Description: "The twin STEREO spacecraft (called Behind and Ahead denoting their relative positions in space), now almost 120 degrees apart, captured this large and dramatic prominence eruption over about a 30-hour period between Sept. 26-27, 2009. Prominences, called filaments when they are viewed against the surface of the Sun, are clouds of cooler gas suspended above the Suns surface by magnetic forces. This erupting prominence was large enough that both spacecraft were able to observe it for hours on ... |