Admire the rare and beautiful 'astronomical ring' of the universe

A stunning new image sent back from the world's most expensive space telescope, the James Webb Space Telescope, has captured a rare object called an Einstein ring. This object, which at first glance appears to be a beautiful, ghostly ring appearing in the sky, is actually formed by two separate galaxies with extremely strong gravity.

This classic astronomical phenomenon is called gravitational lensing, in which a massive object such as a galaxy or galaxy cluster has enough mass to warp space-time. When a massive object is positioned in front of a more distant object when viewed from Earth, it can act like a magnifying glass, allowing us to see the distant object in much greater detail than we would normally see. This is a fairly common finding in observational astronomy, and is one of the most powerful ways scientists study extremely distant galaxies.

 

Normally, these warped objects appear as curves or distortions due to the force of gravity on space-time. But sometimes, they line up in a way that makes the distant object appear as a near-perfect circle: this is called an Einstein ring. Operations scientist James Webb explains:

When the object is bent and the lensing object aligns precisely, the result is a characteristic Einstein ring shape, appearing as a complete or partial circle of light surrounding the lensing object, depending on the precision of the alignment. Objects like this are ideal laboratories for studying galaxies that are too faint and distant to be observed normally.

The nearest galaxy to us in the centre of this image is an elliptical galaxy (which appears 'smooth' with a bright core) belonging to a galaxy cluster called SMACSJ0028.2-7537, while the more distant galaxy in the background, stretched into a ring shape, is a spiral galaxy (like our own Milky Way). Although this galaxy has been stretched into a ring-like shape, you can still see traces of its spiral arms at the top and bottom of the image.

This image was actually created using data from both James Webb's NIRCam instrument and the Hubble Space Telescope's Wide Field Camera 3, demonstrating the incredible efficiency of these two state-of-the-art telescope systems working together.