The mystery behind the brightest explosion ever seen has finally been solved.
In October of last year, Earth was hit by a burst that became known as the Brightest of All Time, or BOAT. It was recorded by telescopes around the world, and scientists have been struggling to explain it ever since.
The explosion was a burst of gamma rays, the most violent and energetic explosions anywhere in the universe. In just a few seconds, they can produce as much energy as the Sun will produce in its entire lifetime.
The gamma-ray burst, officially known as GRB 221009A but better known as BOAT, is thought to have erupted when a massive star collapsed into a black hole. But scientists weren’t sure why exactly this example shone so brightly in space.
Now researchers believe they can understand why this gamma-ray burst was so powerful. It was aimed directly at Earth and pulled up a large amount of stellar material.
This is stated in a new article published in the journal Scientific progress. Although scientists previously assumed that the burst’s brightness was a result of its angle, something of a mystery remains: the ends of the jet cannot be seen.
“The slow fading of the afterglow is not characteristic of a narrow jet of gas, and knowing this led us to suspect that there was an additional reason for the intensity of the explosion, and our mathematical models confirmed this,” said Hendrik Van Eerten of the University of Bath.
“Our work clearly shows that a GRB has a unique structure, with observations gradually revealing a narrow jet embedded in a broader gas stream where an isolated jet would normally be expected.”
The discovery that the burst has different jets than those typically found in such powerful events helps explain the unusual behavior, but also shows that GRBs don’t always behave as expected.
“GRB 221009A represents a huge step forward in our understanding of gamma rays and demonstrates that the most extreme bursts do not obey the standard physics accepted for garden-variety gamma rays,” said Brendan O’Connor, a GW graduate student and the lead study author said.
“GRB 221009A may be the Rosetta Stone equivalent of long GRBs, forcing us to reconsider our standard theories of how relativistic outflows form in collapsing massive stars.”
The work is described in a new paper, “Structured Jet Explains Extreme GRB 221009,” published in the journal Scientific progress.