WTF?! The James Webb Space Telescope continues to boggle the mind with images of the distant universe that often defy our wildest imaginations. This recent example from the space observatory slots perfectly into that category.
The image in question features a supernova-hosting galaxy captured at three different points in time, all in the same photo. The time-defying feat is the result of gravitational lensing, which occurs when a massive galaxy cluster - in this case, a cluster named RX J2129 that is about 3.2 billion light-years from Earth in the constellation Aquarius - literally warps the fabric of space and time.
The effect gives us three different views of the background galaxy based on the path its light took through / around the lensed object. In the oldest view in which the light took the longest path, we can still see the supernova. In the second and third views, from around 320 days and 1,000 days later, the supernova has already faded out.
The supernova, designated AT 2022riv, is a Type Ia supernova that was first discovered using the Hubble Space Telescope. These supernovae are referred to as "standard candles" because they produce a consistent luminosity at a given distance, thus allowing them to be used as cosmic measuring sticks to help astronomers measure distance in space.
Gravitational lensing can also be used as a magnifying glass to help astronomers peer into the early days of the universe. In one example from 2020, it was used to see a distant galaxy whose light took more than 12 billion years to reach Earth. NASA has also used the technique to uncover half a dozen "dead" galaxies in 2021.
Webb was launched on Christmas Day in 2021 and eventually made its way into orbit around the second Lagrange point nearly a million miles away from Earth. The first full-color images from the telescope were published in July 2022.
The European Space Agency has published the annotated image in multiple formats and resolutions on its website, many of which are suitable for desktop wallpaper use.