A remarkable cosmic event has been identified, marking the longest and most unusual gamma-ray burst ever recorded. Dubbed GRB 250702B, this extraordinary explosion was detected on July 2, 2023, and persisted for several days, defying established expectations about such phenomena. Typically, gamma-ray bursts, known as the universe’s most powerful explosions, last only seconds or minutes. They are generally triggered by the collapse of massive stars or the collision of neutron stars.
Multiple satellites, including NASA’s Fermi and Swift telescopes, collaborated to capture this unprecedented event. No single observatory was able to track the entire outburst, so scientists combined data from various sources to piece together a comprehensive view of the explosion. Researchers believe that this record-breaking event could unveil a new mechanism by which black holes destroy stars, a process not explained by existing theories.
“This is certainly an outburst unlike any other we’ve seen in the past 50 years,” stated Eliza Neights, a researcher at NASA affiliated with George Washington University. Follow-up observations traced the explosion to a galaxy approximately 8 billion light-years away, indicating that it occurred long before Earth came into existence.
Details of the Discovery
Images captured by the James Webb Space Telescope and other instruments revealed the radiation from the explosion penetrating through dense bands of dust in the galaxy. Andrew Levan, an astrophysics professor at Radboud University in the Netherlands, who led part of the research, noted that the galaxy appears to be either two merging galaxies or a single massive one obscured by a dark band of dust.
The energy released during this event was staggering, equivalent to the luminosity of 1,000 suns shining for 10 billion years, all produced within a matter of days. The initial burst lasted over seven hours, more than double the duration of any previous gamma-ray burst. “The resolution of Webb is unbelievable,” remarked Huei Sears, a researcher from Rutgers University who contributed to the observations. “We can see so clearly that the burst shined through this dust lane spilling across the galaxy.”
Preliminary findings regarding the gamma-ray burst will be published in the Monthly Notices of the Royal Astronomical Society, while additional results are set to appear in The Astrophysical Journal Letters.
Possible Explanations for the Phenomenon
Most scientists agree that the prolonged emission likely resulted from a black hole consuming a star. However, two alternative scenarios remain under consideration. One theory suggests that a medium-sized black hole, thousands of times the mass of the sun, disrupted a wandering star, ripping it apart before ultimately absorbing it.
The second hypothesis involves a smaller black hole orbiting a companion star. Over time, this black hole would siphon gas from its partner, eventually plunging into the star and consuming it rapidly. In both cases, the gas stripped from the star would spiral into a superheated disk around the black hole, creating narrow jets of energy that move at nearly the speed of light, responsible for the gamma-ray emissions detected from Earth.
This event also defied other established norms. X-rays were detected a full day before the primary explosion and continued to flare for two days afterwards, a behavior not previously observed in typical gamma-ray bursts. Additionally, there was no evidence of a supernova, the bright explosion that usually follows the collapse of a star. These unusual characteristics suggest that scientists may be observing a new type of cosmic event.
To further understand this extraordinary phenomenon, additional observations will be crucial, as researchers seek to unravel the mysteries surrounding this unprecedented gamma-ray burst.
