NASA/IRIS
This image from the Interface Region Imaging Spectrograph (IRIS) shows emission from hot plasma (T ~ 80,000-100,000 K) in the Sun's transition region - the atmospheric layer between the surface and the outer corona. The bright, C-shaped feature at upper center shows brightening in the footprints of hot coronal loops, which is created by high-energy electrons accelerated by nanoflares. The vertical dark line corresponds to the slit of the spectrograph. The image is color-coded to show light at a wavelength of 1,400 Angstroms. The size of each pixel corresponds to about 120 km (75 miles) on the Sun. (Image courtesy NASA/IRIS)
