Between 4 and 6 September, NASA’s Solar Dynamics Observatory spacecraft captured extreme ultraviolet images of a large, well-developed “hole” in the Sun’s corona followed by the formation of another, larger hole nearby. Coronal holes are dark, cooler regions of the Sun’s outer atmosphere associated with open magnetic field lines where electrically charged particles making up the solar wind readily stream out into space. Brighter areas in this view are regions where magnetic activity is strong.
The Sun emitted a mid-level solar flare, peaking at 8:33am BST on 24 August 2015. NASA’s Solar Dynamics Observatory, which watches the Sun constantly, captured the image of the event shown here. Although harmful radiation from such a flare cannot pass through Earth’s atmosphere, intense flares can disturb the atmosphere in the layer where GPS and communications signals travel.