ESA’s Euclid telescope releases its first major cosmic map: 900 million galaxies, and that’s only 14%

The night sky can look empty to the naked eye. A new cosmic survey argues the opposite: if a telescope is wide enough and sharp enough, galaxies turn up by the hundreds of millions.

At 19:00 Beijing time on Nov. 12, 2026 (6:00 a.m. EST), the European Space Agency released the first major batch of data from its Euclid space telescope. The package is called DR1-Foundation. ESA’s science account posted at the same moment, calling it the “dark Universe detective’s” biggest case file yet. The data come from about 13 months of observations and cover an area of sky as large as 9,500 full Moons as seen from Earth — about 1,900 square degrees — totaling about 1.7 million GB. ESA Director of Science Carole Mundell said the images are “far more than beautiful pictures” and called the release a scientific milestone and the largest space-based survey of its kind.

Those 1.7 million GB, or about 1.7 petabytes, would overflow a house full of ordinary hard drives. The more useful way to read the number is what is inside. ESA says the release includes more than 900 million galaxies; about 15,000 candidates for strong gravitational lenses; more than 60 million quasar candidates; and spectra for more than 160 million sources. A quasar is a short, extremely bright chapter in a massive galaxy’s life, when material swirling into a central black hole throws off intense light. A spectrum is the light of a galaxy split into a rainbow, which lets scientists estimate how far away it is and, for the brighter ones, what it is made of.

Euclid launched in July 2023 and began routine science observations on Feb. 14, 2024. Its job is not a handful of pretty close-ups. It is to build a deep 3D map of the Universe and, with that map, to study dark matter and dark energy — the invisible mass and the still-unexplained push that appear to shape how the cosmos is built and why its expansion is speeding up. Gravitational lensing is one of the few ways to weigh that hidden mass. When light from a distant galaxy passes a massive galaxy in the foreground, gravity can bend and magnify it into arcs or multiple images. Strong lenses are rare: only about one galaxy in several thousand acts as a lens. ESA says this catalog is the largest ever assembled, bigger than all previous strong-lens catalogs combined. Finding them took machine learning and thousands of volunteer “citizen scientists” who combed Euclid images through the Space Warps project on Zooniverse. Natalie Lines of the University of Portsmouth, a Euclid Consortium member, said the team forecast more than a decade ago that Euclid would change strong-lens discovery: “That day is finally here.”

It is still an opening chapter. Euclid project scientist Valeria Pettorino noted that earlier public releases covered only a few days of observing over about 60 square degrees. This one covers more than a year and a much larger patch of sky — and even so, only about 14% of the area Euclid is expected to survey. The full Data Release 1 is scheduled for mid-2027 and will add the subtler “weak lensing” measurements and a clearer picture of how galaxy clusters sit in the cosmic web. For everyday readers, the release will not change a phone app tomorrow. It is a foundation other research will stand on. The data are already available through the Euclid Data Space, and over the next couple of years, many attempts to explain why the Universe looks the way it does will start from this map.

Original sources published: European Space Agency, Nov 12, 2026, 19:00 Beijing time / 6:00 AM EST; ESA Science (X), Nov 12, 2026, 19:00 Beijing time / 6:00 AM EST; The Guardian, Nov 12, 2026, 19:08 Beijing time / 6:08 AM EST