The Grand Daddy Prominence
Some filaments and prominences can reach impressive sizes, and remain visible very far above the solar disk.
This prominence was photographed in June 1946 again through a filter centered on Hα, and extends some 200000 km above the solar surface; the Earth would easily fit under it. The red arch at the bottom of the picture delineates the solar limb. Prominences extending so far up above the photosphere are usually not static, but are expanding outward in an eruptive phase, a phenomenon to which we shall return below.
Written By P. Charbonneau and O.R. White–April 18, 1995