The James Webb Space Telescope (JWST) continues to unveil the secrets of the cosmos with its latest discovery, an unusual “inside-out” galaxy observed just 700 million years post-Big Bang. This galaxy, known as JADES-GS+53.18343−27.79097, is not only a relic from the universe’s infancy but also challenges conventional ideas about galactic formation. Unlike the Milky Way and other familiar galaxies that grow from the inside out, this new galaxy exhibits a reverse growth pattern, forming stars more rapidly in its outer regions than in its dense core.
The JWST’s capability to penetrate cosmic dust and gas has confirmed what theoretical models long suggested—that inside-out galaxies were likely a norm in the early universe. These findings, recently published in Nature Astronomy, help us understand that the early universe may have hosted diverse galactic formation processes compared to what we see in our local universe.
Modern galaxies grow through star formation triggered by gas accumulation or by merging with other galaxies. However, the processes that dominated the cosmic youth remain a topic of active research. With the JWST, astronomers can now observe these early galaxies directly, gathering data that spans back to the first billion years of cosmic history. This not only provides a snapshot of the conditions soon after the Big Bang but also raises new questions about the evolution of galaxies over billions of years.
The “inside-out” galaxy in question possesses a dense core surrounded by a disk of rapidly forming stars. This rapid star formation is causing the galaxy to double in size approximately every 10 million years—a stark contrast to the Milky Way’s 10-billion-year doubling rate. As these new stars form, they gradually migrate toward the core, increasing the galaxy’s rotational speed.
This discovery opens the door to further investigations into other early-universe galaxies, enhancing our understanding of galactic growth cycles and their evolution into the structures observed today. Such research is crucial for piecing together the history and expansion of the universe.
For a deeper dive into the details of this discovery, visit the full article at Live Science.