Solar Filament Coalesces in Sun’s Atmosphere

In August 2012, a long filament of solar material coalesced in the Sun's atmosphere. For several days it was visible, appearing from Earth's viewpoint to curl up and over the left side of the Sun. Scientists estimate its length was approximately 186,000 miles, equivalent to 30 Earths placed side by side.

On Aug. 31, 2012, at 4:36 p.m. EDT, the filament expanded and erupted, releasing particles into space at speeds of 900 miles per second. The ejected material did not head directly toward Earth, though some of it did glance off the planet's magnetic environment, or magnetosphere, causing aurora to appear on the night of Monday, Sept. 3. The video shows the eruption—a particularly gorgeous one, even for veteran observers of the Sun—as seen by three NASA spacecraft.