The Hubble Space Telescope has captured an image of GAL-CLUS-022058s, the largest and one of the most complete Einstein rings ever discovered. This type of structure’s name comes from the fact that it was theorized by Albert Einstein in his theory of general relativity. It’s in fact the result of a gravitational lensing effect, which distorts the image of an object behind a galaxy or a galaxy cluster. In this case, the ring’s “liquid” look and the fact that it was identified in the constellation of Fornax, the Furnace, led to the nickname of “Molten Ring”.

Galaxies and even more galaxy clusters that distort the light passing near them with their powerful gravity are gravitational lenses because they magnify the image of the objects between them and the Earth. The problem is that the image arriving on Earth is typically distorted in various ways, depending on the shape of the lens and the distance and position of the object behind it. Sometimes, the result is quite smooth, resulting in a ring shape. The name Einstein ring is due precisely to the fact that it’s a result predicted by the theory of general relativity.

In the case of GAL-CLUS-022058s, a galaxy is almost exactly aligned with a galaxy cluster about 4 billion light years away and with the Earth. The result is that its image was distorted in a regular way by the galaxy in the center of the cluster forming the almost complete image of a ring. The other galaxies in the cluster generate further distortions which are irregular. The consequence is that the ring is incomplete and its shape is imperfect.

The distortions generated by gravitational lenses require sophisticated processing to reconstruct the original image. Despite this, the magnifications they offer are an advantage astronomers appreciate to observe galaxies billions of light-years away in detail otherwise impossible to catch.

The Einstein ring made up of GAL-CLUS-022058s has a distortion that gives it a liquid appearance. The optical and infrared filters used by the Hubble Space Telescope’s Wide Field Camera 3 (WFC3) emphasize the appearance of a ring of molten gold. This object was identified in the constellation of Fornax, which means the Furnace, and the result was the nickname Molten Ring. It’s an effect that is both spectacular and useful for astronomers to study this object.