- a sphere of light or radiance.
- Astronomy. the luminous visible surface of the sun, being a shallow layer of strongly ionized gases.
Origin of photosphere
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for photosphere
It is from the photosphere, as has been said, that we have won most of our knowledge of the sun.The Outline of Science, Vol. 1 (of 4)
J. Arthur Thomson
The dazzling surface of this globe is called a photosphere (light sphere).
The part of the Sun that we see is its luminous surface, or photosphere.
Only the photosphere may be to a greater or less extent solid or liquid.
Dark spots of a deep bluish black will often be seen on the photosphere of the sun.Astronomy
- the visible surface of the sun, several hundred kilometres thick
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for photosphere
Online Etymology Dictionary, © 2010 Douglas Harper
- The lowest visible layer of a star, lying beneath the chromosphere and the corona. Stars are made entirely of gas and thus have no surface per se, but the gas beneath the photosphere is opaque, so the photosphere acts as their effective visible surface; it is also the boundary from which the Sun's diameter is measured. The Sun's photosphere is a very thin layer made up of numerous granules (transient convective cells) where hot gases rise and give off light and heat. The photosphere of the Sun has a temperature of around 6,000°K and is the region in which sunspot activity is located.
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