This video of an M-class solar flare condenses three hours of explosion into a dramatic 1-minute video. The mesmerising part is the graceful way the fountain of flowing plasma floats back to the sun's surface. It doesn't just plop back down, rather, it follows the star's magnetic field lines.
The flare was recorded on September 25, just one day after a larger X-class flare eruption, by the Solar Dynamics Observatory. The earlier flare may have been larger, but the observatory, which is orbiting the earth, is showing us a more dramatic image of the smaller one.
M is the second-highest in the flare classification (it goes B, C, M, X). Similar to the Richter scale, each letter represents a tenfold increase in energy output -- X is 10 times an M and 100 times a C. Class X flares can cause radiation storms and worldwide black outs. That's why NASA closely monitors and classifies them.
This particular flare might be just a hiccup for the sun, but Phil Plait at Bad Astronomy points out:
"…the total energy released would still dwarf the combined nuclear might of every country on Earth! By a lot."