Most Distant Cosmic Explosion Ever May Have Been Photobombing Russian Space Junk

A bright flash of light, believed to be from the most distant cosmic explosion ever spotted by astronomers, may have a more down-to-earth explanation—light reflected from space junk.

According to research published in 2020 and authored by Kavli Institute for Astronomy and Astrophysics and Peking University researcher Linhua Jiang and his team, the gamma-ray burst (GRB) was traced back to GN-z11 32. This is a galaxy so distant that the Hubble Space Telescope sees it as it was 13.2 billion years ago, just 400 million years after the Big Bang.

Two new research papers published in the journal Nature Astronomy suggest that the flash of light was actually more of a flash in the pan. The authors of one new paper—including Adam Mickiewicz University, Astronomical Observatory, and Faculty of Physics researcher, Michał Jerzy Michałowski—suggest that the burst of light was actually light reflected from a spent Russian rocket that "photobombed" the astronomers as they were collecting data.

"We show a clear association of GN-z11-flash with the Breeze-M upper stage of
a Russian Proton rocket in a highly elliptical orbit," the authors said in the paper. "This rules out GN-z11-flash as the most distant GRB ever detected. This also
highlights the importance of a complete database of Earth satellites and debris, which would allow proper interpretation of astronomical observations."

The reason astronomers have investigated this GRB so closely is due to the fact that even though these energetic bursts of light are associated with the complete gravitational collapse of a dead star into a black hole—something that happens fairly frequently—the chances of actually having a telescope trained on a region of space as this happens are slim at best.

The chances of catching such a GRB from a galaxy that existed when the Universe was just 400 million years old in data collected by the W. M. Keck Observatory in Hawaii are one in 10 billion.

To determine if this flash of light was from a lighter reflected by a piece of human-made space debris, Michałowski, and his team searched Space-Track, the largest publicly available database of Earth satellites and space debris, and found that Breeze-M space debris had a trajectory that brought it in line with the distant galaxy GN-z11 as the flash was recorded.

Russian Proton Rocket launch
A stock image of a successful Russian Proton launch in 2012. That same year a similar rock exploded and left debris orbiting around Earth. New research suggests this debris could have led to a flash of light that was mistaken for a GRB. STR / Stringer/Getty

The debris of Breeze-M was left in orbit when the Russian rocket exploded on October 16, 2012. Following the explosion, NASA identified 700 fragments of the rocket left behind, concerned they present a risk to satellites and future launches.

The wreckage of this Russian rocket is just one of many pieces of metal from man-made equipment left in space, that includes everything from rocket boosters to screwdrivers dropped on spacewalks.

These pieces of metal cause up to 10,000 flashes of light per hour in the night sky according to the Weizmann Institute of Science astrophysics professor Eran Ofek.

In separate research also published in Nature Communications Niels Bohr Institute associate professor, Charles Steinhardt points out that the chances of a telescope picking up a flash of light from orbiting metal debris are still between one in 1,000 and one in 10,000. This is still far more likely than the one in 10 billion probability of catching a GRB from GN-z11-flash.

"The extreme improbability of the transient source being a GRB in the very early Universe requires robust elimination of all plausible alternative hypotheses," say Steinhardt and his co-authors. "Solar System objects—natural or artificial—are a far more probable explanation for these phenomena."

Linhua Jiang, one of the researchers who first identified the burst of light and associated it with a GRB from GN-z11, and his colleagues aren't quite ready to give up on their findings, just yet, however.

They have already responded to the two papers that question the nature of their 2020 findings. The team writes: "While one cannot completely rule out the possibility of unknown satellites (or debris), we find that either the chance probabilities of being a satellite estimated by these authors have been largely overestimated or their identified satellites were ruled out in our original analysis."

Linhua Jiang and his co-authors added that they have conducted new calculations which they say show that the probability of the flash being from a satellite is still lower than the chance of it being a GRB originating from GN-z11.

They also say they have confirmed, by using CalSky, a website that could be used to track objects in the sky but is no longer operational, that the Breeze-M debris had moved clear of the Keck telescope and this couldn't account for the flash.

Institute of Astrophysics of Andalusia astronomer Christina Thöne was not involved with any of the research above. She told Science that she is also cautious of the results obtained by Linhua Jiang and his team.

She added, however, how important their result could be if it were to be proven correct because the presence of a GRB so early in the Universe's history would reveal a great deal about the massive stars that were dying then and how they dispersed heavy elements throughout the infant Universe.

She concluded: "If it were real, that would be amazing."

GNz11
An image of the galaxy GN-z11, the most distant galaxy ever observed. Astronomers are currently engaged in a debate over whether a flash of light detected last year was a cosmic explosion in this galaxy or something much more mundane. Hubble/NASA