Photosphere is the name given to that part of the sun which is seen by the naked eye. It seems to be a surface, but is actually a huge layer of gas about five hundred miles deep. It appears brilliant white, becoming brighter toward the center.
The brighter parts of the sun are distinctly granular in shape because of millions of granules constantly moving at such a rapid rate that their form is changed every half minute or so. Along the edges are seen larger irregular areas called faculae, heated gases rising into the atmosphere.
The gases of the photosphere are glowing constantly and reach a temperature close to 6,000 °C. Because they are burning so brightly, they seem to be the actual surface of the sun. It is in the photosphere that deep areas called sunspots develop.
