SDO: Year 4

- The sun is always changing and NASA's Solar Dynamics Observatory is always watching. Launched on Feb. 11, 2010, SDO keeps a 24-hour eye on the entire disk of the sun, with a prime view of the graceful dance of solar material coursing through the sun's atmosphere, the corona. SDO's fourth year in orbit was no exception: NASA released this movie of some of SDO's best sightings of the year, including massive solar explosions and giant sunspot shows. SDO captures images of the sun