Webb telescope discovers galaxy that may offer clues into Milky Way's birth

Named 'Firefly Sparkle,' this galaxy is distinguished by its low mass, offering a rare glimpse into early galaxy formation

NASA’s James Webb Space Telescope (JWST) has made a groundbreaking discovery, identifying a galaxy that existed just 600 million years after the Big Bang. This finding provides a rare opportunity to study the early Universe and offers insights into what the Milky Way might have looked like during its formative years.

 

Named “Firefly Sparkle,” this galaxy stands out due to its relatively low mass compared to others observed by the JWST. Researchers analysed 10 star clusters within the galaxy to better understand its formation and evolution. NASA shared on X (formerly Twitter): “Webb discerned distinct star clusters in the Firefly Sparkle galaxy, which existed 600 million years after the Big Bang — the first discovery of an actively forming galaxy as lightweight as the young Milky Way.”

 

 

A glimpse into early galaxy formation

 

Lamiya Mowla, co-lead author of the study and assistant professor at Wellesley College, told the BBC that resolving a galaxy from this era into distinct components was an unexpected achievement. Mowla noted the galaxy’s similarity in mass to the early Milky Way and its multiple phases of star formation, illustrating complex processes within a small structure.

 

Gravitational lensing: Key to discovery

 

The phenomenon of gravitational lensing played a critical role in unveiling the galaxy’s features. This effect magnified the light of Firefly Sparkle 16 to 26 times, making it visible to the JWST. Without gravitational lensing, the galaxy would have been undetectable.

 

The galaxy’s elongated shape, resembling a raindrop, indicates it is still forming. Mowla explained that Firefly Sparkle provides a rare glimpse of a galaxy being built piece by piece, unlike others where the “building blocks” are less apparent.

 

Insights into the Milky Way’s early history

 

Firefly Sparkle’s mass aligns with estimates for an early ancestor of the Milky Way. Researchers noted that each star cluster in the galaxy shows slight colour variations, with younger, hotter stars appearing blue and older stars taking on a reddish hue. This suggests stars formed at different times, reflecting various stages of star formation within a compact galaxy.

 

Two nearby galaxies, located 6,500 and 42,000 light-years away, could easily fit within the Milky Way, according to NASA. Researchers speculate that these neighbouring galaxies may influence Firefly Sparkle’s growth, triggering star formation as gas condenses and cools.

 

Yoshihisa Asada, a doctoral student at Kyoto University, told BBC that early galaxies likely expanded through repeated interactions and mergers with smaller galaxies.

 

Implications for galaxy evolution theories

 

The discovery supports theories that dense gas clouds in the early Universe collapsed into star clusters, which later merged to form larger galaxies. Conditions in the young Universe likely led to the creation of massive star clusters, driving the evolution of galaxies like the Milky Way.

 

“This observation reveals what galaxies like the Milky Way might have looked like when they were young,” Mowla said, underscoring the significance of Firefly Sparkle in understanding the origins of galaxy formation.