Figure 9-15 Prominences (a) A huge prominence arches above the solar surface in this SOHO image taken in 2001. The radiation that exposed this picture is from singly ionized helium at a wavelength of 30.4 nm, corresponding to a temperature of about 50,000 K. (b) The gas in these prominences was so energetic that it broke free from the magnetic fields that shape and confine it. This coronal mass ejection occurred in 1999 (and did not strike Earth, which is shown for size).