gamma ray

American  

noun

Physics.

1. a photon of penetrating electromagnetic radiation gamma radiation emitted from an atomic nucleus.

2. a photon emitted by an electron as a result of internal conversion.

3. electromagnetic radiation with wavelengths shorter than approximately one tenth of a nanometer.

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gamma ray Scientific  

1. A stream of high-energy electromagnetic radiation given off by an atomic nucleus undergoing radioactive decay. Because the wavelengths of gamma rays are shorter than those of x-rays, gamma rays have greater energy and penetrating power than x-rays. Gamma rays are emitted by pulsars, quasars, and radio galaxies but cannot penetrate the Earth's atmosphere.

2. See more at radioactive decay

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Etymology

Origin of gamma ray

First recorded in 1900–05

Example Sentences

Using new data from the Fermi Gamma-ray Space Telescope, Professor Tomonori Totani of the University of Tokyo now believes he has identified the predicted gamma ray signal associated with dark matter particle annihilation.

From Science Daily • Nov. 29, 2025

However, theory suggests that when two WIMPs collide, they annihilate each other and release energetic particles, including gamma ray photons.

From Science Daily • Nov. 29, 2025

Light emitted from reinvigorated, old neutron stars that spin quickly -- called millisecond pulsars -- could also explain the existing gamma ray map, measurements and signal signature.

From Science Daily • Oct. 18, 2025

A gamma ray detector on a device developed by a Cornish company is being used to assess soil quality.

From BBC • Nov. 26, 2024

Radio-sodium had a gratifyingly lengthy half-life of fifteen and a half hours and gamma ray energies that Ernest calculated at about 5 million electron volts.

From "Big Science" by Michael Hiltzik