Hubble Space Telescope Unveils Brilliance of Missing Globular Cluster

On July 16, 2025, the NASA Hubble Space Telescope revealed a previously unexplored globular cluster known as ESO 591-12, showcasing a captivating array of multicolored stars. This discovery contributes to the ongoing Hubble Missing Globular Clusters Survey, which aims to provide comprehensive observations of globular clusters located within the Milky Way galaxy.

Globular clusters, such as ESO 591-12, consist of tightly bound collections of tens of thousands to millions of stars, forming early in the history of galaxies in regions rich in gas and dust. These clusters typically maintain a similar age among their stars, as they originate from the same collapsing gas cloud. The new image captures distinct red and blue stars, indicating temperature variations, with red stars being cooler and blue stars being hotter.

According to Dr. Domenico Massari, an astrophysicist at the INAF - Osservatorio di Astrofisica e Scienza dello Spazio, "This observation is crucial for understanding the formation and evolution of globular clusters within our galaxy. Hubble's capabilities allow us to resolve individual stars in these dense clusters, something ground-based telescopes cannot achieve."

The Hubble Space Telescope has fundamentally transformed the study of these cosmic structures since its launch in 1990. With its ability to capture high-resolution images, researchers can analyze the ages and distances of globular clusters, thus gaining insights into the early stages of the Milky Way's formation. The mission specifically targets 34 confirmed globular clusters that have yet to be observed by Hubble.

In a statement, NASA Administrator Bill Nelson remarked, "Hubble continues to provide groundbreaking discoveries that deepen our understanding of the universe. Each new image captures not just beauty but also the story of the cosmos, inviting us to explore our place within it."

Globular clusters are believed to hold essential clues about the early universe and the processes that shaped galaxies. The data obtained from this survey will enable scientists to investigate the fundamental properties of unexplored clusters in the galactic bulge and halo, shedding light on the conditions that prevailed when these clusters formed. This is particularly significant as it informs our understanding of stellar evolution and the dynamics of galaxy formation.

As the Hubble Space Telescope continues its observations, the insights gleaned from ESO 591-12 will likely influence future research and exploration of globular clusters, offering a deeper comprehension of how galaxies, including our own, have evolved over billions of years. The findings underscore the importance of continued investment in space exploration, as each discovery paves the way for future scientific advancements.

Image credit: NASA, ESA, and D. Massari (INAF - Osservatorio di Astrofisica e Scienza dello Spazio); Processing: Gladys Kober (NASA/Catholic University of America).