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European space Agency (ESA) Euclid Space Telescope It has captured the largest and most detailed visible light image ever milky way Galactic bulge, the central region of our galaxy.
The image is a mosaic containing more than 60 million stars as well as nebulae and star clusters. It will allow scientists to confirm the potential existence of exoplanets using microlensing technology and measure their masses more accurately.
Euclid’s power
Although Euclid was designed to observe billions of distant galaxies, its visible-light camera is sensitive enough to detect individual stars in the center of the Milky Way — an extremely bright, densely populated region — without being overwhelmed by intense light.
On March 23, 2025, Euclid turned its gaze toward the galactic bulge, capturing this massive image in just 26 hours of observations. The result was remarkable: a mosaic of nine separate “dots” (exposures) by the visible-light camera, each covering an area of sky larger than the full moon.
While the quality of Euclid’s visible light images is similar to that of… Hubble Space TelescopeThere is one key difference: Each point that Euclid captures in just a few hours covers an area 270 times larger than Hubble’s field of view. It’s also much faster. To put this into perspective, the Keck Observatory would require nearly 2,000 hours to observe the same mosaic.
Image of the Milky Way
The new Euclid image captures more than 60 million stars, along with nebulae and star clusters, in one of the Milky Way’s busiest regions, an ideal location for searching for exoplanets through gravitational microlensing.
“To observe microlensing, you need to observe parts of the sky crowded with stars, such as those near the center of our galaxy,” Jean-Philippe Beaulieu, who led the observing campaign, said in a report. press release. “In the past 20 years, nearly 300 exoplanets have been discovered using this technique, all using ground-based telescopes and all toward the center of our galaxy. This image from Euclid includes 51 known planetary systems, and will help study many more that will be discovered.”
Measuring planetary masses
Although detecting a microlensing event requires several weeks of observations – meaning that Euclid was unable to identify any new events during its relatively short observational campaign – what makes this image so valuable is that it provides the data needed to measure the masses of already known planets, as well as planets that have not yet been discovered.
“Within 24 hours, Euclid had already captured the stars participating in all future microlensing events that the Roman space telescope would detect, but before the stars and planets involved had aligned,” Natalia Rictsini, who led the data release, said in a press release. (The Nancy Grace Roman Space Telescope is scheduled to launch later this year.) “This means that anyone who detects a microlensing event in the same region, for example with Roman, will henceforth be able to use the Euclid data as a time reference in the past and see what the stars looked like before they overlapped.”
In fact, Euclid’s observations will serve as a reference archive for future missions, allowing for more detailed studies of exoplanets and more precise measurements of their masses.
“In just 24 hours, Euclid has provided unique data on the center of the Milky Way, with a large, sharp view of this region,” Valeria Pettorino, ESA’s Euclid project scientist, said in a press release. “This data can also be used in other scientific applications, from brown dwarfs and binary stars to stellar and dust motions across our galaxy.”
This story originally appeared on Wired Italy It was translated from Italian.
