The James Webb Space Telescope has revolutionized our understanding of galaxy formation and evolution, providing unprecedented insights into the thick and thin disks that characterize many galaxies. By examining 111 single-disk and double-disk galaxies, including our own Milky Way, astronomers are uncovering how these celestial structures form and evolve over billions of years.
The discovery made possible by JWST revolves around the observation of disk galaxies as far back as 3.8 billion years after the Big Bang. This allows scientists to explore the origins of our galaxy’s structural components, bridging a crucial gap between high-redshift observations of the early universe and the study of our own galactic history.
Typically, disk galaxies contain a thick, star-filled outer disk and a thinner, embedded disk of stars. The Milky Way’s thick disk spans approximately 3,000 light years, while its thin disk measures around 1,000 light years in thickness. Understanding the formation pathways of these dual-disk structures is essential for unraveling galactic evolution.
JWST data reveals that galaxies tend to form a thick disk first, followed by a thin disk, with the timing influenced by the galaxy’s mass. High-mass galaxies transitioned to a two-disk structure about 8 billion years ago, whereas low-mass galaxies formed their thin disks much later, around 4 billion years ago.
The turbulent gas disk hypothesis suggests that a chaotic gas disk in the early universe sparks intense star formation, leading to the creation of a thick stellar disk. As stars form, they stabilize the gas disk, which then becomes less turbulent and thinner over time.
Future research plans include incorporating additional data into their edge-on galaxy sample, aiming to refine their understanding of disk formation and galactic evolution. The JWST continues to solve mysteries within our solar system and beyond, probing the origins of our universe and our place within it.
Source: https://www.rudebaguette.com/en/2025/06/james-webb-telescope-unlocks-the-deep-structural-secrets-of-disk-galaxies-revealing-how-the-universe-built-its-greatest-shapes