Bell Tone Bell Tone Music Narrator: At first glance, these images might make you think that you had wandered into an art gallery. The truth is far more interesting. Although they look like impressionist-style paintings, they are actually made from data collected by the Solar Dynamics Observatory, or SDO, and show the heating and cooling of plasma in the sun's ultra-hot atmosphere. Dr. Nicholeen Viall: To produce these temperature change maps, we started with an interesting active region on the sun. We used data take with SDO's Atmospheric Imaging Assembly over a 24 hour period in 6 different wavelengths. Then we looked at these data one pixel at a time. By comparing the brightness of a pixel over time in two different wavelengths, we could tell if the plasma was heating up or cooling down, and then we could color-code it. A computer program ran this comparison over and over again for each pixel, 160,000 in all, and created a color map of how long the plasma to heat or cool. What we found was that most of the coronal plasma is in a state of cooling after having been rapidly heated by bursts of energy called nanoflares. We made these maps for many different wavelength combinations and different time periods. Since each wavelength represents a different temperature, this allows us to see how much the plasma is cooling down. Narrator: This creative and effective way of analyzing the incredibly complex behavior of the sun's atmosphere will help scientists gain greater understanding of why the corona is much hotter than the solar surface just beneath it. Music Beeping Beeping