The European Space Agency’s Euclid space telescope has produced the most detailed image to date of the densely populated center of the Milky Way, capturing a field containing 60 million stars. The image, unveiled Wednesday, offers an unprecedented view of the galaxy’s bright core and is expected to aid astronomers in the ongoing search and study of planets beyond the Solar System.
Located at the heart of the spiral galaxy is the galactic bulge, a densely packed region comprising billions of stars, explained French astronomer Jean-Charles Cuillandre, a member of the Euclid mission team. The telescope, positioned approximately 1.5 million kilometers from Earth, collected the image over a 26-hour period in March 2025 using its visible light camera. The final mosaic consists of nine separate photos, each covering an area larger than the full Moon. Although the raw images were captured in black and white, researchers enhanced the picture by integrating color data from the Canada-France-Hawaii Telescope in Hawaii.
Euclid was launched in 2023 with the primary scientific goal of mapping one-third of the sky to investigate the nature of dark matter and dark energy. While the recent focus on the Milky Way’s luminous center represents a deviation from this original mission, the telescope has proven highly effective in this application, Cuillandre noted.
Beyond its visual impact, the new image is valuable for planetary science through a technique known as microlensing. This phenomenon occurs when a foreground star passes in front of a background star, causing the light from the latter to bend and temporarily brighten. The gravitational influence of any planets orbiting the foreground star can produce subtle variations in this light curve, allowing astronomers to detect and measure exoplanets that might otherwise remain hidden.
Jean-Philippe Beaulieu, another French astronomer involved with Euclid, highlighted the significance of microlensing in exoplanet discovery. Over the past two decades, nearly 300 planets have been detected using this technique from ground-based observatories aimed toward the galactic center. Beaulieu recalled leading the team that identified an icy exoplanet resembling the fictional world of Hoth from Star Wars, discovered through microlensing about 20 years ago.
The current Euclid image incorporates data on 51 known planetary systems and is expected to facilitate detailed studies of many more as future discoveries emerge. While the image itself may not reveal new exoplanets directly, it provides a crucial resource for refining measurements and enhancing understanding of planetary populations within the crowded galactic bulge.