This image from NASA’s Solar Dynamics Observatory on March 16, 2015, shows two dark spots, called coronal holes. The lower coronal hole, a polar coronal hole, was one of the biggest observed in decades. (NASA/SDO)
Home This image from NASA’s Solar Dynamics Observatory on March 16, 2015, shows two dark spots, called coronal holes. The lower coronal hole, a polar coronal hole, was one of the biggest observed in decades. (NASA/SDO) This image from NASA’s Solar Dynamics Observatory on March 16, 2015, shows two dark spots, called coronal holes. The lower coronal hole, a polar coronal hole, was one of the biggest observed in decades. (NASA/SDO)
This image from NASA’s Solar Dynamics Observatory on March 16, 2015, shows two dark spots, called coronal holes. The lower coronal hole, a polar coronal hole, was one of the biggest observed in decades. (NASA/SDO)
