High above the solar surface in the hot million+ C solar corona sits a giant filament of cooler (~50,000 C), denser material, both supported and restrained by solar magnetic fields. If this filament should become unstable as they sometimes do
On April 22, 2012, filament material uncurled as an erupting prominence around sunspot group AR11463. There was a C1.8 solar flare and the resulting eruption produced a SCORE-C CME detected by SOHO/LASCO C2 at 15:30 UT.
An eruption of plasma from just behind the solar limb observed by SDO with the 304 Angstrom camera.This shows material at temperatures around 60,000-80,000 Kelvin. This produced a CME that went out the left side (East) of the Sun starting around 2 UT. At ~1000 km/s the CME has a SCORE O (for ordinary). NASA produced a computer model predicting the CME will impact STEREO Behind on 4/17 at 7:40 UT (but not Earth).
On March 12, 2012, Sunsflare posted a video asking if anyone could identify a circular object seen in SDO coronal images. The video was also posted on Facebook with the same question posed. I answered the question on Facebook but