Astronomers have recently made a groundbreaking discovery: the longest gamma-ray burst (GRB) ever recorded. This cosmic explosion, named GRB 250702B, lasted an incredible seven hours. Scientists suspect it might be caused by a black hole devouring a star.
Gamma-ray bursts are among the most energetic events we know of, rivaling the energy from the Big Bang. When NASA’s Fermi Gamma-ray Space Telescope first detected GRB 250702B on July 2, 2025, it stood out from over 15,000 GRBs observed so far. It wasn’t just the duration that was remarkable; this burst sent out multiple explosive waves over several days, offering a rare chance for study.
Eliza Neights, a researcher at George Washington University and NASA’s Goddard Space Flight Center, noted that this explosion is unique. “This is certainly an outburst unlike any other we’ve seen in the past 50 years,” she stated. The initial gamma-ray wave lasted nearly twice as long as the previous record-holder.
After the initial detection, astronomers followed up using the Very Large Telescope in Chile. This confirmed the origin of the GRB, which exploded in a distant galaxy billions of light-years from Earth.
Jonathan Carney, a researcher from the University of North Carolina at Chapel Hill, led a team that studied the explosion’s aftermath with some of the world’s top telescopes. He explained that being able to quickly point the telescopes at such transient events is crucial for understanding the night sky’s many mysteries.
So what caused this astonishing GRB? Scientists believe the gamma-ray signal emerged from a fast-moving jet of plasma smashing into surrounding gas and dust. The host galaxy of GRB 250702B is heavier than those of other GRBs, possibly indicating more intense cosmic activity.
Current theories offer three potential scenarios for the explosion. One theory suggests that a black hole collided with a star stripped of its outer layers. Another possibility involves smaller celestial bodies, like a planet, getting pulled apart by a black hole’s gravity. The third scenario points to a rare type of black hole, called an intermediate-mass black hole, which is believed to exist in large numbers but is difficult to detect. If GRB 250702B resulted from this class of black hole, it would mark a significant milestone in astrophysics.
Studying GRB 250702B helps scientists piece together the complex events that occur in the universe. As Carney said, “The uncovering of these cosmic mysteries demonstrates how much we are still learning about the universe’s most extreme events.” This discovery not only expands our understanding of cosmic phenomena but also sparks curiosity about what else might be happening in the vast universe beyond our view.
The findings regarding GRB 250702B were published in The Astrophysical Journal Letters in November 2025. This cosmic event challenges our current understanding and stands as a reminder of the endless mysteries waiting to be uncovered.
