpassed that record and has observed galaxies even further back in time. These observations challenge current theories of galaxy formation and have led researchers to question if our understanding of cosmology is fundamentally flawed. Theorists initially wondered if there was something wrong with our understanding of the expansion of the universe following the Big Bang. However, recent studies suggest that astrophysical factors like the presence of earlier-forming black holes or bursts of star formation could explain the unexpected girth of these early galaxies.
Most people would put their money on the astrophysical explanation right now, says Mike Boylan-Kolchin, a cosmologist at the University of Texas at Austin. I'd count myself in that category as well.