gamma rays



  • The shortest-wavelength form of electromagnetic radiation, with a wavelength of 0.1nm or less. Because gamma rays are the most energetic radiation observable, they yield information about the most energetic events. This means that astronomers can get information about objects like gamma ray bursters only by observing in gamma ray frequencies. This can be done in space – gamma rays were first observed from space by accident by satellites intended to spot nuclear weapons tests – or by setting up detectors on the Earth’s surface to spot the bursts of visible Cerenkov radiation produced by gamma rays striking the top of the Earth’s atmosphere.


  • plural noun electromagnetic radiation given off by some radioactive substances


  • Very high frequency electromagnetic radiation that is produced during nuclear transitions or reactions. Such rays consist of high-energy photons, are unaffected by magnetic fields, and readily penetrate living tissue, producing serious harm when protective shielding is not utilized. Gamma rays are emitted, for instance, by various radioactive elements, and are one of the products when cosmic rays strike particles in the atmosphere. Such rays have wavelengths of between approximately 10-11 and 10-13meter, corresponding to frequencies of approximately 1019 and 1021 Hz, respectively. Also called gamma radiation.
  • synonymgamma radiation


  • plural noun electromagnetic rays that are shorter than X-rays, given off by radioactive substances and used in food irradiation

General Science

  • noun radiation from gamma rays