Euclidean Space Warp: Helps discover galaxies that bend space and time

Space-time distortions don’t just appear in sci-fi movies like Interstellar. In real life, we can see the distorting effects that gravity has on spacetime in the form of gravitational lenses.

The enormous gravitational pull of massive objects such as galaxies and galaxy clusters can distort the shape of space-time and bend light rays coming from distant galaxies behind them. By warping space-time, the foreground galaxy acts like a magnifying glass.

Light from background objects that are obscured no longer travels in a straight line. Instead, it bends around the intervening mass, often producing multiple images, stretched arcs, and even complete rings known as “Einstein rings” like the one recently discovered by Euclid.

Powerful gravitational lenses provide an impressive demonstration of Einstein’s theory of general relativity, showing that matter in the universe can act like a natural telescope, bringing distant objects into view.

ESA’s Euclid Telescope is revolutionizing the study of powerful gravitational lensing by providing extremely sensitive images in unprecedented detail over large areas of the sky. This is exactly what is needed to identify rare gravitational lenses.

In March 2025, 500 intergalactic strong lenses were discovered, located in the first 0.04% of the Euclidean data, most of which were previously unknown. This pioneering catalog was created through a collaboration of citizen scientists, artificial intelligence (AI), and researchers.

An early look at the new Euclid image.

As Euclid continues to explore and send around 100 GB of data to Earth every day, ESA and the Euclid Consortium are once again needing the help of citizen scientists to identify strong gravitational lenses in large datasets.

For this reason, the Space Warps team has launched a new Euclid image-based citizen science project that will be part of a future Euclid Data Release 1. Although this data is not yet publicly available, you can get an early glimpse of new images of galaxies captured by telescopes by participating in this new citizen science project.

This project examines new high-quality imaging data from Euclid, which harbors many previously unknown powerful lenses. Approximately 300,000 images are displayed, pre-selected by an AI algorithm. These images have been fine-tuned based on the results of the initial Citizen Science Euclidean Strong Lens Search. These are the top-ranked candidates out of DR1’s 72 million galaxies classified by an AI algorithm. Scientists expect this refined, high-quality data to reveal more than 10,000 new lenses.

What can we learn from powerful lenses?

The Euclid mission will primarily use two methods: weak lensing and baryon acoustic oscillations to investigate how the universe expanded and how its structure changed throughout the universe’s history. From this, scientists can learn more about the role of gravity and the nature of dark matter and dark energy.

Powerful gravitational lenses also provide insight into these central questions. For example, powerful lensing capabilities allow for the “weighting” of individual galaxies and galaxy clusters. This reveals the entire matter (dark or bright) and tracks the distribution of dark matter. By studying powerful lenses across cosmic time, scientists can track the expansion of the universe and its apparent acceleration. This provides further insight into the role of dark energy.

“At Space Warp, we have already seen the success of combining AI with visual inspection by citizen volunteers and scientists, efficiently finding hundreds of high-probability lens candidates during the first small-scale Euclidean search in 2024,” explains Arajita Verma, co-founder of Space Warp and project leader at the University of Oxford, UK.

“With this brand new DR1 data, we are 30 times larger than our original search and, when combined with improved AI algorithms, we expect to find more than 10,000 high-quality lens candidates. This is more than four times the number of lenses we have been able to find since the first gravitational lens was discovered nearly 50 years ago.”

This gradual change is possible thanks to Euclid. The mission will be able to map large areas of the sky with unique clarity, making it an ideal combination for finding unusual objects like powerful gravitational lenses.

“We can’t wait to see what we’ll find with this unprecedented data set. We invite you to join Space Warp and join us in this exciting exploration,” concludes Arajita.

About Euclid

Euclid was launched in July 2023 and began regular scientific observations on February 14, 2024. The mission’s goal is to uncover the hidden effects of dark matter and dark energy on the visible universe. Over six years, Euclid will observe the shapes, distances, and movements of billions of galaxies up to 10 billion light years.

Euclid is a European mission built and operated by ESA with donations from NASA. The Euclid consortium is comprised of more than 2,000 scientists from 300 institutions in 15 European countries, the United States, Canada, and Japan, and is responsible for providing scientific equipment and scientific data analysis. ESA selected Thales Alenia Space as the prime contractor for the construction of the satellite and its service module, while Airbus Defense and Space was chosen to develop the payload module, including the telescope. NASA provided NISP’s near-infrared spectrometer and photometer detectors. Euclid is a mid-class mission in ESA’s Cosmic Vision program.