Music: Stella Maris courtesy of Moby Gratis. Information about the individual clips used in this video is available at: http://svs.gsfc.nasa.gov/vis/a010000/a011400/a011460/SDO_Year_4_Visuals_List.html 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 grac
![NASA | SDO: Year 4](https://cdn-ak-scissors.b.st-hatena.com/image/square/6eb16f3b8863a5c38eeb3ed7adcbe4af8e869aac/height=288;version=1;width=512/https%3A%2F%2Fi.ytimg.com%2Fvi%2FNAg4qXsk99c%2Fhqdefault.jpg)