From Earth, the sun appears to be one big blazing mass, but a closer look reveals it its exterior is much more varied than it appears.

From Earth, the sun appears to be one big blazing mass, but a closer look reveals it its exterior is much more varied than it appears. An image of the sun captured by NASA’s Solar Dynamics Observatory in mid-May shows what appears to be a large void in its atmosphere. Such areas are technically known as coronal holes and are marked by less sizzling temperatures, lower concentrations of solar materials, and faster winds. While they’re not typically visible, they can be made apparent through a combination of fancy equipment and special coloration techniques. Why they form remains unknown.