Solar filaments, aka prominences, arc upwards

Half of huge orange sphere with a gigantic arc coming out from it, and a tiny Earth for scale.
Solar filaments (aka prominences when viewed on the limb of the sun) are large, bright features extending outward from the sun’s surface. This image, from March 2010, shows a solar eruptive prominence (filament), with Earth superimposed for a sense of scale. Image via NASA.

Solar filaments, aka prominences

Filaments are ropes of solar material and magnetic fields, arcing up from the visible surface of the sun. When they erupt, they can produce solar flares and CMEs.

When a solar filament is viewed on the limb of the sun, it’s called a prominence. The largest prominences can extend from the sun’s visible surface to hundreds of times Earth’s diameter.

Prominences (filaments) are anchored to the sun’s surface in its photosphere. They extend outward into the sun’s hot outer atmosphere, called the corona.

A filament or prominence forms over timescales of about a day. Stable prominences may persist in the corona for several months, looping hundreds of thousands of miles into space.

These structures can often be seen as red or pink features during a total solar eclipse.

Close-up of one edge of the eclipsed sun, with a red prominence extending upward.
A prominence seen in the sun’s chromosphere during the July 2, 2019 total solar eclipse. Prominences are made of tangled magnetic field lines that keep dense concentrations of solar plasma suspended above the sun’s surface. They are anchored to the sun’s visible surface and extend outwards through the chromosphere and out into the corona. The red hue of the chromosphere is only apparent during an eclipse. This image – via ESA – was taken by the ESA-CESAR team observing the eclipse from ESO’s La Silla Observatory in Chile, South America.

Bottom line: Solar filaments (aka prominences, when viewed on the limb of the sun) are large, bright arcs of solar material and magnetic fields.

March 26, 2022

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