Astronomers have reported that a gamma-ray burst, which occurred in our Solar System last autumn, was the most luminous event ever recorded. According to a NASA press release, the gamma-ray burst (GRB) was so intense that it temporarily overwhelmed gamma-ray instruments in space.
This particular GRB, known as “the BOAT” (brightest of all time), was estimated to be 70 times brighter than any previously observed event. But what exactly is a gamma-ray burst?
A GRB marks the 𝐛𝐢𝐫𝐭𝐡 of a black hole and is a truly awe-inspiring phenomenon. When a supermassive star reaches the end of its life and can no longer sustain its mass through core fusion, it collapses under its own gravitational force, resulting in the formation of a black hole.
During this process, two significant events occur. First, the collapse triggers a supernova explosion. Second, the new𝐛𝐨𝐫𝐧 black hole is surrounded by a massive cloud of residual gas and dust, rapidly consuming its surroundings.
The subsequent occurrence, which has been witnessed numerous times but remains a scientific mystery, involves the black hole emitting two powerful jets of high-energy gamma radiation moving in opposite directions at nearly the speed of light.
These cosmic eruptions, lasting only a few seconds, are incredibly bright, leading astronomers to document approximately 12,000 GRBs. Last fall, one of these jets struck our Solar System.
This brightest GRB of all time, named GRB 221009A, was recorded on October 9, 2022. Due to its blinding effect on space instruments, its initial brightness upon reaching our planet was uncertain.
Over the past several months, scientists from various countries, including the United States, China, and Russia, have analyzed data from other instruments to measure and re-measure the burst’s luminosity. The findings revealed that GRB 221009A was 70 times brighter than any previously recorded GRB event.
The amount of gamma radiation emitted by GRB 221009A significantly surpasses that of any other known GRB. Furthermore, researchers have determined that events like this occur only once every 10,000 years.
“GRB 221009A was likely the brightest burst at X-ray and gamma-ray energies to occur since human civilization began,” stated Eric Burns, an assistant professor of physics and astronomy at Louisiana State University, as reported by NASA.
Interestingly, the jets themselves were not the most powerful on record. What made this GRB exceptionally bright was the fact that the jets were narrow and directly aimed at Earth, giving us a full view of the event, much like a deer caught in headlights.
GRBs that are not directly aimed at Earth appear dimmer since we detect less of their radiation.
The researchers recently presented their findings at the American Astronomical Society’s High Energy Astrophysics Division and published the results in The Astrophysical Journal Letters.
However, astronomers are not done investigating. They hope that this GRB could provide insights into the mystery of why black holes emit GRBs in the first place. One existing theory suggests that the jets were powered by a magnetic field amplified by the black hole as it began to spin (yes, black holes can spin).
Additional observations using the James Webb Space Telescope and Hubble Space Telescope are planned for the coming months.