UK science uncovers mysteries of dark universe with Euclid data
Source: gov.uk (2025-03-19)

Cutting-edge UK research is benefiting the European Space Agency’s Euclid mission, with new data released today (19 March) set to uncover the secrets of dark energy and matter.

The wealth of new data from the mission – described as the ultimate discovery machine – includes details of 500 galaxies that seem to experience a phenomenon known as strong lensing.

This is where light from more distant galaxies is bent around closer galaxies due to gravity, like how light is focused through a glass lens on Earth.

The way the light bends indicates the total mass, which includes both visible matter and, potentially, dark matter – so scientists can analyse this, begin to identify where dark matter is located, and understand its properties.

Euclid’s data is revolutionising the study of strong lensing. New techniques using machine learning and AI have been developed to find these rare objects. Citizen science has also contributed significantly, with over 1000 volunteers participating in visual inspections.

This image shows examples of gravitational lenses that Euclid captured in its first observations of the Deep Field areas. Credit: ESA/Euclid/Euclid Consortium/NASA, image processing by M. Walmsley, M. Huertas-Company, J.-C. Cuillandre

UK Science Minister, Lord Vallance said:

The UK space sector is playing a leading role in the Euclid mission which, as this new data shows, is revealing more about the role of gravity in our Universe, and the nature of dark energy and matter. The British-made visible imager and data processing tools are central to these observations.

The technological advances achieved in missions like this will not only benefit our understanding of the universe, but may help us to better process data here on Earth, helping us to grow our economy and support our Plan for Change.

The Euclid mission, launched in July 2023, carries a visible imager (VIS) from the UK, funded by £37 million from the UK Space Agency. The VIS, designed and built by a UCL-led team, is a super high-resolution camera (609 million pixels), with a focal plane about the size of a large pizza box, that can take incredibly detailed pictures of the sky. It is currently observing billions of galaxies up to 10 billion light years away.

The new data release includes observations of distant regions of space, displaying hundreds of thousands of galaxies and many transient phenomena—astronomical events that are temporary or short-lived relative to cosmic history. These include supernovae (explosions of stars at the end of their life cycles), gamma-ray bursts (extremely energetic explosions observed in distant galaxies), and fast radio bursts (brief but intense bursts of radio waves from unknown sources in space).

All of this allows scientists to gain insights into the dynamic processes occurring in the universe. The release classifies over 380,000 galaxies and 500 gravitational lens candidates.

This is a zoom-in of Euclid’s Deep Field North, showing the Cat’s Eye Nebula in the centre of the image, around 3000 light-years away. Also known as NGC 6543, this nebula is a visual ‘fossil record’ of the dynamics and late evolution of a dying star. This dying star is shedding its outer colourful shells. Credit: ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre, E. Bertin, G. Anselmi

ESA’s Director of Science, Prof. Carole Mundell, said:

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.

The ‘quick’ data release

Euclid ‘quick’ releases, such as this one, are of selected areas, intended to demonstrate the data products to be expected in the major data releases that follow, and to allow scientists to sharpen their data analysis tools in preparation. The mission’s first cosmology data will be released to the community in October 2026.

Aprajita Verma, a Senior Researcher at the University of Oxford, said:

This early data release showcases the amazing images that we will receive from the Euclid telescope. Even in this tiny area (less than 0.5% of the Euclid survey), Euclid has revealed millions of galaxies in exquisite detail.

Nestled among these galaxies are strong gravitational lenses. This rare phenomenon is seen around massive galaxies that can distort or warp space-time so much that light from objects behind them can be brought into view as rings, arcs or multiple images.

Verma said:

This is exactly what has been revealed in this early Euclid data, and at a higher frequency than we’ve seen from surveys with ground-based telescopes.

The team used a combination of machine learning with visual inspection from citizen scientists and the team to develop an efficient discovery engine.

Phil Holloway, PhD student at the University of Oxford said:

Incredibly, over 1000 citizen scientists volunteered to hunt for the strong lenses through the Space Warps project on the Zooniverse platform. We are amazed by the interest, dedication and skill of the citizen scientists, we wouldn’t have been able to find 500 of these rare gems without them! This was a huge collaborative effort and this early data signposts that there will be many discoveries to be made with the Euclid Wide Survey - there are exciting times ahead!

Space Warps is a dedicated project to discover strong gravitational lenses co-founded by Phil Marshall, Anupreeta More, and Aprajita Verma on the Zooniverse citizen science platform.

Professor Thomas Collett, from the University of Portsmouth’s Institute of Cosmology and Gravitation, said:

Euclid has provided spectacular image quality across a huge area of the sky, which is critical to discovering small, rare objects. We’ve found 500 new strong gravitational lenses in the Euclid dataset.

