The Webb telescope sees a mysterious explosion that defies known physics

NASA has announced that researchers using the James Webb Space Telescope have observed GRB 250702B, a long gamma-ray burst and one of the most powerful types of events in the universe. These explosions usually occur when a massive star collapses into a black hole, and emits a short and intense burst of high-energy gamma rays. This event behaved very differently.

“This object exhibits extreme properties that are difficult to explain,” said Huei Sears, a postdoctoral researcher in the Department of Physics and Astronomy at Rutgers School of Arts and Sciences who is studying the explosion. “Usually, these bursts are over in less than a minute, but GRB 250702B lasted for hours and even showed signs of X-ray activity a day earlier.”

Global Attitudes Reveal Abnormal Behavior

Sears explained that observatories around the world are analyzing the details of the incident. This includes teams working with China’s Einstein Probe and the National Science Foundation’s Very Large Array, best known from its appearance in the science fiction film Contact.

The gamma-ray emission continued for at least seven hours, almost double the time of the previous record holder. NASA also released an animation showing one scenario for the event. In this model, a black hole with three times the mass of the Sun, just 11 miles (18 kilometers) in diameter, orbits and collides with its companion star.

Eliza Neights, an astronomer at NASA’s Goddard Space Flight Center in Maryland, said: “This is definitely an explosion unlike any other we’ve seen in the last 50 years.

Possible explanations include Black Holes

Scientists consider several explanations. Another possibility is that this was an unusual gamma-ray burst. One is that it was a super-interference event, where a black hole thousands of times more massive than the Sun rips apart a star that came very close. A very unusual theory suggests a small black hole that merged with a star stripped of helium and burned it from the inside.

Whatever the cause, the black hole did more than bite. It released powerful rockets into space.

Multi-Telescope Effort Wins Event

NASA’s Fermi Gamma-ray Space Telescope first detected the burst on July 2, prompting other instruments to quickly follow. The event was so intense that no single telescope could capture the full picture. Scientists combined data from space and ground-based observatories, collecting gamma rays, X-rays, infrared lights and radio waves. The explosion was not visible in normal light.

Eric Burns, an astronomer at Louisiana State University, said: “Only with the combined power of the instruments of many spacecraft can we understand this phenomenon.”

A Galaxy Far Away Adds Mystery

Images from the Hubble Space Telescope revealed an unusual galaxy in the area of ​​the explosion. At first, it seemed that two galaxies may have merged, or one galaxy was separated by dark dust. Later, Webb’s research showed that the galaxy is about 8 billion light-years away, which means that the explosion happened long before the Earth was formed.

To better understand the galaxy, Sears led the latest observations using Webb’s NIRCam, its primary near-infrared imaging instrument, several months after the event.

Sears said: “In unprecedented and clear detail, we see only one very large galaxy with dust. The galaxy has such a complex structure that it is not 100% clear if there is anything left from the explosion, but if so, it is very faint.

The Mystery Still Unsolved

This finding supports the idea that GRB 250702B was a gamma-ray burst and not a strong interference event. However, researchers have not yet reached a firm conclusion.

“We’ve only seen a few incidents of this type of disruption, so we don’t know for sure how they’re supposed to change,” Sears said. “The many studies on this explosion offer different, and sometimes contradictory, explanations. It’s still very early in our understanding of what really happened.”

Whatever the final explanation, scientists agree that the phenomenon is rare and important.

“This gives us a unique opportunity to study the extremes of how stars and black holes evolve,” Sears said. “GRB 250702B could be an unexpected and new discovery.”

The Webb telescope is also supported by the European Space Agency (ESA), and the Canadian Space Agency (CSA).