NASA’s SDO Peers Into Huge Coronal Hole

Karen C. Fox and Steele Hill | NASA

NASA’s SDO Peers Into Huge Coronal Hole
NASA released a stunning picture which captured a giant dark hole on the sun's upper half. Credit: NASA

This imagery of the sun captured by NASA’s Solar Dynamics Observatory from May 17-19, 2016, shows a giant dark area on the star’s upper half, known as a coronal hole. Coronal holes are low-density regions of the sun’s atmosphere, known as the corona.

Coronal holes contain little solar material, they have lower temperatures and thus appear much darker than their surroundings. They are visible in certain types of extreme ultraviolet light, which is typically invisible to our eyes, but is colorized here in purple for easy viewing.

Credits: NASA/SDO
Credits: NASA/SDO

These coronal holes are important to understanding the space environment around Earth through which our technology and astronauts travel. Coronal holes are the source of a high-speed wind of solar particles that streams off the sun some three times faster than the slower wind elsewhere.

While it’s unclear what causes coronal holes, they correlate to areas on the sun where magnetic fields soar up and away, without looping back down to the surface, as they do elsewhere.