The huge mosaic released by ESA’s Euclid space telescope on October 15, 2024, accounts for 1% of the wide survey that Euclid will capture over six years. The location and actual size of the mosaic on the Southern Sky is shown in yellow. This all-sky view is an overlay of ESA Gaia’s star map from its second data release in 2018 and ESA Planck’s dust map from 2014. Credit: ESA/Euclid/Euclid Consortium/NASA; ESA/Gaia/DPAC; ESA/Planck Collaboration
A new 208-gigapixel cosmic map, capturing 132 square degrees of the Southern Sky, was unveiled, marking the start of a six-year journey by the Euclid mission to create the largest 3D cosmic map, revealing the universe in unprecedented detail.
The first section of Euclid’s map, a massive 208-gigapixel mosaic, was unveiled at the International Astronautical Congress in Milan, Italy, by ESA’s Director General Josef Aschbacher and Director of Science Carole Mundell.
This mosaic is composed of 260 observations taken between March 25 and April 8, 2024. In just two weeks, Euclid managed to capture 132 square degrees of the Southern Sky with incredible clarity—an area over 500 times larger than the full Moon.
Scope and Potential of Euclid’s Survey
This mosaic represents just 1% of the wide survey Euclid will complete over its six-year mission. The telescope will map the shapes, distances, and movements of billions of galaxies up to 10 billion light-years away, ultimately creating the largest 3D map of the cosmos ever made.
This first piece of the map already contains around 100 million sources: stars in our Milky Way and galaxies beyond. Some 14 million of these galaxies could be used to study the hidden influence of dark matter and dark energy on the Universe.[2]
This graphic provides an overview of the mosaic and zoomed in images released by ESA’s Euclid mission on October 15, 2024. On the top left, an all-sky map (41,000 square degrees) is visible with the location of Euclid’s mosaic on the Southern Sky highlighted in yellow. In the mosaic, the locations of the various zoomed in images are shown. Above the separate images, the zoom factor is given (from 3 to 600 times enlarged compared to the original mosaic). Credit: ESA/Euclid/Euclid Consortium/NASA, CEA Paris-Saclay, image processing by J.-C. Cuillandre, E. Bertin, G. Anselmi; ESA/Gaia/DPAC; ESA/Planck Collaboration
Capturing Cosmic Details
“This stunning image is the first piece of a map that in six years will reveal more than one third of the sky. 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,” says Valeria Pettorino, Euclid Project Scientist at ESA.
The spacecraft’s sensitive cameras captured an incredible number of objects in great detail. Zooming very deep into the mosaic (this image is enlarged 600 times compared to the full view), we can still clearly see the intricate structure of a spiral galaxy.
This mosaic made by ESA’s Euclid space telescope contains 260 observations collected between March 25 and April 8, 2024. This is 1% of the wide survey that Euclid will capture during six years. In just two weeks, Euclid covered 132 square degrees of the Southern Sky, more than 500 times the area of the full Moon as seen from Earth. The full mosaic is 208 gigapixels. Credit: ESA/Euclid/Euclid Consortium/NASA, CEA Paris-Saclay, image processing by J.-C. Cuillandre, E. Bertin, G. Anselmi
Features of the Galactic Mosaic
A special feature visible in the mosaic is dim clouds in between the stars in our own galaxy, they appear in light blue against the black background of space. They are a mix of gas and dust, also called “galactic cirrus” because they look like cirrus clouds. Euclid is able to see these clouds with its super sensitive visible light camera because they reflect optical light from the Milky Way. The clouds also shine in far-infrared light, as seen by ESA’s Planck mission.
