Scientists have determined that the record-breaking cosmic explosion that lit up the sky with the greatest power we’ve ever seen was caused by a structured jet carrying massive guts of exploded stars headed straight for Earth.

Discovered last October, the gamma-ray burst GRB 221009A was so bright it was difficult for our instruments to measure. But when the first hints of this emerged, scientists rushed to point telescopes in its direction, and thanks to the huge amount of data gathered, an international team of scientists finally figured out how a supernova caused such a powerful explosion.

GRB 221009A, nicknamed BOAT (brightest ever), was the result of the death of a massive star that collapsed into a black hole after removing its outer shell at a relatively close distance of 2.4 billion light-years from us. The gamma-ray burst produced by this collapse contained a narrow, structured jet surrounded by a wider gas stream.

This is unexpected; Our current models predict that only the jet will cause the explosion. These findings have implications for our understanding of how black holes form and how the brightest explosions in the universe occur.

“GRB 221009A represents a major step forward in our understanding of gamma-ray bursts and demonstrates that the most extreme bursts do not fit standard garden physics gamma-ray bursts,” says astronomer Brendan O’Connor of George Washington University. , lead author of the new article.

“GRB 221009A may be the Rosetta Stone equivalent of long gamma-ray bursts, forcing us to reconsider our standard theories of how relativistic outflows occur in massive collapsed stars.”

Gamma-ray bursts are the most powerful explosions in all of space, and they happen in a variety of ways. Long-duration gamma-ray bursts such as GRB 221009A result from the death of massive, rapidly rotating stars.

At the end of their lifetimes, the cores of these stars, no longer supported by the external pressure of fusion, collapse under the influence of gravity, forming a superdense object like a black hole. At the same time, during a big explosion – a supernova – the outer material of the star is ejected outward.

It wasn’t immediately clear what we were looking at with GRB 221009A, but its long duration suggested a supernova. But the power of the blast – up to 18 teraelectron volts, a stunning record – caused a real surprise, and the mystery deepened as scientists continued to dig.

We know that gamma-ray bursts are accompanied by jets, twin columns of material emanating from opposite directions of the collapsing object and carrying material at relative velocities; i.e. a significant percentage of the speed of light. We also know that these jets appear brighter when pointed directly at us; Look directly into the flashlight beam, not at an angle.

Scientists had concluded that GRB 221009A’s jet was aimed at Earth, but the flare that followed the explosion was still bright months later. This is not typical for a narrow emission jet and suggests something else is going on.