The James Webb Space Telescope is rewriting our understanding of the universe by offering unprecedented views into galaxy formation and structure. Recent findings have shed light on the development of disk galaxies, including our own Milky Way.
Disk galaxies are characterized by their disk-like shapes, typically featuring a thick outer disk and thinner inner disk. The telescope’s ability to observe galaxies at various stages of development has brought us closer to understanding how these complex structures formed.
Researchers analyzed 111 edge-on disk galaxies, spanning back to approximately 2.8 billion years after the Big Bang, to uncover the mechanisms behind their evolution. This study marks the first time scientists have been able to distinguish between thick and thin disks across vast distances.
The team discovered that disk galaxies form their thick disk first, followed by the appearance of the thinner disk. The timing of this transformation depends on a galaxy’s mass, with high-mass galaxies transitioning earlier than low-mass galaxies.
Gas motion within these galaxies played a crucial role in explaining the difference in timing. The “turbulent gas disk” hypothesis suggests that turbulent gas sparked intense star formation, leading to the creation of a thick stellar disk. As stars formed, they stabilized the gas, causing the disk to calm down and become thinner.
Webb’s unmatched sensitivity allowed scientists to explore smaller and fainter galaxies from earlier epochs. For the first time, astronomers resolved thin stellar disks at high redshifts, discovering that thin disks were already in place as early as 8 billion years ago.
This groundbreaking study offers new insights into galaxy formation and has significant implications for our understanding of the universe’s evolution.
Source: https://dailygalaxy.com/2025/06/webb-telescope-birth-disk-galaxies