NASA's IRIS Helps Explain Mysterious Heat of the Solar Atmosphere

NASA's newest sun-watcher, the Interface Region Imaging Spectrograph, launched in 2013 with a specific goal: track how energy and heat coursed through a little understood region of the sun called the interface region. Sandwiched between the solar surface and its outer atmosphere, the corona, the interface region is where the cooler temperatures of the sun's surface transition to the hotter temperatures above. Moreover, all the energy to power the sun's output -- including eruptions such as solar flares and the sun's constant outflow of particles called the solar wind -- must make its way through this region.

In the Oct. 17, 2014, issue of Science magazine, five papers based on IRIS data highlight different aspects of the energy's journey from the sun’s surface through its atmosphere. By looking at various regions of the interface region in unprecedented resolution, the papers offer clues to what heats the corona to unexplained temperatures of millions of degrees, far hotter than the surface of the sun itself, as well as what causes great writhing movement and accelerated particles throughout the solar atmosphere.