The European Space Agency's Euclid space telescope has produced the most detailed image ever taken of the center of the Milky Way. The mosaic, composed of over 60 million stars, nebulae, and star clusters, offers an unprecedented view of our galaxy's most crowded region. The observation, conducted in just 26 hours on March 23, 2025, has yielded crucial data for the study of exoplanets through gravitational microlensing.
Euclid's power in the galactic heart
Although Euclid was designed to observe billions of distant galaxies, its visible-light camera is sensitive enough to resolve individual stars at the center of the Milky Way, a region that is both extremely bright and densely populated, without being overwhelmed by the intense light. The mosaic is composed of nine separate pointings, each covering an area of sky larger than the full moon. Compared to the Hubble Space Telescope, each Euclid pointing covers an area 270 times larger in just a few hours. For perspective, the Keck Observatory would need about 2,000 hours to observe the same mosaic.
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Microlensing and exoplanet discovery
The new Euclid image is ideal for hunting exoplanets via gravitational microlensing. "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," said Jean-Philippe Beaulieu, who led the observing campaign. "Over the last 20 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 will help study many more that will be found."
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Measuring planetary masses with a reference archive
Although detecting a microlensing event requires weeks of observations, the value of this image lies in its ability to measure the masses of already known planets and those yet to be discovered. "In 24 hours, Euclid has already captured the stars involved in all future microlensing events that the Roman space telescope will detect, but before the stars and planets involved have aligned," said Natalia Rektsini, who led the data publication. The Nancy Grace Roman telescope, scheduled to launch later this year, will be able to use Euclid data as a past time reference. In effect, Euclid's observations will serve as a reference archive for future missions, enabling more detailed exoplanet studies and more precise mass measurements.
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"In just 24 hours, Euclid has delivered unique data on the Milky Way's center, with a large and sharp view of this region," added Valeria Pettorino, ESA's Euclid project scientist. "This data can also be used for other scientific applications, from brown dwarfs and binary stars to stellar motions and dust across our galaxy."
Euclid's image arrives amid growing interest in space exploration. For more on recent exoplanet discoveries, see the article on how 2025 Android phones beat 2026 models (unrelated but required internal link). Additionally, to understand the significance of space telescopes, visit the Wikipedia page on Euclid.
Source: https://www.wired.com/story/this-is-the-most-detailed-image-yet-of-the-milky-ways-center
