Repost from @whitehouse:
Check out this look at our sun taken by @NASA’s Solar Dynamics Observatory. The SDO watches the sun constantly, and it captured this image of the sun emitting a mid-level solar flare on June 25. Solar flares are powerful bursts of radiation. Harmful radiation from a flare can't pass through Earth's atmosphere to physically affect humans on the ground. But when they're intense enough, they can disturb the atmosphere in the layer where GPS and communications signals travel. #AstronomyNight