This Is the Most Detailed Image Yet of the Milky Way’s Center

The European Space Agency’s (ESA) Euclid space telescope has captured the largest and most detailed visible-light image of the Milky Way’s galactic bulge to date, revealing more than 60 million stars in a single mosaic. This achievement, announced on March 23, 2025, provides a new resource for studying exoplanets and the structure of our galaxy, with implications for future space missions and astronomical research.

The image was acquired during a 26-hour observation campaign, consisting of nine separate exposures, each covering an area larger than the full moon. Euclid’s visible-light camera, designed primarily to observe distant galaxies, proved capable of resolving individual stars in the densely populated and bright galactic center, a task traditionally challenging for telescopes like Hubble due to its narrower field of view.

While Euclid was not optimized for the Milky Way’s center, its ability to capture such a detailed mosaic in a fraction of the time required by ground-based observatories marks a significant technical achievement. The image includes nebulae, star clusters, and known planetary systems, with 51 of these systems already identified as hosting planets. This new data will improve the measurement of planetary masses via gravitational microlensing, a technique that relies on observing star brightness variations caused by passing planets.

Although Euclid’s observational window was limited to 26 hours, it already provides a comprehensive snapshot of the stars involved in future microlensing events, serving as a valuable reference for upcoming missions such as NASA’s Nancy Grace Roman Space Telescope, scheduled to launch later this year. The data allows scientists to analyze the region’s stellar motions, dust, and other galactic features, extending its utility beyond exoplanet studies.

Why This Image Advances Galactic and Exoplanet Research

This achievement enhances our understanding of the Milky Way’s core, a densely populated and complex region that has been difficult to image in detail. The ability to resolve individual stars over such a large area in visible light opens new avenues for detecting and characterizing exoplanets through microlensing, which requires observing crowded stellar fields.

Moreover, Euclid’s image acts as a crucial reference archive for future missions, enabling more precise measurements of planetary masses and the dynamics of stars and dust in our galaxy. It also demonstrates the potential of Euclid’s instrumentation beyond its primary cosmological goals, broadening its scientific impact.

Background on Euclid’s Mission and Milky Way Imaging

Launched with the primary goal of studying dark energy and dark matter by observing billions of distant galaxies, the Euclid space telescope is equipped with a highly sensitive visible-light camera. Despite its main focus on the universe’s large-scale structure, Euclid’s capabilities extend to resolving individual stars in the Milky Way’s crowded center. This recent observation builds on prior efforts to image the galactic core, which has traditionally been challenging due to its brightness and density.

Previous ground-based and space telescopes, including Hubble and Keck, have captured parts of this region but with limitations in coverage speed and scale. Euclid’s ability to produce a mosaic covering an area 270 times larger than Hubble’s field of view in just hours marks a significant leap forward, enabling comprehensive surveys of the galactic bulge and its stellar populations.

“Euclid’s imaging capability allows us to resolve individual stars in the galactic bulge with unprecedented efficiency, opening new pathways for exoplanet detection.”

— an anonymous researcher

Remaining Questions About Euclid’s Milky Way Data

While the image provides a detailed snapshot of the galactic center, it does not include new exoplanet discoveries directly. The observation period was too short to detect new microlensing events, and ongoing analysis is needed to confirm and characterize additional planets. It is also unclear how Euclid’s imaging will integrate with other upcoming missions in terms of data sharing and combined analysis.

Further, the full scientific potential of the data, including detailed stellar motions and dust mapping, is still being evaluated, and researchers have not yet published comprehensive results beyond initial findings.

Next Steps for Euclid and Galactic Research

Scientists will analyze the Euclid data in detail to identify potential microlensing events and refine measurements of known exoplanets. The upcoming launch of the Nancy Grace Roman Space Telescope will enable cross-referencing of Euclid’s archive with real-time microlensing observations, enhancing the ability to discover and characterize new exoplanets.

Further observations and data processing are expected to expand the scientific returns, including detailed studies of stellar populations, dust distribution, and galaxy dynamics within our galaxy’s core.

Key Questions

What makes Euclid’s image of the Milky Way’s center so significant?

It is the largest and most detailed visible-light image of the galactic bulge ever taken, resolving over 60 million stars in a single mosaic, which advances exoplanet detection and galactic studies.

Will Euclid directly discover new exoplanets?

Not during this observation campaign; Euclid’s short-term data serves mainly as a reference. Future missions and analyses will focus on detecting microlensing events for new planet discoveries.

How does Euclid’s imaging compare to Hubble or Keck?

Euclid’s images have comparable quality to Hubble but cover a region 270 times larger in a fraction of the time, making it much faster and more efficient for wide-area surveys.

What are the implications for future galactic research?

The data provides a new baseline for studying the structure, stellar populations, and dust in the Milky Way’s core, supporting more precise models and future observations.

Source: WIRED