This innermost region of the sun’s atmosphere is primarily of historical significance, since it was in the spectrum of this light during an eclipse in 1868 that the element helium was first identified more than 25 years before it was finally recognized on earth. The chromosphere is an irregular layer above the photosphere where the temperature rises from 6000° C to about 20,000° C. At these higher temperatures hydrogen emits light that gives off a reddish color. This colorful emission can be seen in prominences that project above the limb of the sun during total solar eclipses. This is what gives the chromosphere its name (color-sphere). However chromosphere is essentially featureless and warrants only passing attention.