What is an Einstein ring? NASA captures stunning galactic merger illusion

Tengrinews.kz - NASA has shared a breathtaking image on Instagram that appears to show two galaxies merging into one. However, the reality is even more fascinating.

The image showcases an Einstein ring, a rare optical phenomenon caused by gravitational lensing. At first glance, it looks like a single, unusually shaped galaxy, but in fact, it is two separate galaxies located at vastly different distances. The gravity of the nearer galaxy bends the light from the distant one, creating the illusion of a ring.

How an Einstein ring forms

As light from a distant galaxy travels through space, it passes near a massive foreground galaxy, which warps space-time due to its immense gravity. This bending effect, known as gravitational lensing, distorts the background galaxy’s light, curving it around the foreground galaxy like a cosmic magnifying glass.

For an Einstein ring to appear, the galaxies must be perfectly aligned along our line of sight. When this happens, the distant galaxy's light is bent symmetrically, forming the characteristic circular shape.

What the image reveals

At the center of the image is a massive elliptical galaxy, glowing as a bright, oval-shaped core. Surrounding it is a striking, curved band of light—an amplified and distorted view of a distant spiral galaxy. Its spiral arms appear stretched into an arc, forming a glowing blue ring against the dark backdrop of space, with several other distant galaxies visible in the background.

Previously, NASA's Chandra X-ray Observatory captured an incredibly colorful scene of two spiral galaxies merging, 250 million light years away.