The European Space Agency/NASA Solar and Heliospheric Observatory, or SOHO, captured this image of a gigantic coronal hole hovering over the sun’s north pole on July 18, 2013, at 9:06 a.m. EDT. Coronal holes are dark, low-density regions of the sun’s outermost atmosphere, the corona. They contain little solar material, have lower temperatures, and therefore, appear much darker than their surroundings.
To read more about this discovery and view an image of this coronal hole, visit: https://www.nasa.gov/content/goddard/large-coronal-hole-near-sun-north-pole/index.html#.Ue6fxoXTovQ
This article is a great extension to the NASA Explorer Schools featured lesson, Geometry: Space Math Problems—Solar Storms. This lesson can be found on the NES Virtual Campus.