gamma ray
Americannoun
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a photon of penetrating electromagnetic radiation gamma radiation emitted from an atomic nucleus.
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a photon emitted by an electron as a result of internal conversion.
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electromagnetic radiation with wavelengths shorter than approximately one tenth of a nanometer.
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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.
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See more at radioactive decay
Etymology
Origin of gamma ray
First recorded in 1900–05
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The estimated frequency of these annihilation events based on the observed gamma ray intensity also fits within expected theoretical ranges.
From Science Daily • Nov. 29, 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
Answers may come with the construction of a huge new gamma ray telescope called the Cherenkov Telescope Array.
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
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
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
