- Zone of the Sun’s atmosphere visible at eclipses and with temperatures varying from 4500°C to over 1 000 000°C. The high temperatures mean that its spectrum contains lines of highly ionised atoms unknown on the Earth. The chromosphere has a depth of a few thousand kilometres and is filled with rushing energy from the Sun’s surface below. This is expressed in sound waves and by other mechanisms. The chromosphere has an emission spectrum consisting of bright lines on a dark background.