solar prominence An erupting solar prominence observed by the Solar Dynamics Observatory satellite on March 30, 2010.
© NASA/GSFC/SDO/AIA
A massive prominence is jutting out over the sun's southeastern limb today--and it's leaking plasma. Sylvain Chapeland filmed the gigantic structure from his backyard observatory in Gex, France:


"I tracked it for 2 hours using my 100mm refractor with an H-alpha filter (tuned to the red glow of solar hydrogen)," explains Chapeland. " It was wonderful to discover in the resulting video so many fine patches of gas falling downward along the magnetic field lines. I measured some of them speeding at around 100,000 mph!"

Prominences like these are the subject of cutting edge research. Inside the structures, solar magnetic fields lift planet-sized clouds of hydrogen above the surface of the sun. Sometimes, hydrogen-rich plasma leaks out, producing a type of glowing hot rain.

Mysteriously, some of the "raindrops" plummet faster than ambient magnetic forces seem to allow. The theory of magnetic diffusion applied to solar prominences predicts much slower speeds than the 100,000 mph Chapeland measured. This rainstorm is breaking the speed limit!

There's more: A number of large prominences have sprung up around the periphery of the solar disk. Here they are. Amateur astronomers, if you have a safely-filtered solar telescope, now is a good time to look at the sun.