The ESA’s Euclid mission has made a very rare and stunning discovery by clearly imaging an Einstein ring phenomenon. It was discovered more or less by chance while the telescope was still in the early stages of calibration and testing. The first batch of data returned from the spacecraft was reviewed by Bruno Altieri, Euclid archive scientist.
Launched in July 2023, Euclid’s main mission is dedicated to unlocking the secrets of the dark universe by studying dark energy and dark matter, which are enigmatic cosmic forces that affect the universe but remain hidden. The highly sensitive instruments on board the telescope have been developed specifically to map these elusive forces across long stretches of space. Yet it was during the early calibration phase when this astounding instance of an Einstein ring was recorded.
Einstein rings arise when light from a faraway galaxy is distorted and amplified by a foreground object, causing a glowing ring effect. The phenomenon was named after the physicist Albert Einstein. His general theory of relativity conceived light changing course along what tilted geometries outside big objects’ gravitational pull. The rings are rare, but they provide an exceptional opportunity to see the underlying structure of the universe.
In this instance, Euclid captured the galaxy NGC 6505, which is about 590 million light-years away from Earth, next to a ring of glimmering light. This ring of light did not belong to NGC 6505 but to a more distant galaxy, about 4.42 billion light-years away. What was exciting was that this other galaxy was never observed before, which adds an exciting new dimension to this discovery.
The team’s findings made it into the journal Astronomy & Astrophysics, where they elaborated on how the discovery can bolster knowledge of cosmic phenomena including dark energy. “This discovery shows how powerful Euclid is,” says Valeria Pettorino, ESA Euclid project scientist.
