Euclid Telescope Captures Most Detailed Image Yet of Milky Way's Galactic Bulge

The European Space Agency's (ESA) Euclid space telescope has achieved a remarkable feat, capturing the largest and most detailed visible-light image ever obtained of the Milky Way's galactic bulge, the dense central region of our home galaxy. This monumental image, a mosaic encompassing over 60 million stars, along with numerous nebulae and star clusters, promises to revolutionize our understanding of exoplanets and stellar dynamics within this bustling cosmic neighborhood. While Euclid was primarily designed to survey billions of distant galaxies across the universe, its visible-light camera has proven exceptionally capable of resolving individual stars even in the Milky Way's incredibly bright and densely populated center. On March 23, 2025, the telescope turned its gaze towards the galactic bulge, meticulously collecting data over just 26 hours of observations. The result is a stunning mosaic composed of nine separate exposures, each covering an area of the sky larger than the full moon, demonstrating Euclid's unparalleled efficiency. What truly sets Euclid's achievement apart is its extraordinary field of view and speed. While the quality of its visible-light images rivals that of the venerable Hubble Space Telescope, Euclid's advantage lies in its expansive coverage. Each pointing by Euclid captures an area 270 times larger than Hubble's field of view, and it does so much faster. To illustrate, observing the same mosaic would demand approximately 2,000 hours of observation time from the ground-based Keck Observatory, highlighting Euclid's transformative capabilities in large-scale sky surveys. This new image is particularly valuable for the search and study of exoplanets through gravitational microlensing, a technique that requires observing crowded stellar fields. Jean-Philippe Beaulieu, who led the observing campaign, noted that nearly 300 exoplanets have been discovered using this method over the past two decades, primarily with ground-based telescopes. Euclid's image already includes 51 known planetary systems and will be instrumental in studying many more to be found. Although Euclid's relatively short observational campaign couldn't identify new microlensing events, the data it provides is crucial for precisely measuring the masses of both known and yet-to-be-discovered planets. Moreover, Euclid's observations are set to serve as an invaluable reference archive for future missions. Natalia Rektsini, who led the data publication, explained that Euclid has captured the stars involved in all future microlensing events that telescopes like the upcoming Nancy Grace Roman space telescope will detect, even before the stars and planets align. This means future researchers can use Euclid's data as a historical time reference, observing how stars appeared before gravitational lensing occurred. Beyond exoplanets, this rich dataset also holds potential for diverse scientific applications, from studying brown dwarfs and binary stars to stellar motions and the distribution of dust across our galaxy, as highlighted by ESA's Euclid project scientist, Valeria Pettorino.