Solar Prominence and Filament, March 9, 2010. This photograph was taken with a hydrogen alpha scope that only shows one wavelength of light, at 656.3 nanometres. This is the particular wavelength of hydrogen alpha light. Observing the Sun in hydrogen alpha makes it possible to see structural details.
Large prominences of plasma lift off the surface of the Sun at tremendous speeds, and they are most easily seen along the edge with the darkness of space behind them. Two large prominences can be seen in the upper right of the photograph, along with several other smaller ones. Also notable in this photo is the smudge shape on the surface in the lower left. This is a solar filament a massive, plasma filled structure tens of thousands of kilometres in length. It would take a dozen or more Earths to cover this much of the Sun's surface. A filament is like a prominence, but seen from above instead of from the side.
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