We all know the trope about the dying character who leaves behind one last clue as to whom their murderer was. (Looking at you, The Da Vinci Code.) Gigantic celestial bodies, it turns out, can do the same thing right before they “die” away too. Like one very distant exploding star did when it sent out a brief yet powerful gamma-ray burst (GRB) just before it went boom 6.6 billion years ago. Its “murderer”? Itself, of course.
Newsweek reported on the GRB, which NASA’s Fermi Gamma-ray Space Telescope detected on August 26 of last year. NASA says the GRB had been racing toward Earth for “nearly half the present age” of the universe as the star that loosed it in the direction of our home planet is billions of light-years away.
While it’s common to detect GRBs—the strongest and brightest explosions in the universe—this one, dubbed GRB 200826A, was unique for several reasons. Namely, it was the shortest GRB caused by the “death” of a massive star that astronomers had ever observed.
The entire burst lasted only approximately a second, which is short even for GRBs. The bursts of high-energy radiation last, on average, for about 30 seconds, according to NASA. While there are shorter-length ones, this GRB was unique. Rather than merging two black holes, which astronomers would’ve expected, it linked to an exploding star.
As for the event sequence leading up to astronomers detecting GRB 200826A, NASA offers a visualization in the explainer above. In the clip, the space agency shows how a black hole inside the collapsing star responsible for the GRB formed thanks to hyper-intense gravity and then subsequently shot out jets of high-energy particles; high-energy particles that pierced the collapsing star for just a second. (Below is a real image of the GRB’s “afterglow,” which was in the visual part of the electromagnetic spectrum.)
“We already knew some GRBs from massive stars could register as short GRBs, but we thought this was due to instrumental limitations,” Bin-bin Zhang at Nanjing University in China and the University of Nevada, Las Vegas, said in a NASA press release. “Now we know dying stars can produce short bursts, too.”
Featured image: NASA