Over 60 million stars dazzle in new image of the Milky Way

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The European Space Agency’s (ESA) Euclid space telescope went to work in 2023 with a clear directive—scour the cosmos for dark matter and dark energy. But while these mysterious targets theoretically compose upwards of 95 percent of the entire known universe, there are still plenty of other subjects for the two-ton observer to examine.Over 60 million subjects, to be specific.

Astronomers recently directed Euclid to pause its normal duties and instead examine the Milky Way galaxy’s stunningly luminous interior, also known as a galactic bulge. The telescope’s visible-light camera sensitivity is on par with the Hubble Space Telescope’s wide-field lens, but with an exponentially larger vantage. In only a few hours, Euclid can image an area about 270 times larger than what Hubble can accomplish. The result is the sharpest visible light photo ever captured of the Milky Way core. The stellar image features more than 60 million stars as well as numerous stellar clusters and nebulae.

Two zooms show the staggering resolution of Euclid's image. The most zoomed-in vignette on the lower right corresponds to 0.003% of the galactic bulge survey area (which is 4.8 square degrees in total). With many thousands of stars discernible in this tiny area, the entire Euclid galactic bulge image charts no less than 60 million stars. Credit: ESA/Euclid/Euclid Consortium/NASA, CFHT, ESA/Gaia/DPAC, image processing by J.-C. Cuillandre and E. Bertin (CEA Paris-Saclay)
Two zooms show the staggering resolution of Euclid’s image. The most zoomed-in vignette on the lower right corresponds to 0.003% of the galactic bulge survey area (which is 4.8 square degrees in total). With many thousands of stars discernible in this tiny area, the entire Euclid galactic bulge image charts no less than 60 million stars. Credit: ESA/Euclid/Euclid Consortium/NASA, CFHT, ESA/Gaia/DPAC, image processing by J.-C. Cuillandre and E. Bertin (CEA Paris-Saclay)

The new photo is far more than a simple flex of Euclid’s power. The data contained inside is helping researchers understand otherwise hard-to-examine cosmic interactions like microlensing. A form of gravitational lensing, microlensing events only occur when two stars perfectly align in an observer’s line of sight. The star crossing in front of the other one brightens and bends the latter object’s light, thereby acting like a giant magnifying glass. The same situation also occurs for any nearby planets, allowing astronomers to identify otherwise invisible subjects.

“To catch microlensing, you need to observe parts of the sky that are crowded with stars, such as close to the center of our galaxy,” Jean-Philippe Beaulieu, a survey contributor from Institut d’Astrophysique de Paris, said in a statement.

Beaulieu explained that nearly 300 new exoplanets have been discovered using this method over the last 20 years, all through the use of telescopes here on Earth.

“This image from Euclid includes 51 known planetary systems—and it will assist in studying many more that will be found,” he added.

This infographic places Euclid’s galactic bulge survey in the broader context of the Milky Way’s structure, using data from ESA’s Gaia mission. The top row shows schematic views (artist impressions) of our spiral galaxy: an edge-on view highlighting the central bulge (top left), a top-down view revealing the spiral arms and the survey region (top centre), and a zoom into the galactic disc indicating the location of the Solar System (top right), from where Euclid observes the sky, which turns into the main background of the visual. The lower panel illustrates the diversity of objects captured by Euclid as it observed towards the galactic bulge in March 2025. Moving from left to right, the numbered cutouts highlight dense molecular clouds that obscure background starlight, a glowing emission nebula associated with recent star formation, a young star cluster, and finally the galactic bulge itself – a dense, spheroidal region containing ten billion stars. This crowded central region provides ideal conditions for detecting microlensing events. Credit: Euclid images: ESA/Euclid/Euclid Consortium/NASA, CFHT, image processing by J.-C. Cuillandre and E. Bertin (CEA Paris-Saclay); Milky Way artist impressions: ESA/Gaia/DPAC, Stefan Payne-Wardenaar)
This infographic places Euclid’s galactic bulge survey in the broader context of the Milky Way’s structure, using data from ESA’s Gaia mission. The top row shows schematic views (artist impressions) of our spiral galaxy: an edge-on view highlighting the central bulge (top left), a top-down view revealing the spiral arms and the survey region (top centre), and a zoom into the galactic disc indicating the location of the Solar System (top right), from where Euclid observes the sky, which turns into the main background of the visual. The lower panel illustrates the diversity of objects captured by Euclid as it observed towards the galactic bulge in March 2025. Moving from left to right, the numbered cutouts highlight dense molecular clouds that obscure background starlight, a glowing emission nebula associated with recent star formation, a young star cluster, and finally the galactic bulge itself – a dense, spheroidal region containing ten billion stars. This crowded central region provides ideal conditions for detecting microlensing events. Credit: Euclid images: ESA/Euclid/Euclid Consortium/NASA, CFHT, image processing by J.-C. Cuillandre and E. Bertin (CEA Paris-Saclay); Milky Way artist impressions: ESA/Gaia/DPAC, Stefan Payne-Wardenaar)

Spotting a new microlensing event typically takes over 20 days of examination, meaning Euclid’s 24-hour photo session can’t be used to find new examples. Instead, astronomers can begin assessing the mass of already known exoplanets while also preparing for yet-to-be-identified objects.

“In 24 hours, Euclid has already captured the stars involved in all the future microlensing events that the Roman Space Telescope will detect, but before the stars and planets involved have aligned,” added said survey contributor Natalia Rektsini. “This means that anyone who detects a microlensing event in the same region, for example with Roman, will be able from now on to use Euclid data as a time reference in the past and see how the stars looked before they overlapped.”

NASA is currently gearing up for the Roman Space Telescope’s launch in August 2026. Until then, there is still time to add your name to its cargo ahead of its journey into orbit.

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