This image shows an area of the mosaic released by ESA’s Euclid space telescope on October 15, 2024. The area is zoomed in 600 times compared to the large mosaic. In this image, a single spiral galaxy (called ESO 364-G036) is visible in great detail, 420 million light-years from us. This image shows 0.0003% of the initial image of 208 gigapixels, that is 1/330,000 of the area of the main Euclid mosaic. Credit: ESA/Euclid/Euclid Consortium/NASA, CEA Paris-Saclay, image processing by J.-C. Cuillandre, E. Bertin, G. AnselmiThis image shows an area of the mosaic released by ESA’s Euclid space telescope on October 15, 2024. The area is zoomed in 150 times compared to the large mosaic. On the left of the image, Euclid captured two galaxies (called ESO 364-G035 and G036) that are interacting with each other, 420 million light-years from us. On the right of the image, galaxy cluster Abell 3381 is visible, 678 million light-years away from us. Credit: ESA/Euclid/Euclid Consortium/NASA, CEA Paris-Saclay, image processing by J.-C. Cuillandre, E. Bertin, G. AnselmiThis image shows an area of the mosaic released by ESA’s Euclid space telescope on October 15, 2024. The area is zoomed in 36 times compared to the large mosaic. In this image, the core of galaxy cluster Abell 3381 is visible, 678 million light-years away from us. The image shows many different galaxies of various shapes and sizes, from massive elliptical to modest spiral galaxies, down to tiny and dim dwarf galaxies. Credit: ESA/Euclid/Euclid Consortium/NASA, CEA Paris-Saclay, image processing by J.-C. Cuillandre, E. Bertin, G. AnselmiThis image shows an area of the mosaic released by ESA’s Euclid space telescope on October 15, 2024. The area is zoomed in twelve times compared to the large mosaic. In the middle left, spiral galaxy NGC 2188 is visible edge-on at a distance of 25 million light-years. In the top right corner, galaxy cluster Abell 3381 is now clearly noticeable, 678 million light-years away from us. Credit: ESA/Euclid/Euclid Consortium/NASA, CEA Paris-Saclay, image processing by J.-C. Cuillandre, E. Bertin, G. AnselmiThis image displays an area of the mosaic released by ESA’s Euclid space telescope on October 15, 2024. The area is zoomed in three times compared to the large mosaic. This patch of the Southern Sky shows numerous stars in our own Milky Way, and many galaxies beyond. Thanks to its visible and infrared cameras, Euclid captures the stars in their various colors: red stars are colder, and white/blue stars are hotter. On the right of the image, galaxy cluster Abell 3381 is visible as a string of galaxies. Credit: ESA/Euclid/Euclid Consortium/NASA, CEA Paris-Saclay, image processing by J.-C. Cuillandre, E. Bertin, G. Anselmi
Preview and Future Plans for the Euclid Mission
This mosaic is a teaser for what’s to come from the Euclid mission. Since the mission started its routine science observations in February, 12% of the survey has been completed. The release of 53 square degrees of the survey, including a preview the Euclid Deep Field areas, is planned for March 2025. The mission’s first year of cosmology data will be released to the community in 2026.
This graphic shows the location of the fields on the sky that will be covered by Euclid’s wide (blue) and deep (yellow) surveys. The sky is shown in the Galactic coordinate system, with the bright horizontal band corresponding to the plane of our Milky Way galaxy, where most of its stars reside. Credit: ESA/Euclid/Euclid Consortium/NASA/Planck Collaboration/A. Mellinger – Acknowledgment: Jean-Charles Cuillandre, João Dinis and Euclid Consortium Survey Group
Notes
When we refer to distances in light-years, we refer to the time that the light has traveled in space to reach our telescopes (light travel time).
The 14 million galaxies are galaxies that are bright enough for Euclid to measure their distorted shapes (gravitational lensing) and learn more about the dark matter distribution in our Universe. Euclid’s map of the distribution of galaxies over cosmic time will also teach us about dark energy, which affects how quickly the Universe expands.
About Euclid
Euclid was launched in July 2023 and began routine science observations on February 14, 2024. The first glimpses of Euclid’s image quality were shared with the world in November 2023 and May 2024.
Euclid is a European mission led by ESA, with support from NASA. The scientific work is carried out by the Euclid Consortium, which includes over 2,000 scientists from 300 institutions across 15 European countries, as well as the USA, Canada, and Japan. The consortium is responsible for the mission’s scientific instruments and data analysis.
ESA selected Thales Alenia Space as the prime contractor for the satellite and service module, while Airbus Defence and Space developed the payload module, which includes the telescope. NASA contributed by providing the detectors for the Near-Infrared Spectrometer and Photometer (NISP). Euclid is a medium-class mission within ESA’s Cosmic Vision Program.
