They were found independently by two teams, one led by Rohan Naidu, now at the Massachusetts Institute of Technology, and the other led by Marco Castellano of the Astronomical Observatory of Rome in Italy. Dating back to 350 million and 450 million years after the big bang, at the time of their discovery, both galaxies were older than any others known before. Now two of JWST’s most tantalizing candidate early galaxies have stood up to further scrutiny, strengthening scientists’ suspicions that our knowledge of cosmic history is crucially incomplete. Explaining this excess may require substantial revisions to prevailing cosmological models, changes that could involve the first galaxies forming sooner, their stars shining brighter-or perhaps the nature of dark matter or dark energy being even more complex and mysterious than previously thought. Simply put, candidate galaxies in the early universe are popping up in numbers that defy predictions, with dozens found so far. But its haul of galactic “baby pictures” has proved more bountiful than most researchers dared to dream. Designed to glimpse the faint infrared glow of the universe’s earliest luminous objects, JWST’s vision reaches back into the first few hundred million years after the big bang, allowing it to obtain more and better data about newborn galaxies than any other facility yet built. That’s the almost inescapable conclusion from initial observations by the James Webb Space Telescope (JWST), the $10-billion observatory that began science operations in July.
In their quest to understand the first stars and galaxies that lit up the cosmos, astronomers are still in the dark-but getting closer to enlightenment one discovery at a time.
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