Figure 9-6 The Solar Corona (a) This visible-light photograph was taken during the total solar eclipse of July 11, 1991. Numerous streamers are visible, extending millions of kilometers above the solar surface. (b) This X-ray image of the Sun’s corona, taken by the Yohkoh satellite in 1999, provides hints of the complex activity taking place on and in the Sun. The million-degree gases in the corona emit the X rays visible here. (c) This graph shows how temperature varies with altitude in the Sun’s chromosphere and corona and in the transition region between them (white). Note that both the height and temperature scales are nonlinear.