The star of any solar eclipse is, of course, the sun. And total eclipses give the sun’s wispy, tenuous atmosphere the spotlight. This region, called the corona, is normally too dim to observe directly. But with the moon blocking the sun’s bright disk, the corona comes into view.
And the view is dazzling. The corona’s hot plasma is a radiant, ever-changing tiara, full of bright loops and whorls that bend, sway and snap. Sometimes, one of those loops breaks off, sending high-energy material rippling through space in what’s called a coronal mass ejection, or CME. When aimed at Earth, these bursts can trigger auroras — or damage satellites and knock out power grids.