NASA's Solar Dynamics Observatory has a nice video of the solar flare and coronal mass ejection from February 15th which I uploaded to YouTube:
[More formats are available at NASA's SDO site.] Whoa! We're in no major danger from this event, but wow, that's cool. So what did you just see?
As I described in an earlier post, Sunspot 1158 is an active region on the Sun, with a lot of magnetic energy stored up. That energy got released with a bang on Tuesday, creating a solar flare -- essentially a magnetic bomb on the surface of the Sun -- and a coronal mass ejection (CME) -- a huge eruption of subatomic particles blasting outward from the Sun.
The flare can be seen as the sudden bright flash just below and to the right of the center of the Sun's disk. At the same time you can see an expanding circle of light centered on the Sun. That last bit is the CME. We see these launching off the Sun quite often; usually headed off to the side, looking like a big loop or light-bulb shape moving off. When they head straight Earth, though, they look like a circle that expands as it approaches. That's how you can tell we're in the way!
As I mention in the other post (and in Chapter 2 of my book Death from the Skies!), flares and CMEs can present a real danger to Earth, though this particular event wasn't too worrisome. The most likely outcome is some disruption in radio communications, but more happily it also means potentially intense aurorae, northern and southern lights. SpaceWeather.com is always a good place to look for images of these beautiful events. There may be some aurorae tonight from this event, in fact. The NOAA Space Weather Prediction Center posts aurora maps, so you can see if you live in an area that might be treated with these eerie and literally unearthly lights.