Cosmic illusion captured by Euclid telescope

The ring of light surrounding the centre of the galaxy NGC 6505, captured by ESA’s Euclid telescope, is a stunning example of an Einstein ring, an extremely rare phenomenon. When we observe a distant galaxy, its light may pass by a closer galaxy. The gravity of this foreground galaxy bends and magnifies the travelling light coming from the background galaxy, acting like a natural lens, creating a bright circle. This phenomenon was first predicted by Albert Einstein, hence the name 'Einstein ring'. 

These Einstein rings are a rich laboratory for scientists. Studying their gravitational effects can help us learn about the expansion of the Universe and detect the effects of invisible dark matter and dark energy – questions at the heart of ESA's Euclid mission.