SDO is a great example of how astronomers use light to measure and understand our universe. AIA and EVE look at light from the Sun at very short, extreme ultraviolet, wavelengths. By comparing AIA images we can detect small motions of the corona. HMI looks at visible light. One nice property of light is that we can measure how it interacts with the Sun to measure things at the Sun that are otherwise difficult (if not impossible) to measure. We use the Doppler shift to see the wave motions and the Zeeman effect to see the magnetic field at the surface.
Light is a wonderful thing!