ESA’s Euclid captures the Milky Way’s crowded heart
Article excerpt
Video: 00:03:00 This is the largest high-resolution photo ever made of our Milky Way galaxy’s centre in visible light. It was taken on 23 March 2025 by the European Space Agency’s Euclid space telescope. Packed with more than 60 million stars, this image opens the door for scientists to confirm the existence of any exoplanet found in this region and measure its mass using tiny changes in starlight over time.
The galactic bulge, the central region of our galaxy, is a vast, tightly packed structure filled mainly with old, cooler stars, giving it its characteristic yellow colour. Seen from some 26 000 light-years away, Euclid observes the galaxy’s centre through a complex foreground of material along its line of sight.
This ultra-wide view towards the bulge reveals not only stars, but also seemingly empty dark regions. The dark patches are not devoid of stars: they mark dense, dust-rich molecular clouds that absorb and scatter light from the bulge behind them. As Euclid looks through two of the Milky Way’s spiral arms, it also encounters regions of active star formation, traced by newly formed, massive blue stars. Their intense ultraviolet radiation ionises surrounding hydrogen gas, producing the faint red glow.