Euclid Telescope Captures Unprecedented View of Milky Way's Galactic Center

The European Space Agency's Euclid space telescope has produced the largest and most detailed visible-light image of the Milky Way's galactic bulge, revealing over 60 million stars and opening new avenues for exoplanet research.

Image Details and Observations

The observation was conducted on March 23, 2025, over approximately 26 hours. The final 60-gigapixel mosaic is composed of nine separate exposures, each covering an area larger than the full moon.

Euclid's visible-light camera delivers a resolution similar to the Hubble Space Telescope but covers roughly 270 times the field of view per observation. The region imaged lies approximately 26,000 light-years away in the constellation Sagittarius.

The mosaic reveals not only the vast sea of stars but also nebulae and star clusters, providing an unprecedented census of the galactic center.

Application to Exoplanet Detection

The high stellar density of the galactic bulge makes it a prime target for detecting exoplanets using gravitational microlensing. This technique relies on the chance alignment of two stars, where the gravity of a foreground star bends and magnifies the light of a background star. A planet orbiting the foreground star can cause a subtle additional change in brightness.

While no new microlensing events were captured during the 26-hour observation—detecting them typically requires about 20 days of continuous monitoring—the data provides a crucial baseline reference of stellar positions and motions for future studies.

According to members of the Euclid consortium, the image includes 51 known planetary systems and the host stars for two known cold exoplanets: OGLE-2005-BLG-390Lb and OGLE-2013-BLG-341Lb. The data is expected to assist in measuring the masses of approximately 60 previously discovered exoplanets in the region.

Related Missions

NASA's Nancy Grace Roman Space Telescope, scheduled for launch on August 30, 2025, is expected to observe the same region for longer periods to detect microlensing events.

Euclid's images will provide a time reference for past stellar positions, which can improve microlensing measurements for the Roman Space Telescope by up to a factor of three.

Scientific Context

According to ESA Euclid Project Scientist Valeria Pettorino, the data is also applicable to other scientific fields, including the study of brown dwarfs, binary stars, stellar motions, and dust distribution across the galaxy.

The Euclid telescope, launched in 2023 on a €1 billion mission, is primarily designed to create a 3D map of the universe to study dark energy and dark matter. This galactic center observation represents a valuable scientific byproduct of its primary mission.