Stunning image shows the closest ever Einstein ring
Albert Einstein himself thought that the eponymous Einstein ring would be impossible to observe, but the Euclid telescope has picked one up just 600 million light years from Earth
By Alex Wilkins
10 February 2025
The closest ever Einstein ring, picked up by the European Space Agency’s Euclid space telescope
ESA
Astronomers have identified the closest ever Einstein ring, a rare phenomenon where light from a further-off galaxy is bent by the gravity of a galaxy closer to Earth. The ring was previously thought to be one galaxy and was identified more than 100 years ago.
Galactic lenses like this one, which is the closest astronomers have ever found, were predicted by Albert Einstein in 1936 from his theory of general relativity. At the time, he thought such an effect would be impossible to observe. In fact, he would have been able to see one if he had just had a powerful enough telescope. “It was there all along, but we had no idea,” says Thomas Collett at the University of Portsmouth, UK.
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Collett and his team realised that the oval-shaped galaxy NGC 6505, which is about 600 million light years from Earth and was first spotted in 1884, was actually bending the light of a second galaxy behind it, about 6 billion light years from Earth.
A close-up of the Einstein ring ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre, T. Li
Team member Bruno Altieri at the European Space Agency observed the Einstein ring while he was validating early testing data from the Euclid telescope, which has recently started scanning billions of galaxies over an area that will eventually span a third of the night sky. “There was this abundantly obvious Einstein ring. There’s not that many things in the universe that can produce a ring like this,” says Collett.
