solar wind
Americannoun
noun
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A continuous stream of plasma ejected by the Sun, flowing outward from the corona. This plasma, which consists mostly of protons and electrons, has enough energy to escape the Sun's gravitational field at speeds ranging from about 300 to 800 km (186 to 496 mi) per second and averaging 1,610,000 km (1,000,000 mi) per hour, which allows the solar wind to reach Earth in about 3.9 days. The speed and intensity of the solar wind depends on magnetic activity at different regions of the Sun. The solar wind spreads out from the Sun in a pinwheel pattern as a result of the Sun's rotation, pushing back the interstellar medium to the boundary known as the heliopause. The tails of comets, which always extend away from the Sun regardless of the direction of the comet's motion, are a result of the impact of solar wind, which dislodges ice and other particles from the comet's surface. Similar winds flowing from other stars are called stellar winds.
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See also aurora
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Particularly strong bursts of particles can penetrate the upper atmosphere and disrupt radio communications on Earth.
Etymology
Origin of solar wind
First recorded in 1955–60
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 Moon has been exposed to the solar wind for billions of years.
From Science Daily ● Jul. 21, 2026
That value is considerably lower than measurements from all previously studied near-side samples, but it closely matches the theoretical composition expected after strong solar wind fractionation.
From Science Daily ● Jul. 21, 2026
The samples provided the first direct opportunity to compare how solar wind particles were implanted into soil from both sides of the Moon.
From Science Daily ● Jul. 21, 2026
These far side samples provide the first direct physical evidence that Earth's magnetosphere controls the speed of solar wind particles reaching different parts of the Moon.
From Science Daily ● Jul. 21, 2026
Matter blown outward from the Sun’s atmosphere, the solar wind, carries fragments of dust and ice back behind the comet, making an incipient tail.
From "Cosmos" by Carl Sagan
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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.