When NASA’s Hubble Space Telescope took a snapshot of an elliptical galaxy, it unexpectedly unveiled a luminous red arc of light surrounding it.

This arc is not a camera error or telescope issue — it represents another galaxy, situated an astonishing 19.5 billion light-years from Earth. In contrast, the elliptical galaxy at the heart of the image is significantly closer, at around 2.7 billion light-years away.

The strange, curved shape of the distant galaxy — identified as HerS 020941.1+001557 — is attributable to a cosmic effect known as gravitational lensing. Initially predicted by Albert Einstein in his General Theory of Relativity more than a century ago, gravitational lensing occurs when a colossal object, such as a galaxy, distorts the fabric of space and time, altering the trajectory of light passing through it. In this specific instance, the lensing effect has produced what is called an Einstein ring — a nearly full circle of light formed when a background object aligns exactly with a foreground object and the observer.

The foreground galaxy responsible for this enhancement is SDSS J020941.27+001558.4. Its vast gravitational influence functions like a natural telescope, bending and magnifying the light from the more remote galaxy behind it. This enables astronomers to observe galaxies that would typically be too faint or distant to be seen.

Gravitational lensing may also create optical deceptions, such as numerous or distorted images of the same object — akin to the way a funhouse mirror alters reflections. While contemporary astronomers excel at recognizing these effects, this was not always the case. In 1987, a massive blue arc found near the galaxy cluster Abell 370 was first thought to be one of the largest objects ever uncovered in space. However, later that year, researchers at Stanford University and the National Optical Astronomy Observatory established that it was, in fact, an optical illusion caused by gravitational lensing. The New York Times even published an article titled “Vast Cosmic Object Downgraded to a Mirage,” underscoring the remarkable ramifications of Einstein’s theory.

Einstein rings like the one depicted in this image are formed only when the alignment of the distant galaxy, the lensing galaxy, and Earth is precisely correct. Depending on how accurate this alignment is, the ring may present as a complete circle or a partial arc.

Interestingly, this specific Einstein ring was discovered by a citizen scientist involved in the SPACE WARPS project — a crowdsourced program that encourages volunteers to assist in identifying gravitational lenses in astronomical photographs.

Gravitational lensing has emerged as an essential tool for astronomers, allowing them to examine galaxies that existed billions of years ago. As light requires time to traverse the universe, the image of HerS 020941.1+001557 captures the galaxy as it was approximately 11 billion years ago — long before our sun and Earth came into existence.

And there’s an additional surprise in the image: a third galaxy, SDSS J020941.23+001600.7, seems to photobomb the frame, intersecting part of the red arc and introducing another layer of cosmic intricacy to this extraordinary snapshot.