On March 19, 2025, the European Space Agency’s Euclid mission unveiled a pivotal moment for astronomers and cosmologists worldwide. The much-anticipated release of its first batch of survey data provided a groundbreaking view into the universe’s distant reaches. Showcasing countless galaxies of various shapes and sizes, the data offered an unprecedented glimpse into the cosmic web’s expansive structure.
Today, I presented to @ESA Member States the first data from ESA's Euclid mission. This dataset includes 26 million galaxies, including a catalogue of more than 380 000 galaxies of which Euclid measured the shapes and the first catalogue of 500 galaxy-galaxy strong lenses,… pic.twitter.com/DNQQZWNmNQ
— Josef Aschbacher (@AschbacherJosef) March 19, 2025
This momentous release marks a new chapter in our understanding of the universe’s architecture, shedding light on the intricate organization of galaxies that has remained largely enigmatic until now.
The Euclid mission is designed to probe the dark universe, a term that encompasses the mysterious dark matter and dark energy. With this new data, Euclid takes a significant step forward in unraveling the nature of these elusive entities.
The data set extends across a sky area of about 63 square degrees, representing the largest contiguous area observed with an optical/near-infrared space telescope. This makes it seven times larger than previous releases, reflecting Euclid’s capacity to redefine the boundaries of space exploration.
‘For the first time, we are studying the cosmic web in a statistical way on a very large area, ‘ remarked Prof. Simona Mei, revealing the depth of insights Euclid is set to offer in cosmic evolution studies.
The impact of such a release cannot be underestimated. Beyond mapping the cosmos, the data has crucial implications for understanding how galaxies morph and align within cosmic structures across time. This monumental release is accompanied by thousands of galaxy filaments and newly discovered galaxy clusters, many dating back to the universe’s formative epochs.
The data is not only a treasure trove for cosmology but is invaluable for numerous non-cosmological studies, broadening knowledge in areas from galaxy clusters to smaller-scale astrophysical phenomena. Such advancements are made possible by Euclid’s high resolution and wide field of view capabilities, which are essential for such detailed surveys.
The mission’s first survey data includes more than 380, 000 galaxies and identifies 500 gravitational lens candidates. Carole Mundell, ESA’s director of science, emphasizes that Euclid is akin to a ‘dark universe detective, ‘ tracing the universe’s history back over 10 billion years.
To grasp the sheer volume of data collected, the information released amounts to 35 terabytes, equating to 200 days of high-definition video streaming. This analogy highlights the mission’s vast scope and the depth of its scientific contributions to date.
Euclid’s journey began with its launch in July 2023, which led to its start of routine observations by February 2024. It has already made significant strides with just a fraction of its capabilities, as evidenced by the discovery of an exceedingly rare Einstein ring, a phenomenon that occurs due to light bending around massive objects like galaxies.
Moreover, the mission has observed 26 million galaxies, some located as far as 10.5 billion light-years away. As Euclid continues its ambitious survey to 2030, it promises to map thousands more, opening new vistas in our quest to understand the universe.
Valeria Pettorino, Euclid’s project scientist, articulated the mission’s ambition: ‘It’s impressive how one observation of the deep field areas has already given us a wealth of data that can be used for a variety of purposes in astronomy.’ This endeavor, underscored by its innovative combination of artificial intelligence and global citizen science efforts, positions Euclid as a formidable force in scientific discovery.
This comprehensive exploration of galaxies and cosmic phenomena not only maps the universe but also enriches our knowledge, fostering scientific advancements for generations.
To sum up, the Euclid telescope, through its latest data release, provides an awe-inspiring insight into the distant galaxies and structures that form our universe. This step forwards in cosmic cartography is set to empower scientists worldwide with the tools to decode the universe’s grand blueprint, offering answers to profound cosmological questions.
