Phenomena · Space Codex
GRB 221009A, the 'BOAT'
On 9 October 2022 a collapsing star about 2 billion light-years away unleashed a burst so bright it saturated most gamma-ray detectors in orbit: likely the brightest seen in 10,000 years.
The brightest gamma-ray burst ever recorded
At a glance
Key points
- Brightest gamma-ray burst ever recorded
- About 70× the previous record
- Detected even by Voyager 1
What gamma-ray bursts are
Gamma-ray bursts were found by accident in 1967 by US Vela satellites built to watch for nuclear tests, and reported in 1973. Bursts lasting longer than about two seconds mostly come from the collapse of massive, rapidly spinning stars; shorter ones mostly come from merging neutron stars, as GW170817 confirmed in 2017. Both kinds launch jets moving at very nearly the speed of light, and we see a burst only when a jet points towards us.
A narrow jet
Long gamma-ray bursts come from jets punched out of collapsing massive stars. This one had a narrow core with sloping wings, never seen before, and was aimed almost straight at Earth. Even Voyager 1 detected it.
Blinding the detectors
The burst was so intense that it saturated most gamma-ray instruments in orbit, and its true peak had to be reconstructed from Fermi data. For about 800 seconds its gamma rays poured into Earth's atmosphere, triggering lightning detectors in India and disturbing the ionosphere for hours. By the total gamma-ray energy received at Earth, it beat the previous record holders, GRB 840304 and GRB 130427A, more than tenfold.
No gold found
Some theorists expected jets from collapsing stars to forge heavy elements such as gold and platinum. Webb observed the fading glow about six months after the burst and found a supernova similar to those behind ordinary long bursts, with no clear sign of those elements. Why this event was so energetic is not settled; a very narrow jet aimed at Earth explains part of its record brightness.
What we still don't know
Whether such extreme bursts need unusual progenitor stars or host galaxies, and how often a burst this bright reaches Earth: the once-in-10,000-years estimate rests on a single event.
Missions
- 1977–
Jupiter 1979, Saturn 1980; interstellar space since 25 Aug 2012.
Related entries
- SupernovaeHow stars explode
- MagnetarsThe strongest magnets in the universe
Sources
- NASA Science: Fermi: brightest gamma-ray burst (opens in a new tab)
- NASA JPL: Brightest cosmic explosion ever detected (opens in a new tab)
- Burns et al. 2023 (arXiv) (opens in a new tab)
- IHEP: LHAASO GRB 221009A (opens in a new tab)
- ESA: Integral: gamma-ray burst strikes Earth (opens in a new tab)
- Blanchard et al. 2024, Nature Astronomy (arXiv) (opens in a new tab)
- Klebesadel, Strong & Olson 1973, ApJ 182:L85 (opens in a new tab)
Last reviewed against these sources. Built from public NASA, ESA and JPL data; not affiliated with or endorsed by any agency.