Observations by NASA’s James Webb Space Telescope (JWST) have led to the surprising discovery that an ancient, distant galaxy is not rotating as expected, adding to our knowledge of the diverse conditions of the early universe.
The recent JWST finding was especially unusual because similar behavior has been observed only in nearby, mature, massive galaxies whose star formation slowed gradually over billions of years.
A team of researchers estimates that the galaxy XMM-VID1-2075 is not even 2 billion years old, based on the JWST observations, compared to the Milky Way’s 13.6 billion years, making its behavior highly unusual, according to their recent paper published in Nature Astronomy.
Rotating Galaxies
“This one in particular did not show any evidence of rotation, which was surprising and very interesting,” said lead author Ben Forrest, a research scientist in the Department of Physics and Astronomy at the University of California, Davis.
As gas flowed into early galaxies, most astronomers believe that angular momentum, combined with gravity, caused them to spin. However, over long periods of time, galaxies can lose their initial spin through mergers rather than spins canceling one another out.
Because of this, we would expect to see this lack of spin primarily in galaxies close to Earth, as the distance light has traveled would be shorter, and therefore the light would come from older, more mature galaxies that have had the opportunity to experience such mergers. Finding a galaxy so distant, and therefore so young based on the speed of the light, is most unexpected.
James Webb Space Telescope Survey
The research was part of the MAGAZ3NE (Massive Ancient Galaxies at z>3 NEar-Infrared) survey on the JWST by researchers who had used Hawaii’s W.M. Keck observatory to observe XMM-VID1-2075 previously.
“Previous MAGAZ3NE observations had confirmed this was one of the most massive galaxies in the early universe, with already several times as many stars as our Milky Way, and also confirmed that it was no longer forming new stars, making it a compelling target for follow-up observations,” Forrest said.
Using the JWST’s advanced capabilities, the researchers compared XMM-VID1-2075 with two galaxies of similar age to measure their relative motion.
“This type of work has been done a lot with nearby galaxies because they’re closer and larger and so you can do these kinds of studies from the ground, but it’s very difficult to do with high redshift galaxies because they appear a lot smaller in the sky,” Forrest said. “(JWST) is really pushing the frontier for these kinds of studies.”
JWST DATA Reveals an Unusual Galaxy
The JWST data on the three galaxies yield a strange combination of results: one rotates as expected, another is described as “messy,” and the last does not rotate but exhibits significant random movement. While this behavior is expected of massive galaxies in our local neighborhood, the researchers were stunned to find it occurring so close to the beginning of the universe.
The team leans toward one possibility that may offer an explanation, suggesting that a kind of equilibrium was achieved when two galaxies with almost perfectly opposite rotations collided in a single event.
“For this particular galaxy, we see a large excess of light off to the side. And so that’s suggestive of some other object which has come in and is interacting with the system and potentially changing its dynamics,” Forrest said.
Continuing their work, the team will seek other early galaxies lacking spin and explore galaxy-formation simulations that could explain this behavior.
“There are some simulations that predict that there will be a very small number of these non-rotating galaxies very early in the universe, but they expect them to be quite rare,” Forrest concluded. “And so this is one way in which we can test these simulations and really figure out how common they are, and that can then give us information about whether our theories of this evolution are correct.”
The paper, “A Massive and Evolved Slow-Rotating Galaxy in the Early Universe,” appeared in Nature Astronomy on May 04, 2026.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.