Record-Breaking Gamma-Ray Burst Leaves Astrophysicists in Awe

On Oct. 9, an unbelievably powerful influx of X-rays and gamma rays infiltrated our solar system. It was likely the result of a massive explosion that happened 2.4 billion light-years away from Earth -- and it's left the science community stunned.

In the wake of the explosion, astrophysicists worldwide turned their telescopes toward the spectacular show, watching it unfold from a variety of cosmic vantage points. And as they vigilantly studied the event's glimmering afterglow over the following week, they grew shocked by how utterly bright this gamma-ray burst seems to have been. 

Eventually, the spectacle's sheer intensity earned it a fitting (very millennial) name to accompany its robotic title of GRB221009A: B.O.A.T. -- the "brightest of all time."

"This GRB is an extraordinarily rare event," Jillian Rastinejad, an astronomer at Northwestern University, said in a statement. "It was so bright that it triggered the Swift gamma-ray telescopes twice and fully saturated the detectors -- something I haven't seen in my time observing GRBs."

So, what could be the root of this record-breaking eruption? Well, scientists reasoned, perhaps something just as mind-bendingly extreme. 

As of now, the leading hypothesis is this GRB was generated by the death of an ancient star as it transformed into a monstrous black hole. 

The idea here is that a huge supernova in the distant universe might have spurred the birth of a black hole, and as black holes are known to spew supreme particle-jets traveling at nearly the speed of light, maybe this one's jet spit its contents toward Earth. 

Perhaps Oct. 9 was the day we received evidence of the budding abyss.

A 'once-in-a-century' opportunity

"We think this is a once-in-a-century opportunity to address some of the most fundamental questions regarding these explosions, from the formation of black holes to tests of dark matter models," Brendan O'Connor, an astrophysicist at the University of Maryland who helped initially observe the GRB, said in a statement.

Plus, if the burst really is connected to the genesis of an abyss like scientists imagine, it could provide us with valuable insight about how matter behaves while traveling near the speed of light, how stars collapse into unimaginably dense voids, and in a broader sense, what the conditions might be like in a galaxy other than our own -- the distant realm where B.O.A.T. was born.

However, it's worth mentioning that everyone involved with researching this GRB is being super careful before making a final declaration of cause. Teams are still observing the event's "afterglow," in order to pinpoint whether the dead star; black hole theory stands strong. 

"Given that most other long GRBs result from a massive star collapsing, we have every reason to believe that we will find direct evidence of a supernova," Rastinejad said. "But that will take more work and time to confirm, and the universe could always surprise us."

GRBs can also be associated with other cosmic marvels. As an example, shorter ones, which last mere fractions of a second, tend to stem from neutron star collisions -- the crash of stellar bodies so dense a tablespoon of one is equal to something like the weight of Mount Everest.

On the bright side, though, because this GRB is so bright and in its infancy, scientists expect to be able to monitor it for several months. After one month, Rastinejad expects evidence of the event to disappear behind the sun, but once it comes back out early next year, says "we will be excited to see the GRB as a messy 'toddler.' Then, we will be ready and waiting to capture it on camera."

All eyes are on B.O.A.T.

"The record-breaking nature of this GRB has reinvigorated the larger observational community in a big way," Rasinejad said. "Everyone -- even those who don't typically study GRBs -- has tried to point their detectors at it. It is a beautiful and surreal thing to be a part of and to watch how this story unfolds."

On one hand, NASA instruments on the International Space Station like the NICER X-Ray Telescope and a Japanese detector dubbed the Orbiting High-energy Monitor Alert Network are involved. Then you have two independent teams, one led by Rastinejad and the other by O'Connor, utilizing the ground-based Gemini South telescope in Chile. And that just scratches the surface of who's staring at the electrifying burst.

With all eyes on B.O.A.T, even if it turns out to be true that this ultra-bright GRB is the product of a star's collapse, there'd remain far more to learn from it. We'd have the "how," but some researchers are especially interested in understanding why the collapse would have spurred an event with this level of energy.

Although explosive GRB eruptions are captured a couple times per week, Wen-fai Fong, an astrophysicist at Northwestern University, emphasizes that "as long as we have been able to detect GRBs, there is no question that this GRB is the brightest that we have ever witnessed by a factor of 10 or more."

It's also curious that such high-energy rays could survive a 2.4 billion year-long journey to our planet in the first place. As the National Science Foundation's NOIRLab puts it, scientists are wondering how particles emitted by the burst could "defy our standard understanding of physics."

To get to the bottom of all this, it's promising that scientists believe this burst is much closer to Earth than your average GRB. This means we can glean lots of details from it that otherwise might be too faint to see. 

And even though such proximity may also partially explain why it appears so luminescent to us, "it's also among the most energetic and luminous bursts ever seen regardless of distance, making it doubly exciting," Roberta Pillera, the astrophysicist at the Polytechnic University of Bari, Italy, who led initial communications about the burst, said in a statement.

As NASA simply summarized, "another GRB this bright may not appear for decades."