James Webb finds a massive early-universe galaxy that does not rotate

A team of astronomers at the University of California, Davis, led by research scientist Ben Forrest, reported on 4 May 2026 in Nature Astronomy that they had used the James Webb Space Telescope (JWST) to detect a massive early-universe galaxy with no measurable rotation. The galaxy, catalogued as XMM-VID1-2075, formed less than two billion years after the Big Bang, an epoch in which, under the standard model of galaxy evolution, massive systems are expected to show a marked disc and clear rotation. According to the paper as published (DOI 10.1038/s41550-026-02855-0), the stars in this galaxy move randomly, a feature of older and more evolved systems much closer to the Milky Way.

The discovery matters because it disturbs the methodological balance of galaxy-formation models. Earlier studies, carried out mostly with Hubble and the W. M. Keck Observatory on Hawaii, had shown that massive early-universe galaxies have a sizeable disc shape and rotation that tracks the outer gravitational pull of the galactic core. The combination of mass and the absence of rotation in XMM-VID1-2075, lead author Forrest says, “is not impossible but it is not expected” and raises the question of whether the galaxy has been through a violent merger phase with another system that broke up the original disc.

Methodologically, the team used the NIRSpec spectrograph on the Webb telescope, which allows measurement of the velocities of different parts of a galaxy across wavelengths from 1 to 5 micrometres, the part of the spectrum where the stellar populations of highly distant objects are best resolved thanks to cosmological redshift. Spectroscopic measurements were taken of XMM-VID1-2075 and of two further comparison galaxies from the same epoch, which reduced the risk that the absence of rotation might be an artefact of instrument error or a particular orientation of the galaxy with respect to the observer.

What the result does not prove

Interesting as the result is, the authors explicitly warn in the conclusion about the limits of the study. A sample of three galaxies is too small to draw a conclusion about how many non-rotating massive systems existed in the early universe. Astrophysicists at the Max Planck Institute in Heidelberg, who were not involved in the research, told the science portal Space.com that a statistically meaningful conclusion would require a sample of at least 30 to 50 similar systems. That means the finding is consistent with an early galaxy-merger scenario but does not cause or prove it.

Second, the authors themselves acknowledge that this kind of study “has been done many times for galaxies near us, because they are closer and larger”, but that for galaxies at high redshift it is “very hard to do because they appear much smaller on the sky”. Further Webb observing runs, planned for the second half of 2026, are to widen the sample of galaxies in the same interval of cosmological age, which will permit more serious statistical analysis.

In practical terms, the discovery of XMM-VID1-2075 does not change the standing standard cosmological model (LambdaCDM), nor does it call into question the general understanding of galaxy formation. It rather suggests that the early universe held a greater diversity of galactic morphologies than earlier studies suggested, which is consistent with a string of Webb discoveries since 2023. According to ESA and NASA, the Webb telescope had completed more than 4,500 observing sessions by May 2026, about 30 percent of them in the field of distant galaxies.