Tens of thousands of galaxies glitter in first mosaics from Euclid Space Telescope

By Georgina Torbet Published March 19, 2025

Scientists working with the Euclid Space Telescope have released their first treasure trove of data, showing distant galaxies in deep field images of stunning detail. The telescope from the European Space Agency (ESA), launched in July 2023, is designed to study dark matter, the most mysterious substance in the universe. It does this by taking images across a huge portion of the sky, tracking the movements of galaxies on a large scale — which gives clues to dark matter’s presence through its gravitational effects.

In this first data release, scientists have shared three mosaics covering hundreds of thousands of galaxies, showing their many different shapes and sizes.

“Euclid shows itself once again to be the ultimate discovery machine. It is surveying galaxies on the grandest scale, enabling us to explore our cosmic history and the invisible forces shaping our Universe,” said Carole Mundell, ESA’s Director of Science.

The data release includes three large mosaics called deep field images, which are just initial previews of what to expect from Euclid in the future. The deep fields were gathered during a week of observations and cover 26 million galaxies up to 10.5 billion light-years away, plus many other bright objects in the sky.

“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: from galaxy shapes, to strong lenses, clusters, and star formation, among others,” said Valeria Pettorino, ESA’s Euclid project scientist. “We will observe each deep field between 30 and 52 times over Euclid’s six year mission, each time improving the resolution of how we see those areas, and the number of objects we manage to observe. Just think of the discoveries that await us.”

You can dive into the deep field images for yourself on ESA’s website, which hosts the Euclid Deep Field South mosaic, the Euclid Deep Field North mosaic, and the Euclid Deep Field Fornax mosaic.

With a projected mission aim to capture more than 1.5 billion galaxies over six years, and with the telescope generated around 100 GB of data per day, researchers will combine forces of human and AI capabilities to classify images of galaxies according to features like whether or not they have spiral arms.

A citizen science project called Galaxy Zoo has already seen nearly 10,000 human volunteers working to train an AI algorithm to categorize galaxies.