Solar Prominences, March 16, 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. This huge prominence, held aloft by an immense magnetic arch, is one of the largest I've observed in recent years. It would take about a dozen Earths to fill the space below the arch.
This photograph was published in The Journal of the Royal Astronomical Society of Canada (June 2010.)
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