Record-breaking Long Gamma-ray Burst

Produced by the Space Telescope Science Institute’s Office of Public Outreach in collaboration with NASA’s Universe of Learning partners: Caltech/IPAC, Center for Astrophysics | Harvard & Smithsonian, and NASA Jet Propulsion Laboratory.

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[00:00:00.00] A series of astrophotography images scrolls by in a photo mosaic. Title Text: News from the Universe.

 

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[00:00:11.44] Text: December 16, 2025. Record-Breaking Long Gamma-Ray Burst. An artist's concept drawing shows a gamma-ray burst as a pink link passing through a bright point of light.

 

[00:00:21.90] Text: Gamma-ray bursts, GRBs, are the most powerful known explosions in the universe.

 

[00:00:30.30] Astronomers have released data on the longest GRB ever detected, which occurred on July 2, 2025. The GRB emits white and pink light among a field of white and pink galactic dust.

 

[00:00:42.55] Text: GRB 250702B stood out for lasting more than seven hours, when typical GRBs last seconds. Two graphs show the duration and brightness of a typical gamma-ray burst as compared to GRB 250702B.

 

[00:00:57.63] Text: The burst went on for so long that no high-energy monitor in space was equipped to fully observe it, said astrophysicist Eric Burns. The graphs show a typical burst lasting 60 seconds. The graphs show similar peaks in maximum brightness.

 

[00:01:12.71] Text: Telescopes across the Earth and in space collaborated to study the unique event. Three detection zones from the Fermi GBM and Swift B A T overlay across a photomosaic of the Milky Way.

 

[00:01:23.80] Text: Astronomers used multiple missions to narrow down the location of the GRB to a distant, dusty galaxy in the constellation Scutum. Localization by Einstein Probe. X-ray image by Swift XRT. Optical image by DSS. Photos of increasing detail zero in on GRB 250702B. Text: Optical and infrared image by Blanco and Gemini. Infrared image by Gemini.

 

[00:01:50.40] An infrared image by the Webb telescope shows the exact location.

 

[00:01:57.18] Text: The best explanation for the cause of GRB 250702B is a black hole destroying a star. An animation shows material streaming off a blue-white star.

 

[00:02:07.03] The outstanding question is, how massive was the black hole? The animation continues to show material streaming off the star.

 

[00:02:14.98] Text: This animation shows a smaller, stellar-mass black hole shredding its companion helium star, a rare type of star that has been stripped of its hydrogen. Clouds of white helium flow away from the star, creating a ball of debris with the appearance of cotton.

 

[00:02:33.02] Text: The interaction first produces X-rays and then gamma-rays, followed by the explosion of the helium star. A beam of pink light comes from the cloud. The cloud then explodes in all directions.

 

[00:02:44.84] Text: It is also possible that a more massive, intermediate-size black hole destroyed a star that passed too close to its gravitational field. A photo from the James Webb Space Telescope shows GRB 250702B within its galaxy.

 

[00:02:59.02] Text: While the extreme amounts of cosmic dust in the galaxy blocked some of the GRB evolution from view, the event has provided valuable data for understanding the longest GRBs. The image from the Webb telescope shows the galaxy containing 250702B among a field of hundreds of other stars and galaxies.

 

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[00:03:17.10] This news was brought to you in part by NASA's Goddard Space Flight Center in Greenbelt, Maryland.