According to astronomers, the distant supernova of "Requiem" will be seen again in 2037.

Astronomers predict that a distant supernova previously photographed by the Hubble Space Telescope will be visible to the Earth again in 2037.

The supernova, called Requiem, is the result of a stellar explosion at approximately 10 billion light-years. It was seen three times at the legendary space observatory in 2016, thanks to a phenomenon known as a gravitational lens.

The gravitational lens occurs near super-massive celestial bodies that can fold and divide light, magnifying and distorting images of objects behind them. In supernova Requiem, a giant galaxy cluster called MACS J0138.0-2155 served as the magnifying glass. It revealed the stellar explosion in three different snapshots based on three different paths the supernova's light took through the cluster.

The prediction that the supernova will be visible again (although not to the naked eye) is based on computer modeling the distribution of matter inside the cluster, which lies some 4 billion light-years away from Earth.

This final display of the supernova will be delayed by more than two decades compared to the previous three sightings because the light carrying the last image must travel through the central part of the cluster, which is also the densest due to the concentration of dark matter, a team of European and American researchers said in a statement.

"This is the last one to arrive because it's like a train that has to go deep down into a valley and climb back out again," Steve Rodney, an astronomer at the University of South Carolina and lead scientist on the new research predicting Requiem's return, said in the statement. "This is the slowest journey to the light."

The previous three observations were accidentally discovered in 2019 in Hubble's archived data three years after acquiring the images by the observatory.

An astronomer at the University of Copenhagen in Denmark, Gabe Brammer, stumbled on the supernova by accident while looking for unknown distant galaxies as part of an ongoing research program called REsolved QUIEscent Magnified Galaxies (REQUIEM), hence the supernova's name.

Initially, he only spotted a tiny dot in the 2016 images and thought it was a galaxy hidden far behind the massive cluster and visible through the gravity lens.

"On further inspection of the 2016 data, I noticed there were three magnified objects, two red and a purple," Brammer, who is a co-author of the new research, said in the statement.

The three minor points of different brightness levels were dispersed in an arc around the cluster nucleus. Brammer went on to research the objects in new images. But to his astonishment, they were gone.

"Immediately, it suggested to me that it was not a distant galaxy but a transient source in this system that had faded from view in the 2019 images like a light bulb that had been flicked off."

A supernova explosion lasts no more than ten seconds. After that, the luminous flash it creates fades away quickly and disappears entirely in a year.

By taking a closer look at the images, the scientists also saw that the light points were surrounded by dusty swabs, probably amplified the supernova host galaxy snapshots.

Rodney, Brammer, and astronomer Johan Richard from the University of Lyon, France, deepen their event analysis. These three observations produced maps of the distribution of dark matter in the cluster to understand how its gravity bends and distorts the light. In addition to the 2037 observation, they calculated that the supernova may be visible again by 2042 but that the final event is likely too low to produce valuable observations.

The astronomers hope that this new possibility of observation will help them collect more information about the distant cluster and the mysterious dark matter distribution. Dark matter, believed in making up the majority of all value in the universe, is responsible for most of the gravitational forces in the universe and therefore plays an essential role in its expansion.

"The discovery [of the supernova Requiem] is the third example of a multi-frame supernova for which we can measure the delay in arrival times," said Rodney. "That's the furthest of the three, and the timeline is extraordinarily long."

Tracking lens supernovae has become easier over the past 20 years and will become even easier as increasingly powerful wide-field telescopes like Vera C are activated. Rubin Observatory in Chile or the NASA Nancy Grace Roman Space Telescope.