Two Unusual CMEs
Caption: Not to be outdone by fall's explosion of color, the Sun issued a series of spectacular eruptions late last week. The first one (above, right), perplexed even seasoned solar physicists with its unique appearance. Coronal mass ejections (CMEs) tend to take on a shape that resembles a "lightbulb" (see e.g. this previous Hot Shot). The one last week, however, had more the shape of a dark keyhole, or a bulb on top of a column. The most likely explanation appears to be a combination of several coincidences - the chance juxtaposition of unrelated solar structures, enhanced by the image processing that removes the "background image", and a visual illusion that enhances the apparent contrast of the column.
A second CME (above, left) showed an unusually high level of structure, with a definite "twist" to the material being ejected. Although unusual, this is not a "one-of-a-kind" CME, though. Another event was a filament eruption, featured on the SOHO Pick of the Week page.