pho·​to·​sphere | \ ˈfō-tə-ˌsfir How to pronounce photosphere (audio) \

Definition of photosphere

1 : a sphere of light or radiance
2 : the luminous surface layer of the sun or a star

Keep scrolling for more

Other Words from photosphere

photospheric \ ˌfō-​tə-​ˈsfir-​ik How to pronounce photospheric (audio) , -​ˈsfer-​ \ adjective

Examples of photosphere in a Sentence

Recent Examples on the Web This set of magnetometers will measure magnetic variation throughout the spacecraft's orbit, which rangers from out beyond Venus to a close distance of 9 solar radii, or only 3.85 million miles from the photosphere. Jay Bennett, Popular Mechanics, "The New Science of the Sun Will Be Astounding—And Possibly Terrifying," 9 Aug. 2018 This instrument will measure magnetic and electric fields in the sun's atmosphere to help scientists better understand why the corona is so much hotter than the photosphere. Elizabeth Howell,, "Here Comes the Sun! Parker Solar Probe Instruments See 'First Light'," 25 Sep. 2018 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,, "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,, "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.

See More

First Known Use of photosphere

1664, in the meaning defined at sense 1

History and Etymology for photosphere

photo- + -sphere; in sense 2 probably as translation of German Lichtatmosphäre

Keep scrolling for more

Learn More about photosphere

Time Traveler for photosphere

Time Traveler

The first known use of photosphere was in 1664

See more words from the same year

Statistics for photosphere

Cite this Entry

“Photosphere.” Dictionary, Merriam-Webster, Accessed 29 May. 2020.

More from Merriam-Webster on photosphere

Rhyming Dictionary: Words that rhyme with photosphere Encyclopedia article about photosphere

Comments on photosphere

What made you want to look up photosphere? Please tell us where you read or heard it (including the quote, if possible).


See Definitions and Examples »

Get Word of the Day daily email!

Test Your Vocabulary

May 2020 Words of the Day Quiz

  • a blooming wisteria tree
  • Which is a synonym of exiguous?
Spell It

Can you spell these 10 commonly misspelled words?


Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!