NASA's Solar Dynamics Observatory caught the Sun in a jolly good mood! The "smiley" face is actually dark patches on the Sun as seen in ultraviolet light.&nbsp;The patches are coronal holes or temporary regions of relatively cool, less dense plasma the Sun's corona which allows solar wind to escape into space.Despite the happy solar smile, the sun's coronal holes may actually mean that the Earth would be hit with a solar storm.#sun #smiley #solarstorm #ultraviolet #NASA