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The James Webb Space Telescope\u2019s infrared image of the galaxy cluster El Gordo<\/p>\n
NASA, ESA, CSA<\/p>\n<\/div>\n<\/figcaption><\/figure>\n<\/p>\n
Galaxies in the early universe have fewer metals than expected. Observations from the James Webb Space Telescope (JWST) show that these galaxies don\u2019t follow a fundamental rule about galaxy evolution that works in the relatively nearby \u2013 and therefore relatively recent \u2013 universe.<\/p>\n
Kasper Heintz at the University of Copenhagen in Denmark and his colleagues used JWST to look at 16 galaxies, all of which formed within the first 750 million years after the big bang. They found that these galaxies have fewer heavy elements, or metals as they\u2019re called in astronomy, than we\u2019d expect based on our understanding of closer galaxies.<\/p>\n
\u201cThe physics that drives galaxy formation and evolution at these early epochs must be drastically different than what we observe today,\u201d says Heintz. Some simulations predicted this phenomenon, and other observations hinted at it, but this is the first solid evidence.<\/p>\n
The observations suggest that these galaxies are diluted by pristine gas without metals in it. They\u2019re most likely born as we\u2019d expect: with metal abundances that are relatively, but not abnormally, low. Then they gobble up gas from the surrounding intergalactic material.<\/p>\n
This means these galaxies are not as independent of their surroundings as the ones we see in the nearby universe. \u201cIf we are to understand galaxy evolution at the earliest epochs, we can no longer treat them as individual \u2018ecosystems\u2019,\u201d says Heintz. \u201cWe have to take into account their intimate connection to the surrounding intergalactic or cirgumgalactic gas.\u201d<\/p>\n This isn\u2019t the first anomaly JWST spotted in early galaxies \u2013 the telescope also found that they are far more massive and abundant than we had expected. The new observations might actually make the problems with our understanding worse, because the huge amounts of gas required to dilute early galaxies would make them even more shockingly massive.<\/p>\n Topics:<\/p>\n