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

See Examples For:

gamma ray

The team also tested whether the proposed blazar population would produce too many gamma rays compared with the known extragalactic gamma ray background measured by Fermi.

From Science Daily ● May 24, 2026

Measurements show that this distant supernova closely matches the brightness and spectral features of SN 1998bw, a well known supernova linked to a gamma ray burst that exploded much closer to Earth.

From Science Daily ● Dec. 28, 2025

Further support could come from finding the same gamma ray signature in other regions rich in dark matter.

From Science Daily ● Nov. 29, 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

But despite the close agreement in position Helfand and Long do not insist that the gamma ray outburst is associated with the supernova remnant.

From "Cosmos" by Carl Sagan