Webb Makes Stunning Discovery About Chaotic Galaxies In Early Universe

James Webb Space Telescope (JWST) continues to peel back layers of our cosmic viewpoint: its latest discovery reveals that the youth of the universe was sometimes quite the jumbled mess. Astronomers have found that galaxies just a few hundred million years after the Big Bang were not the tidy, well-organized structures that current models sometimes predicted, but rather chaotic, turbulent messes that struggled to settle down.

For this study the team utilized JWST’s trusty NIRCam instrument in a specialized “grism mode,” which captures the faint light from ionized hydrogen gas. By measuring the movement of the gas, the group confirmed that most of these young galaxies were not rotating disks like our tranquil Milky Way, but were instead clumpy systems where gas was "puffed up and moving in all directions," according to first author Lola Danhaive of Cambridge's Kavli Institute for Cosmology.

Such turbulence is believed to be caused by two dominant forces: high-intensity star formation and frequent gravitational instabilities. The galaxies were growing up through a series of frequent mergers and bursts of star formation, which constantly injected energy and stirred up the gas, preventing the neat, ordered rotation seen in mature galaxies.

These new results help resolve a puzzle presented by some earlier, more limited JWST observations, which had spotted a few surprisingly massive, well-ordered disks at early times. By observing a much larger sample of galaxies, particularly those with lower stellar masses, the study provides a bigger picture that aligns better with theoretical predictions of the early cosmos.

Ultimately, this work captures a critical evolutionary phase, bridging the gap between the Epoch of Reionization (when the first stars and galaxies cleared the universe's primordial fog) and the so-called cosmic noon (when star formation peaked). The data shows that the building blocks of galaxies were truly toddler-like: restless, energetic, and prone to flailing. "This is just the beginning," said co-author Dr. Sandro Tacchella, noting that future studies will track how these volatile systems "grew up and became the graceful spirals" we see today.