NASA’s James Webb telescope has made a groundbreaking discovery, spotting a 13 billion-year-old galaxy that defies our current understanding of the universe. The galaxy, named ZF-UDS-7329, is larger than the Milky Way, which scientists previously believed was impossible for that early in the universe’s history. This observation could revolutionize our knowledge of how dark matter shaped the early universe.
For years, scientists have been tracking ZF-UDS-7329, but they were never able to get a close enough look until now. With the James Webb Space Telescope, they were finally able to peer into the galaxy about 11.5 billion years in our past. This is because light travels at a fixed speed through space, so the image of these early galaxies is only reaching us now.
What the team discovered was astonishing. ZF-UDS-7329 appeared much more advanced than previously thought possible. It contained about four times as many stars by mass as the Milky Way and these stars appeared to be ancient, approximately 1.5 billion years old. This suggests that the galaxy itself is around 13 billion years old.
This finding challenges current cosmology models because dark matter, which makes up more than 80% of the universe, was not expected to have been mature enough at that time. The leading theory is that an ocean of dark matter filled the early universe after the Big Bang. Dark matter is still a mystery to scientists, as they don’t fully understand what it is or have directly observed it. However, they can detect its presence by observing how it distorts light around the universe.
According to astrophysicist Ivo Labbe of Swinburne University of Technology, dark matter started out smooth with tiny ripples. Over time, these ripples grew due to gravity and eventually formed concentrated clumps, dragging hydrogen gas along with them. However, the galaxy discovered by the James Webb telescope should not exist under this model.
This discovery is not an isolated case. Scientists have previously found an 11.7 billion-year-old barrel galaxy, billions of years earlier than expected. These extremely massive galaxies challenge our standard model of cosmology and raise questions about how galaxies form and evolve.
One puzzling aspect of ZF-UDS-7329 is that it appears to have become quiescent, not continuing to evolve like other galaxies. This raises the question of how these galaxies form so quickly in the early universe and what mechanisms prevent them from forming stars abruptly when the rest of the universe is doing so.
While this discovery is significant, Karl Glazebrook, the astronomer who led the team, cautions against throwing out the current model altogether. More evidence is needed to confirm these observations and determine if they are generalizable. However, if more galaxies like ZF-UDS-7329 are found, it could truly disrupt our understanding of galaxy formation.
The team published their findings in the peer-reviewed journal Nature on February 14. This discovery marks a new record and opens up exciting possibilities for further exploration and understanding of the early universe.