sunspot

American  

[suhn-spot] / ˈsʌnˌspɒt /

noun

1. one of the relatively dark patches that appear periodically on the surface of the sun and affect terrestrial magnetism and certain other terrestrial phenomena.

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sunspot British  

/ ˈsʌnˌspɒt /

noun

1. any of the dark cool patches, with a diameter of up to several thousand kilometres, that appear on the surface of the sun and last about a week. They occur in approximately 11-year cycles and possess a strong magnetic field

2. informal a sunny holiday resort

3. a small cancerous spot produced by overexposure to the sun

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sunspot Scientific  

/ sŭn′spŏt′ /

1. Any of the dark, irregular spots that usually appear in groups on the surface of the Sun (its photosphere), lasting from a few days to several weeks or more. Sunspots appear dark because they are cooler, by up to 1,500°K, than the surrounding photosphere. They are associated with strong magnetic fields and solar magnetic storms moving in a vortex pattern, similar to a tornado on Earth. The number of sunspots waxes and wanes over an 11-year period; at maximum activity there are often increased numbers of solar flares.

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Other Word Forms

• sunspotted adjective
• sunspottedness noun

Etymology

Origin of sunspot

First recorded in 1805–15; sun + spot

Example Sentences

“Broadly speaking, though, we do know that activity and sunspot numbers should increase in this part of the cycle,” Tom Morgan, a meteorologist for the Met Office, said.

From New York Times • May 18, 2024

On Wednesday morning, astronomers noted a series of solar flares and coronal mass ejections — essentially, giant explosions of energy — emanating from a massive sunspot more than 15 times the diameter of Earth.

From Los Angeles Times • May 10, 2024

Scientists are now monitoring this sunspot region and analyzing for a possible outburst of plasma from the sun, also known as a coronal mass ejection, that might be directed at Earth.

From Washington Times • Dec. 15, 2023

Scientists are now monitoring this sunspot region and analyzing for a possible outburst of plasma from the sun, also known as a coronal mass ejection, directed at Earth.

From Seattle Times • Dec. 15, 2023

Sitting cross-legged on the carpet, in a sunspot bright as the open sea, Uhmma unfurled her fingers.

From "A Step from Heaven" by An Na