Starship Asterisk*

HEAPOW: X-Class (2011 Aug 15)

The sun's been quiet for a long time, but slowly becoming more active. It's a good thing we have satellites like the Solar Dynamics Observatory to keep an eye on it. The image above shows a solar active region emitting a flare of extreme ultraviolet radiation, as captured by the EUV cameras on SDO. This powerful flare (a so-called "X-class" flare) generated a blast of high-energy radiation towards earth. Fortunately earthlings are protected from the harmful effects of this radiation by the warm blanket of earth's atmosphere. However, more exposed space-farers on the International Space Station, and robotic orbiting communication satellites, are more exposed. This flare also produced a Coronal Mass Ejection, an outburst of charged particles from the solar atmosphere. These ejections produce extremely strong aurorae, but this particular CME was not directed towards earth.