Europe’s New Space Telescope Finds Perfect ‘Ring of Light’ Predicted by Einstein

A spectacular ring of light, predicted by Einstein’s theory of relativity but never before seen in this galaxy, has been discovered by Europe’s new Euclid space telescope just months into its mission. The finding, which occurred during routine testing of the spacecraft, reveals the extraordinary capabilities of this new observatory and hints at the thousands of cosmic discoveries that may lie ahead.

The ring appears around NGC 6505, a galaxy just 590 million light-years from Earth – practically next door in cosmic terms. What makes this discovery particularly remarkable is that while the galaxy has been known to astronomers since 1884, this striking feature remained undetected until now.

“I look at the data from Euclid as it comes in,” said Bruno Altieri, Euclid Archive Scientist, who first spotted the phenomenon in September 2023. “Even from that first observation, I could see it, but after Euclid made more observations of the area, we could see a perfect Einstein ring. For me, with a lifelong interest in gravitational lensing, that was amazing.”

The luminous ring is created by an optical illusion on a cosmic scale. Light from a distant galaxy, located 4.42 billion light-years away, is bent and focused by the immense gravitational field of NGC 6505, which acts like a giant magnifying glass in space. When such distant objects align perfectly, the light forms a complete circle – an Einstein ring.

“An Einstein ring is an example of strong gravitational lensing,” explained Conor O’Riordan of the Max Planck Institute for Astrophysics, lead author of the first scientific paper analyzing the ring. “All strong lenses are special, because they’re so rare, and they’re incredibly useful scientifically. This one is particularly special, because it’s so close to Earth and the alignment makes it very beautiful.”

The discovery demonstrates the exceptional capabilities of Euclid, which launched on July 1, 2023, on a mission to map dark matter and investigate dark energy across the universe. “I find it very intriguing that this ring was observed within a well-known galaxy,” said Valeria Pettorino, ESA Euclid Project Scientist. “This demonstrates how powerful Euclid is, finding new things even in places we thought we knew well.”

Until now, astronomers had identified fewer than 1,000 strong gravitational lenses across the entire sky. Euclid is expected to find around 100,000 during its six-year mission as it maps more than a third of the heavens. To discover such a spectacular example so early in the mission – and so close to Earth – is extraordinary.

“Euclid is going to revolutionize the field, with all this data we’ve never had before,” O’Riordan added.

Beyond their visual appeal, Einstein rings serve as natural cosmic laboratories. By studying how gravity bends light in these systems, scientists can investigate dark matter’s distribution, measure the universe’s expansion rate, and peer deeper into space than would otherwise be possible.

The telescope began its systematic survey of the sky on February 14, 2024, gradually building what will become the most extensive three-dimensional map of the universe ever created. This early discovery suggests Euclid is well-positioned to unlock many more cosmic secrets in the years ahead.