This composite image—released September 3—showing the sun's bright, active regions over the course of one year allows researchers to follow the migration of these spots from the poles to lower latitudes.
Tracking such bright points of light enables scientists to better time solar cycles, which are roughly 11-year periods in which the sun shifts from active to inactive states. Knowing when the sun will move into an active state is important because during these times massive blasts of supercharged particles—known as coronal mass ejections—can wreak havoc with electronic systems on Earth.
— Dan Vergano and Jane J. Lee
Week's Best Space Pictures: Sun Blazes, Saturn Shadows a Moon, and Mercury Sports a Blast Crater
Mercury shows off a weird crater, a spacecraft visits an oncoming comet, and Iceland erupts.