Astronomers Stunned by Ancient Galaxy With No Spin

Astronomers have uncovered an unexpected anomaly in the early universe: a galaxy from less than 2 billion years after the Big Bang that lacks rotation, a trait scientists assumed was universal in young galaxies. The galaxy, XMM-VID1-2075, was identified using the James Webb Space Telescope as part of the MAGAZ3NE survey, which previously observed it with the W.M. Keck Observatory in Hawaiʻi. Researchers found it contained several times more stars than the Milky Way but had already stopped forming new stars, making it unusually mature for its age. Galaxies typically spin due to gravity and inflowing gas, but XMM-VID1-2075 shows no organized rotation, challenging current models of galaxy formation. Lead author Ben Forrest of the University of California, Davis, noted that such 'slow rotator' galaxies are usually found much later in cosmic history, suggesting this one evolved unusually fast. Webb’s high-resolution observations revealed random star motion within the galaxy, similar to massive local galaxies that have undergone repeated collisions. The discovery raises questions about how XMM-VID1-2075 lost its rotation so early. One possibility is a major collision with another galaxy spinning in the opposite direction, canceling out its motion. Webb’s data showed an excess of light off to the side, which Forrest said could support this theory. The telescope’s ability to study high-redshift galaxies in detail was critical, as ground-based observations struggle with their small apparent size. The study, published May 4 in *Nature Astronomy*, highlights Webb’s role in pushing the boundaries of early-universe research. While two other galaxies from the same era showed expected rotation or irregular motion, XMM-VID1-2075’s lack of spin remains a puzzle. Researchers now aim to determine whether collisions, mergers, or other mechanisms caused its unique evolution.