The Euclid space telescope turned its attention to the heart of the Milky Way for just one day, capturing a mesmerizing image filled with millions of stars crowded together in the galaxy’s bulge.
Launched in July 2023, the European Space Agency’s Euclid telescope is designed to observe the dark universe. On March 23, 2025, the telescope turned toward the light instead to image the bright inner region of the Milky Way, also known as the galactic bulge. In doing so, Euclid captured the largest high-resolution photo ever made of our galaxy’s center in visible light.
The above image, aside from being absolutely awe-inspiring, could also help scientists find exoplanets using a technique called microlensing.
Sky full of stars
The galactic bulge is the central region of the Milky Way, tightly packed with old, cooler stars. That gives the vast region its characteristic yellow color.
Euclid stared at the galaxy’s massive bulge from around 26,000 light-years away, capturing more than 60 million stars shimmering in crisp detail. The image was taken over 26 hours and was stitched together from nine pointings of Euclid’s visible light camera, each covering a patch of sky larger than the full Moon, according to ESA.
While Euclid’s sharpness and sensitivity in visible light are similar to the Hubble telescope’s wide field camera, each of its pointings spans an area 270 times larger than Hubble’s field of view. Due to its high sensitivity, Euclid is also able to capture details from faint stars that would otherwise be missed by ground-based telescopes.
The telescope’s visible light camera is sensitive enough to tell individual stars apart in the super-crowded galactic bulge without being blinded.
Euclid’s ultra-wide view of the galactic bulge captured more than just stars. The seemingly empty, dark patches in the image are dense, dust-rich molecular clouds that absorb and scatter light from the bulge behind them.
Finding new worlds
The recently released image can help astronomers search for exoplanets in the crowded region of the Milky Way and measure their mass using tiny changes in starlight over time.
Microlensing occurs when two stars happen to align with an observer, with the nearer star acting as a cosmic magnifying glass as it crosses in front of the other, bending and brightening the background star’s light. If there happens to be a planet in orbit around the nearer star, the planet’s gravity will also bend the light in a slightly uneven way. If scientists observe this small additional change in a star’s light, they know that a planet might be orbiting it.
“To catch microlensing, you need to observe parts of the sky that are crowded with stars, such as close to the centre of our galaxy,” Jean-Philippe Beaulieu, an astronomer at the Institut d’Astrophysique de Paris in France who co-led the exoplanet working group of the Euclid Consortium, said in a statement. “During the last twenty years, almost 300 exoplanets have been discovered using this technique, all with ground-based telescopes and all towards the center of our galaxy. This image from Euclid includes 51 known planetary systems—and it will assist in studying many more that will be found.”
Because Euclid only turned its attention to the galactic bulge for one day, the telescope did not capture any new microlensing events. The resulting image, however, could allow scientists to measure the mass of planets that are already known.
“In just 24 hours, Euclid has delivered unique data on the Milky Way’s centre, with a large and sharp view of this region,” Valeria Pettorino, Euclid’s project scientist at ESA, said in a statement. “With time, the separation between sources and lenses increases. That’s why this Euclid data will be a time reference for past and future missions and enable studies of exoplanets and their masses.”
