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

It then releases a gamma ray to reach a stable state.

From Science Daily • Apr. 14, 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

Because of this, he views the data as a strong candidate for long-sought gamma ray emission from dark matter.

From Science Daily • Nov. 29, 2025

"It could be that these gamma ray bursts and supernova explosions are not necessarily directly linked to each other and they could be separate processes going on," he told BBC News.

From BBC • Apr. 12, 2024

New observations in the next few years, particularly by gravitational wave detectors like LIGO, should enable us to discover the origin of the gamma ray bursts.

From "A Brief History of Time: And Other Essays" by Stephen Hawking