photosphere

noun pho·to·sphere \ ˈfō-tə-ˌsfir \

Definition of photosphere

1 : a sphere of light or radiance

2 : the luminous surface layer of the sun or a star

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photospheric

play \ˌfō-tə-ˈsfir-ik, -ˈsfer-\ adjective

See photosphere defined for kids

Recent Examples of photosphere from the Web

Even when 99 percent of the sun's surface (the photosphere) is obscured during the partial phases of a solar eclipse, the remaining crescent Sun is still intense enough to cause a retinal burn.

— leada gore, AL.com, "Solar eclipse 2017: Why is it dangerous to watch a total solar eclipse?," 4 Aug. 2017
If skies are clear, observers will be able to see the sun’s halo-like corona, which is usually obscured by the brightness of the photosphere.

— deborah netburn, latimes.com, "Parades, parties and port-a-potties: Eclipse mania is taking hold from coast to coast," 20 July 2017
But just a few hundred miles above the photosphere, in the star's corona, the temperature suddenly jumps to several million degrees.

— william harwood, CBS News, "NASA solar probe to "touch" sun's atmosphere," 31 May 2017
The visible surface of the sun, the photosphere, has a temperature of about 6,000 degrees Fahrenheit.

— william harwood, CBS News, "NASA solar probe to "touch" sun's atmosphere," 31 May 2017
The photosphere has a temperature of between 4,500 and 6,000 degrees Kelvin, while the corona's temperatures are more like 1,000,000 or 2,000,000 K and can blaze as hot as 20,000,000 K in the right conditions.

— jay bennett, Popular Mechanics, "NASA Is Building a Spacecraft That Will Fly Into the Sun's Atmosphere," 30 Mar. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'photosphere.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.