These are galaxies distorted into rings of light by the mass of another foreground galaxy. We have combined the strengths of machine learning and citizen scientists to sift out these rare objects from the millions of other galaxies in Euclid. These new lenses will allow us to make new measurements of the mysterious dark matter and dark energy that make up 95% of our Universe but which are poorly understood.

Euclid’s transformative capabilities

Before Euclid, astronomers had to choose between wide-field images from lower resolution telescopes like the Dark Energy Survey in Chile, or detailed zoomed-in images from telescopes like Hubble, but only on small regions. Euclid, with its 609 megapixel camera led by the UK, combines both panoramic mode and detailed imaging. The area mapped in this release is already a significant fraction of all the sky covered by Hubble since 1990.

This innovation is transformative for strong lensing studies, which require large panoramic images to locate rare objects and detailed views to analyse them.

Professor Adam Amara, Chief Scientist at the UK Space Agency, who first proposed the idea for Euclid, said:

Previously, astronomers like me used wide low-resolution surveys to find strong lenses and then requested Hubble for follow-up observations. Now, Euclid accomplishes both tasks in one shot.

This data release is the first clear evidence that Euclid will be a unique rare object finder (as well as an exquisite dark energy measuring machine). In terms of rare objects in the universe, I’m excited to see what ‘unknown-unknowns’ it will discover - it’s been a long wait.

Professor Mark Cropper (Mullard Space Science Laboratory at UCL), who led on designing and developing Euclid’s VIS optical camera over 16 years, working with teams at UCL, Open University and across Europe, said:

Euclid is allowing us to understand the universe on another level entirely. It gives us fine detail over a vast scale. To pick one example, Euclid found 70,000 globular clusters – very old, tightly packed groups of stars – in the Perseus Cluster of galaxies. And it has found 500 strong gravitational lenses, where light from distant galaxies has been bent by intervening matter - that doubles the number we knew about previously. All this and much more in just two days of data.

Dr James Nightingale , Research Fellow, Newcastle University School of Mathematics, Statistics and Physics said:

For the past decade, my research has been defined by painstakingly analysing the same 50 strong gravitational lenses, but with the Q1 data release, I was handed 500 new strong lenses in under a week. It’s a seismic shift — transforming how I do science practically overnight.

UK involvement and contributions

The UK has played a pivotal role in the Euclid mission, contributing significantly to the development of both the mission’s instruments and data processing capabilities.

Marie-Claire Perkinson, Chair of UKSpace Space Science and Exploration Committee said:

The UKSpace Space Science and Exploration committee is delighted to see this data release and the knowledge generated by this exciting mission. We are pleased to see a strong UK contribution – including UKspace member Teledyne who are providing the instrument detectors.

Mullard Space Science Laboratory and XCAM Ltd. have also made significant contributions to the development of the mission, providing leadership of the VIS instrument, and the Charge-Coupled Device test bench (CCD) test bench for the Euclid visible channel.

Daniel Waller, General Manager and Vice-President of Teledyne Space Imaging in Chelmsford Essex said:

Teledyne Space Imaging delivered the detectors for both the VIS and NISP instruments for Euclid. We are humbled by the astonishing detailed results that has been returned so far. The teams here in Chelmsford and in California feel privileged to have made their contribution to this scientific endeavour of understanding our Universe.

In addition to the VIS instrument UK scientists and institutions around the country have developed bespoke data processing tools for Euclid and are analysing the wealth of data being returned by the mission. Five key papers led by UK researchers are shared as part of this data release.

Professor Mike Lockwood, President of the Royal Astronomical Society, said:

To see UK astronomers, space scientists and engineers playing key roles in this extraordinary scientific endeavour is truly inspiring – and what’s even better is that this is just the beginning.

We can look forward to Euclid giving us the most detailed ever 3D map of the cosmos, helping to solve the biggest cosmic mysteries – what the universe is made of, how it evolved, and what its future holds.

The wider benefits of space science

The ripple effects of technological advances in space science extend far beyond the realm of space exploration, driving advances and growth across multiple sectors in the UK. The need for compact and efficient technology in space missions has led to advancements in miniaturisation, which benefit consumer electronics such as smartphones and laptops.

In healthcare, machine learning techniques developed for imaging technologies used in space exploration are being adapted to create more precise medical imaging techniques, potentially improving diagnosis and patient outcomes. The vast amounts of data collected by missions like Euclid are processed using advanced algorithms, which are now being used in healthcare to analyse patient data and predict disease outbreaks.