For most of us, the amazing images of space released by observatories like the Hubble Space Telescope and James Webb Space Telescope are just that: amazing images.
But for scientists, they offer an unprecedented glimpse into the workings of the Universe, enabling them to see planets forming, stars dying and galaxies colliding.
More space images
This James Webb Space Telescope shows something even more mind-blowing than any of those things, and it's a quirk of spacetime that was predicted by Albert Einstein.
It shows an 'Einstein ring', and the physics behind it sounds more science fiction than science fact.
Let's delve into seven reasons why this image is so amazing.
It's a trick-of-light illusion named after Einstein
What looks like a perfectly symmetrical glowing circle is not one galaxy, but two: one distant galaxy and one much closer galaxy.
The closer galaxy in the centre is acting like a natural lens, warping the light from the more distant galaxy directly behind it.
Yes, the mass of the foreground galaxy is actually warping and bending light from the distant galaxy.
This bending of light around a massive object is called gravitational lensing, and when things align just right, the result is an almost perfect circle.
The phenomenon known as an Einstein ring, after Albert Einstein, who predicted it with his theory of general relativity.
You’re seeing the curvature of spacetime
The ring exists because massive objects like galaxies actually bend spacetime.
Light doesn't travel in straight lines through the Universe; it follows the curves of this warped cosmic fabric.
Most of the time, the effect is too subtle to be noticed, but when a massive galaxy sits directly in front of a more distant one, it bends the light from the background galaxy around it.
The light appears as if it’s wrapping itself around the foreground galaxy. You're looking at light that has been curved by gravity itself.
It’s a rare alignment
To get a full Einstein ring like this, the galaxies have to be aligned almost perfectly.
Partial rings and arcs are more common, but this nearly complete circle is something special.
It's like one galaxy photobombing another, and getting the alignment just right.
It reveals a galaxy we shouldn’t be able to see
The galaxy forming the ring is farther away and much fainter than astronomers could normally see in any detail.
But thanks to gravitational lensing, its light is magnified and distorted into view.
That makes Einstein rings like this a sort of cosmic magnifying glass, letting astronomers study features in galaxies that would otherwise be invisible.
You can still spot the galaxy's arms and star clusters
Even though the background galaxy’s light has been warped into a ring, Webb’s sharp vision reveals surprisingly detailed structures.
Look close and you can see spiral arms, glowing clouds of gas and bright star clusters.
It involves two different types of galaxy
At the heart of the ring sits a massive elliptical galaxy, smooth and bright, belonging to a galaxy cluster known as SMACSJ0028.2-7537.
The ring of light is from a more distant spiral galaxy, whose graceful arms seem as though stretched into a loop by gravity.
This is cutting-edge investigative cosmology
This image comes from the Strong Lensing and Cluster Evolution (SLICE) survey, led by astronomer Guillaume Mahler and an international team.
They’re using JWST to trace the evolution of galaxy clusters across 8 billion years of cosmic history, targeting over 180 clusters.
The data also includes contributions from the Hubble Space Telescope.
