Webb images an outstanding Einstein ring

The James Webb Space Telescope imaged an unusual galaxy that appears to be sporting the spiral arms of a more distant galaxy. On March 27, 2025, ESA shared this image of an Einstein ring, a rare event when one galaxy is perfectly positioned in front of a more distant galaxy. The massive foreground galaxy acts as a gravitational lens, bending the light of the more distant galaxy. In this case, we see an elliptical galaxy at center with the spiral galaxy wrapped around it in an Einstein ring.

As ESA explained, Einstein rings are possible because:

spacetime, the fabric of the universe itself, is bent by mass, and therefore light traveling through space and time is bent as well. This effect is much too subtle to be observed on a local level, but it sometimes becomes clearly observable when dealing with curvatures of light on enormous, astronomical scales, such as when the light from one galaxy is bent around another galaxy or galaxy cluster. When the lensed object and the lensing object line up just so, the result is the distinctive Einstein ring shape, which appears as a full circle (as seen here) or a partial circle of light around the lensing object, depending on the precision of the alignment.

The galaxies in the image

The galaxy at the center is the one that is closest to us. This is an elliptical galaxy with a bright core and fuzzy, diffuse body. Astronomers dubbed it SMACSJ0028.2-7537.

Meanwhile, the rings are part of a more distant spiral galaxy. The light from this galaxy gets warped as it passes the massive foreground galaxy. Even so, this unique Einstein ring still allows us to make out star cluster and gas lanes.

Bottom line: The Webb space telescope captured this unusual image of two galaxies. The closer, elliptical galaxy acts as a gravitational lens, warping the light from a spiral galaxy behind it and allowing us to see it in the form of an Einstein ring.

Via ESA

Read more: Einstein ring spotted around a nearby galaxy