ESA's Euclid Snaps First Images for Its Great Cosmic Atlas

The European Space Agency (ESA) has released the first “page” from Euclid’s cosmic atlas-in-progress. Although the images shared this week represent only 1% of what the atlas hopes to capture, they offer a breathtaking peek at the millions of stars and galaxies shining far beyond our solar system.

Dubbed the “dark universe telescope,” Euclid is the ESA’s attempt to map what’s otherwise known as the invisible part of the universe—that is, roughly 95% of it. With a majority of the universe’s mass consisting of dark matter and dark energy, the “dark universe” is vital to our understanding of how cosmic bodies came to be, are composed, and might evolve. With its 4-foot-long telescope, visible instrument (VIS), and near-infrared spectrometer and photometer (NISP), Euclid examines light from distant galaxies, allowing it to chart the three-dimensional distribution of matter throughout the vast universe. 

The ESA launched Euclid using a SpaceX Falcon 9 in July 2023. Since then, the observatory has sent us some incredible images of the Horsehead Nebula, globular clusters, stellar nurseries, and more. But while the ESA was busy showing off Messier 78 and the Dorado Group, it was also grabbing two weeks of observations from Euclid, which covered 132 square degrees of the Southern Sky between late March and early April 2024. Those observations gave the ESA what it would need to make the first pages of Euclid’s cosmic atlas.

In the corner of the above image lies an all-sky map composed of observations from the Gaia Planck observatories. The area highlighted in yellow shows which part of the Southern Sky Euclid was able to focus on earlier this year. This region, displayed as a mosaic next to the all-sky map, contains around 100 million light sources, including stars from our own Milky Way and galaxies hundreds of millions of light-years from Earth. According to the ESA, roughly 14 million of the galaxies spotted in this tiny section of Euclid’s atlas could be used to study the “hidden influence” of dark matter and dark energy on the universe.

“This stunning image is the first piece of a map that in six years will reveal more than one third of the sky,” said Valeria Pettorino, a project scientist on the Euclid mission. “This is just 1% of the map, and yet it is full of a variety of sources that will help scientists discover new ways to describe the universe.”

Credit: ESA/Euclid/Euclid Consortium/NASA, CEA Paris-Saclay, image processing by J.-C. Cuillandre, E. Bertin, G. Anselmi

In the sparkly image immediately above, Euclid captures interacting spiral galaxies from 420 million light-years away. The image at the top of this page meanwhile depicts the core of the Abell 3381 galaxy cluster, which is a whopping 678 million light-years from Earth.