Scientists have detected an extremely highly effective burst of gamma radiation that repeated a number of occasions over a single day … they usually can’t fairly clarify it. EarthSky’s Will Triggs has the story in this quick video.
- Astronomers have noticed a mysterious gamma-ray burst. It’s not like any we’ve detected earlier than.
- Most gamma-ray bursts final simply minutes on the most. They happen when a large star dies or is ripped aside.
- However this gamma-ray burst lasted for a day. That’s unprecedented. So what was the supply of this mysterious gamma-ray burst?
ESO printed this unique story on September 9, 2025. Edits by EarthSky.
Mysterious gamma-ray burst is not like any detected earlier than
Astronomers have detected an explosion of gamma rays that repeated a number of occasions over the course of a day, an occasion not like something we’ve witnessed earlier than. The supply of the highly effective radiation was outdoors our galaxy, its location pinpointed by the European Southern Observatory’s Very Massive Telescope (VLT). Gamma-ray bursts are probably the most highly effective explosions within the universe, usually brought on by the catastrophic destruction of stars. However no recognized state of affairs can fully clarify this new gamma-ray burst, whose true nature stays a thriller.
Antonio Martin-Carrillo, an astronomer at College Faculty Dublin in Eire is the co-lead creator of a research on this sign, printed in The Astrophysical Journal Letters on August 29, 2025. Martin-Carrillo stated this gamma-ray burst is:
not like another seen in 50 years of gamma-ray burst observations.
A one-of-a-kind gamma-ray burst
Gamma-ray bursts are probably the most energetic explosions within the universe. Catastrophic occasions – like large stars dying in highly effective blasts or black holes ripping aside stars – can produce gamma-ray bursts. They normally final milliseconds to minutes. However this sign – GRB 250702B – lasted a couple of day. Andrew Levan, astronomer at Radboud College, The Netherlands, and co-lead creator of the research, stated:
That is 100 to 1,000 occasions longer than most gamma-ray bursts.
Martin-Carrillo added:
Extra importantly, gamma-ray bursts by no means repeat because the occasion that produces them is catastrophic.
The preliminary alert about this gamma-ray burst got here on July 2, 2025, from NASA’s Fermi Gamma-ray House Telescope. Fermi detected not one however three bursts from this supply over the course of a number of hours. Retrospectively, astronomers additionally found the supply had been lively virtually a day earlier. The Einstein Probe – an X-ray house telescope mission by the Chinese language Academy of Sciences with the European House Company (ESA) and the Max Planck Institute for Extraterrestrial Physics – made these earlier observations. It’s the primary time such a protracted and repeating gamma-ray burst has been seen.
These observations solely offered an approximate location for the gamma-ray burst. And that location was towards the airplane of our galaxy, crowded with stars. Due to this fact, the crew turned to ESO’s VLT to pinpoint the precise supply inside this space. Levan stated:
Earlier than these observations, the final feeling locally was that this gamma-ray burst will need to have originated from inside our galaxy. The VLT basically modified that paradigm.
Pinpointing the mysterious gamma-ray burst
Utilizing the VLT’s HAWK-I digicam, they discovered proof that the supply may very well reside in one other galaxy. This was later confirmed by the NASA/ESA Hubble House Telescope. Martin-Carrillo stated:
What we discovered was significantly extra thrilling: the truth that this object is extragalactic signifies that it’s significantly extra highly effective.
The scale and brightness of the host galaxy counsel it could lie a number of billion light-years away. However scientists will want extra knowledge to refine this distance.
This video zooms in on the mysterious gamma-ray burst GRB 250702B. It came about in one other galaxy, however its trigger stays unknown. Video by way of ESO/ L. Calçada/ N. Risinger (skysurvey.org)/ Digitized Sky Survey 2/ VISTA Hemisphere Survey/ A. Levan, A. Martin-Carrillo et al. Music: Azul Cobalto.
Why did it happen?
The character of the occasion that brought on this gamma-ray burst remains to be unknown. One doable state of affairs is a large star collapsing onto itself, releasing huge quantities of vitality within the course of. Levan stated:
If this can be a large star, it’s a collapse not like something we have now ever witnessed earlier than.
That’s as a result of the gamma-ray burst from a large star collapse would have lasted only a few seconds. Alternatively, a star being ripped aside by a black gap might produce a day-long gamma-ray burst. However to clarify different properties of the explosion would require an uncommon star being destroyed by an much more uncommon black gap.
To be taught extra about this gamma-ray burst, the crew has been monitoring the aftermath of the explosion with completely different telescopes and devices, together with the VLT’s X-shooter spectrograph and the James Webb House Telescope. Discovering that this explosion came about in one other galaxy might be key to deciphering what brought on it. Martin-Carrillo stated:
We’re nonetheless unsure what produced this, however with this analysis we have now made an enormous step ahead towards understanding this extraordinarily uncommon and thrilling object.
Backside line: Astronomers have noticed a mysterious gamma-ray burst that lasted for a day. Up to now, all different gamma-ray bursts astronomers have seen have lasted a couple of minutes at most. What brought on this distinctive occasion?
Supply: The Day-long, Repeating GRB 250702B: A Distinctive Extragalactic Transient
