What is significant about the newly discovered Einstein Ring and how does it help test Einstein's theory of general relativity?

The newly discovered Einstein Ring around galaxy NGC 6505 is exceptionally bright compared to other known Einstein Rings and provides a unique opportunity to test Einstein's theory of general relativity. Researchers can measure the lensing galaxy's mass in two ways: by analyzing how light bends and by observing the velocity of its stars. Einstein's theory predicts these values should be identical. When calculations were performed, researchers found the mass to be slightly higher than expected based on the estimated number of stars, which could indicate the presence of dark matter. The ring's proximity to Earth and Euclid telescope's imaging capabilities make it easier to distinguish the four images of the distant galaxy, making this a valuable discovery for testing gravitational models.