The gigantic sunspot was observed on the sun by NASA’s Solar Dynamics Observatory on November 3, 2011. This is one of the largest sunspots in years. The spacecraft’s photos of the giant sunspot show the solar region as it comes into view on the northeastern edge, or limb, of the sun. The massive sunspot, called AR1339, is about 50,000 miles (80,000 km) long, and 25,000 miles (40,000 km) wide. For comparison, Earth itself is only 8,000 miles (12,800 km) wide. The sunspot is actually a group of nearby darkened spots on the sun, some of which are individually wider than planet Earth. Sunspots appear when intense magnetic activity ramps up on the sun, blocking the flow of heat through the process of convection, which causes areas of the sun’s surface to cool down.
These isolated areas then appear dimmer than the surrounding area, creating a dark spot. The intense magnetic activity around sunspots can often cause solar flares, which are large releases of energy that can actually brighten up the sun. Flares are also accompanied by flows of charged particles out into space, called coronal mass ejections, which can wreak havoc on satellites and power grids on Earth if they head our way.