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Answer: Gamma-ray bursts (GRBs) are short-lived bursts of gamma-ray light, the most energetic form of light. Lasting anywhere from a few milliseconds to several minutes, they shine hundreds of times brighter than a typical supernova. Evidence from satellites like Swift and Fermi indicates that the energy behind a burst comes from the collapse of matter into a black hole.

Discovery

GRBs were discovered serendipitously in the late 1960s by U.S. military satellites on the lookout for Soviet nuclear testing. The satellites carried gamma ray detectors since a nuclear explosion produces gamma rays. They didn't find any violations of the nuclear treaty, but they did discover bright bursts of gamma rays from beyond the solar system.

Two classes

When astronomers looked at the number of bursts versus how long they lasted, they found two classes: long-duration and short-duration. These two classes are likely created by different processes, but the end result in both cases is a brand new black hole.

The Swift observatory

Swift is a multi-wavelength observatory dedicated to the study of gamma-ray burst science. Its three instruments observe GRBs and afterglows in the gamma-ray, X-ray, ultraviolet, and optical wavebands.

• Swift discovers approximately 100 bursts per year.
• The Burst Alert Telescope detects GRBs and accurately determines their positions on the sky.
• Swift relays a 3 arcminute position estimate to the ground within 20 seconds of the initial detection.
• In less than approximately 90 seconds the spacecraft autonomously repoints itself to observe the afterglow with its X-ray and UV/optical telescopes.

Claims

• id: C1 claim: Gamma-ray bursts are short-lived bursts of gamma-ray light. source: S1 evidence: "Gamma-ray bursts (GRBs) are short-lived bursts of gamma-ray light"
• id: C2 claim: GRBs fall into long-duration and short-duration classes. source: S1 evidence: "long-duration and short-duration."
• id: C3 claim: Swift discovers approximately 100 bursts per year. source: S2 evidence: "Swift discovers approximately 100 bursts per year."

Sources

• [S1] Imagine the Universe!. NASA. https://imagine.gsfc.nasa.gov/science/objects/bursts1.html . License: US government work, public domain. Accessed 2026-11-04.
• [S2] Swift: About Swift. NASA. https://swift.gsfc.nasa.gov/about_swift/ . License: US government work, public domain. Accessed 2026-11-04.

License: this note is CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Summary by iinventedlight (AI-assisted).

@misc{iil_note_eg7fecnk,
  author = {{iinventedlight}},
  title = {{Gamma-ray bursts and the Swift observatory}},
  howpublished = {iinventedlight Library},
  year = {2026},
  date = {2026-11-04},
  url = {https://iinventedlight.com/library/notes/gamma-ray-bursts/},
  note = {Permanent ID iil:note:eg7fecnk. License: CC-BY-4.0.},
}

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